LED vs. HPS Light Intensity -- What You Should Know

I have been asked in an E-mail to use a light meter from HTGSupply.com to compare a 90W UFO LED to a 600 W HPS

What you should know is that using a light meter is not the best way to compare these two lights.  The benefit of  LED's is that they emits a very specific wavelenght of each light, this is why there are individual colors of LED lights, because each LED emits such a narrow range of light it looks like a single color to our eyes.  An HPS (or MH) on the other hand, emits a greater light intensity.  The light meter will show a higher output of light from the HPS but the problem is that not all the light is available for plants to use during photosynthesis.  Translation, a lot of the light is wasted and a lot of the energy to create that wasted light results in heat generation too.  This is why LED's CAN BE more efficient, they use less energy and only emit light that plants need to do photosynthesis.  The reason I say CAN BE in caps is because it is possible to make an LED that is less expensive, but it emits light that is NOT in the optimal wavelenght for photosynthesis.  This means the light will not promote good plant growth.  The reason this is a problem is that the pigments that absorbs light in plants for photosynthesis are different than the three pigments we have in our eyes that absorb light and let us see color.  Translation, what we see as red is not necessarily the best 'red' that plants need to conduct photosynthesize.  I know that the Tri-Band technology from HTGSupply.com is tested and I personally have grown numerous plant species from seed to flowering under it.

Good Growing
Dr. E.R. Myers


Using a screen or SCROG – re-revisited

An acquaintance of mine did a sort of scientific experiment. He used the same light but different plants and a different area to compare the SCROG method with a traditional grow method where plants are not tied down.
First, he grew using the SCROG method, where he grew multiple plants in 1-2 gallon pots under a 400W HPS. We wanted to test how well the plants would grow in a small space.  He kept the plants at three feet (The wire was 2 feet 8 inches off the floor) with the HPS two feet above the tops. This was a little close as some plants showed signs of heat stress.  (I'd recomed an LED next time) He grew the same variety of plants but grew less plants in larger containers (all in 2 gallon pots). The reasoning for the difference was that he figured with the SCROG method, it would be better to have more plants; with more plant tops to tie onto the fence (He also prefers fencing with 2x3 inch holes vs. chicken wire). He said his yield was greater with fewer big plants that were allowed to grow without being tied down. As I said, this is not a real scientific experiment, because he used different containers. You want only one factor or variable to be different when comparing groups. So, in this case we cannot say for sure if the increased yield was due to larger plants/pots or to not being restrained and tied to a screen. I thought some of you might like to atleast have this information.
As always if anyone has any information or further questions please contact me via E-mail

Good Growing,
Dr. E. R. Myers


E-mail - Ventilation and CO2 Use

Hello. I have answered the first questions about CO2 and plant growth, I had to ask Perry a manager at HTGSupply for the question about the ducting etc. He is much more knowledgable than me about equipment use. His answer is below mine in purple.

Dr. Myers,
Upon reading your article, "Information on CO2 Ventilation for the Growing Season," several answers of mine were answered; however, some of questions remained unanswered.
First- You were clear on the amount of CO2 to release, but I would also like to know:
1. How often should I release it if I have no meter (5 min/hr)?
If you see Perry's comment below, you would be wise to invest in a meter. You will end up using more CO2 if you do not, which means the meter will pay for itself in CO2 savings. This really is the only solution. If you don't know how much CO2 is in the grow area, and how much is being released (time/hr is not going to give you these numbers) no one will be able to tell you if you have enough CO2. You could start out at 5min / hr until you get a meter.
2. At what point during the grow cycles are critical?
a)Is it optimal to provide CO2 from seedling to harvest?

Great question!  CO2 is needed for photosynthesis and studies have shown that when the CO2 rate goes up so does photosynthesis. So, I think you'd have the best results by providing CO2 to your plants from seedling to harvest.

Second: I now have a question about ventilation:
1. With the provided 4" ports on the HTG small grow tent; how should I configure, and what parts are needed for proper ventilation? I will have the 4" carbon filter/fan combo, but that is it. Also, My reflector wing does not have ports of any sort. (socket on one end and open on the other)

If you are utilizing a CO2 injector, then it will be best to use the fan and filter combo as a means to cool the lamp, whilst minimizing the exchange of air inside the tent! This means that you will need a Air Cooled reflector! This is a reflector that has a housing surrounding the lamp with a piece of glass underneath and flanges on both ends to connect ducting/fans , thus making heat removal possible. Or a glass Cooltube type reflector.
The Reflector you described sounds like a standard Lightwing or Waxwing reflector, also called a Batwing, which is not air coolable.
Fan and Filter will need to be "run through" the tent and consequently through the reflector at the same time. A total of 4 flanges will be needed, two per port sandwiching the tent material between to create a double flanged port on both sides. This allows you to connect the air coolable reflector to ducting and the flanges on the inside, while at the same time providing a mountable surface on the outer side to attach ducting to the fan and filter. Essentially the filter will be on one side of the tent, connected to the tent with ducting, then ducted to the reflector, then to the other flange, then finally back out to the fan. This completely segregates the air going threw all this from the tent! Complete heat removal, without affecting the CO2 levels inside the tent!
The Fan and Filter Combos can be used to cool the tent. However this will affect CO2 levels and I strongly recommend using a control unit! Essentially the filter is hung from the tent framework from the top. The ducting then runs to the fan which pulls air from the tent via the filter and exhausts it to a outside(of tent) area. This will clear the tent of CO2 within a minute or two!
Operating a CO2 injection system without a Controller unit is hard! Plus may end up costing more in the long run. Do a google search for "Using a CO2 injection system without a Controller". There are many "hands on" responses from a variety of forums! All mention that typically using a controller will reduce the need to replace CO2 tanks by half. So a tank that will last you 2 weeks controlling it with a timer will last 4 weeks if controlled by an actual CO level controller. Within a short amount of time, replacing spent tanks will cost you more than a control unit does!
Thanks and have a great day!


A Haiku on 12-12-12

Growing plants is fun

Light, Water and C O 2

Harvest and enjoy!


300 W LED vs. 400 W HPS

I got an E-mail from a reader that asked me not to use her name. She had been using a 400W HPS for many years, but decided to give LED’s a try, for the energy conservation, which is good for the environment, but the fact that LED’s don’t need new bulbs every 2 years, also means less resources are used, another financial and environmental benefit. She told me that she harvested a little bit MORE using the 300 W Tri-Band sold by HTGSupply. More importantly, she said she did not have to tie down the plants which used to grow overly tall and lanky when first put under the HPS. (Read my post on HPS and flowering) I love getting these E-mail’s as well as questions about growing. I enjoy growing and helping others and we can all learn from each other. If anyone else has made the switch from HPS to LED, let me know the results.  In my 2010 post comparing LED and HPS,  I suggested to use an HPS over LED for flowering, after using the LED's from HTGSupply, I now think LED's are comparable even during flowering

Good Growing,
Dr. E.R. Myers


Drying Herbs - Pictorial

This is one of three sections that comes with the Dry Net Ultra

Air drying herbs can be used to preserve all types of herbs, unlike freezing herbs which is only suitable for certain high moisture types. Many people enjoy their herbs year round by drying their herbs and keeping them in jars or airtight containers.

A simple method of air drying is to hang the plants with leaves/flowers still attached to the stems and upside down in a closet. This is how I dry garlic in the fall. For most other things, like the hops I grow to brew beer, I use the dry net.

Air drying is great because it does not cost a dime. I have happily been using the dry net for a few years, and I really like it. Simply spread the cleaned leaves or flowers one layer thick on a section of the dry net. This allows proper air flow, I have recommended to turn the plant material over each day to ensure even drying. It is best to do this process indoors away from intense heat and light which would cause the herbs to lose greater amounts of flavor. The dry nets fit inside most grow tents, so once you are done growing, you can use the grow tent to dry your herbs.

It took about a week to dry these hops in my spare room.  The temperature was about 68F and humidity ranged from 40-60%.   I kept the ceiling fan on 24/7 to promote moderate airflow.

Once your herbs are dried, you can store them whole (such as I have done above) or crumble the herbs (such as oregano) before placing them in an airtight container such as a glass jar. I put these hops in plastic bags and have them in the freezer.  Hops are best fresh, so I will be using these to add flavor on the next few batches of beer.
Good Growing,
Dr. E.R. Myers


Are You Wasting Money on Excess Nutrients?

One way to use the scientific method to save you money would be to do a little experiment to test if you are using/wasting too much nutrients. Many readers write in about brown spots or necrosis on leaves. While this has many causes, it is often a sign of over fertilization. (I have written about what to do if you do over fertilize your plants)

 Many people want to "max. out" and get the most of their plants, which is understandable.  But, good growers know the Goldilocks principle, not too much, not too little but just the right amount is what gets the best results and keeps you from being mired in mediocrity.

A simple scientific test would be to apply half the recommended fertilizer to one of your plants and the normal manufactures recommended amount to the rest. If you are growing several plants, you could also give a few plants 10% over the recommended fertilizer too.

After a week, you want to keep a journal about the plant being mindful of anything different about the plants. First, is one group of plants greener? Do you notice a height difference? Do you notice brown spots, or burnt leaf tips?

Once you get your data, you can then decide if you are using too much, too little or just the right amount of fertilizer.

Good Growing,
Dr. E.R. Myers


E-mail - Brown Leaf Tips

Ok so I was watering once a day when I woke up and since I got your message I have started watering with a little less water, but twice a day instead and that has taken care of the droopy leaves but the thing about the leaves with the brown tips is that I have not been feeding these plants any sort of base nutrients just like I was doing with the original roots organics soil, I am only giving the plants supplements like rhino skin and sweet with some B-52 and thats it, so its not that I am giving it to much nutrients, and its not root bound i just transplanted them into a larger pot a week ago. do you have any other suggestions of what may be causing the brown tips?

I have written one post about brown leaf tips before
I get brown tips sometimes too. The first think I would do is see what the humidity is. Indoors the humidity can go well below what it can outdoors. If you have a thermometer with humidity that has a high low, you just need to check and make sure the humidity is not below 50% all the time. Humidity can be very low if you are using an HPS or MH, but all lights generate some heat which will reduce humidity. If you are having good growth, this is a minor problem. You could water the plants a bit more, mist the plants, or sit open water in the grow room to increase humidity, but ALL of these can also increase mold and mildew problems.

If all the leaves at the top have brown tips (and you use an MH or HPS) it is most likely low humidity or high heat. It could also be a sign of low nitrogen. You could consider using a fertilizer like Roots Organics Buddha Grow. This has nitrogen but is not too strong, sounds like your soil is providing most of the needed nutrients.

I hope this helps, let me know if you have further questions about this or other topics...

Good growing,
Dr E. R. Myers


Herb Drying-2 -- Not all Herbs are Equal

Comparing one herb to another can be like comparing apples to oranges. Not all herbs are the same, nor should they be dried the same either. Herbs can be categorized as high or low moisture content herbs. This classification will determine which method of storage is best suited for each herb.

High moisture herbs naturally contain a higher level of moisture content. Such examples are basil, cilantro, oregano, parsley, mint and sage. These herbs are suitable for freezing or drying, although freezing is preferred. The real concern with high moisture herbs like Basil, tarragon, and mints is that they may mold and discolor if not dried quickly. Low moisture herbs naturally contain a lower level of moisture content. Examples of low moisture herbs are bay, dill, fennel, sage, savory, and thyme. These you have less concern with drying as long as you keep a good air flow in the area you dry them.

UV rays from the sun and moisture from dew and frost can discolor and severely reduce the quality of many herbs. This is why I recommend you dry herbs indoors in a large empty closet, attic, or unused corner of a room. Sage, thyme, summer savory, dill, and parsley are easy to dry. Basil, tarragon, and mints may mold and discolor if not dried quickly.

Good Growing,
 Dr. E.R. Myers

Click here to read my post and see pictures about Air Drying


Storing Herbs by Freezing

A friend of mine has been trying something new this year. They are storing their herbs not dried, but frozen. The freezing method is good for herbs with high moisture content. There are two popular ways to freeze herbs. The first option you basically store the herbs in ice by using ice cube trays and the second is using a flat surface such as a cookie sheet.

Ice cube trays -- Do not use ice trays that you use for ice, you will want your own separate trays for the herbs to prevent your trays from absorbing any of the herbal flavors.

First, make sure your herbs are clean. I usually chop up the herbs with a scissors but you can keep them whole, just make sure the herbs fit in the ice cube trays. Next, place the herbs inside each compartment in the tray. Try to keep the filling consistent, such as putting 3 basil leaves in each cube so you will know how many cubes to use later. Fill each compartment half way with water and put in the freezer until the cubes are mostly frozen. Fill the remainder of the cubes with water covering any basil (or other herb) which may have floated to the top of the water. Place back in the freezer and when completely frozen transfer the cubes into sealable freezer bags. Label and date each bag..
Flat surface freezing: This method is fairly straight forward and requires less steps, Make sure your herbs are clean. You then pat them dry with some paper towels. Next, spread them out on a cookie sheet or other flat surface, making sure not to overlap any of the leaves. If the herbs are overlapping, they will stick together when frozen and cannot be separated. Place the cookie sheet in the freezer. Once the herbs have frozen, place them in small freezer bags. Label and date the bags.
In the case of herbs such as rosemary, dill and thyme, it is best to leave these herbs with their stems intact and place in freezer bags with 3-4 sprigs per bag.
Good Growing,
Dr. E.R. Myers


E-mail - Brown Leaf Tips and Droopy Leaves

Hi, So I've been using the original roots organic soil, and I decided I would try out the Roots Organics Green Lite, and the plants that are in that soil, have been droopy and getting brown tips on the leaves. do you know what the problem is? If so what products preferably from advanced nutrients or roots organics product line can solve my problem?

Droopy leaves often means water problems; the green light has more perilite and drains water (higher permeability due to higher porosity). Did you completely saturate the soil the first time you watered? Does water come out the bottom when you first water? Does it do so quickly, like in a couple seconds? If yes then your soil is too dry (I almost never say that). The usual problem most people have is over watering, (which can also cause leaves to droop, and over time causes leaf yellowing) but I think the green lite is designed to be light so roots can grow easily through it, and unlike outdoor plants, indoor plants don't have to worry about running out of water. Tip the pots over a bit (not all the way) if they seem light, you are under watering. Another trick is to stick your finger into the soil/medium it should be wet when you stick it down to the second knuckle.

Some other causes of brown leaf tips are when the plants are root bound. Plants that are root-bound often have problems with brown or yellow leaves, so this is one of the first things you should check. If plant roots are growing in circles and look like a big mass or are growing out through the bottom of the pot, move the plant to a bigger pot.

Another problem is over fertilizing. Sometimes the minerals and nutrients in the soil cause leaves to brown. Chlorine, salt and fluoride can all cause leaves to turn brown. You could try using distilled water for a few watering, if you notice the new leaves do not have brown leaf tips, you found your problem. Using too much fertilizer may also be a culprit. Do a soil test if you think one of these issues might be your problem.

I hope this helps,
Good growing,
Dr. E.R. Myers


Yet Another Benefit of LED’s

LED lights come equipped with small fans to help cool the diodes as they convert electrical energy into light energy.  I have done tests on the LED's from HTGSupply.com, and you can see the pictures in past posts and I can attest that they are specifically designed for optimal plant growth. The fans help make the lights work great but has a side effect of increasing air flow.  Air flow will increase the photosynthesis rate, which will increase plant growth and yield.  I have written about what I think is the single best light, but I think I am becoming a convert, LED”s rock!  I also think LED's are great for growing in small spaces.  If you are looking for a new light or to expand your growth, the triband LED from HTGSupply.com is where I'd start.

Good Growing Dr. E.R. Myers


Watering Tip to Get the Most From Your Nutrients

In order to get the most from your nutrients you should always water from the top. Ideally, you want 100% of the soil saturated. The easy way to know this is to water the plants until some water comes out the bottom of the pot. If a lot comes out, you watered too much and should water less next time.  The nutrients that come out in the water are not always available to the plants.  You may be creating an environment for pests to thrive...

What I do is I alternate nutrient application with plain water (tap water). I water with the nutrient until a small amount of water comes out the bottom of the 2 gallon containers. (I can fit two containers into one tray which is nice). Then a day or two later, when the top of the soil is dry, I put the tap water into the tray about 2cm high. This is usually absorbed in a few minutes. If you still have standing water after half an hour, you will need to empty the trays, you DO NOT want to have your plants in standing water, it will kill the roots and eventually the plant. Yellow leaves are a common symptom of over watering/standing water.
By watering from the  bottom, the nutrients that are water soluable will be carried back up into the soil as the water wicks up.

Good Growing,
Dr. E.R. Myers


E-mail- The Right Size Container for Plant Growth

hey Doc - I’ve been stocking my flowering room with plants which have grown vegetatively for a minimum of 2 weeks. on the strongest plants selected for flowering the roots are typically matted up pretty good in the bottom of the 4 inch square pots I veg them in (from rooted cuttings). I do this because in a few different gardening books and stuff it's been mentioned that this root bound plant will more thoroughly fill out its new larger container's area of medium with more roots. do you think i might be better off using 1/2 gallon bags instead of the 4 inch square pots?

Thanks for the E-mail. I have written about potting up plants and container. The answer depends, if the roots are really matted up, meaning they are growing in circles and all twisted, then I disagree. The roots have wasted time and energy growing in a circle and you will have to cut and remove them to get good growth. I think the idea might be to get the plants to completely fill out the pot, and transplant it just before they grow in circles and around each other. I personally have found that bigger is better. When roots grow up against something hard, like a pot bottom, or a rock, they send a message to the plant that they can’t keep growing. If most or all the plant roots send this message, the plant will slow growth, and be a smaller plant with a lower yield. There is no such thing as too big a container. Well, sort of, the size constraint is not for the plant, but the space you have. If you can get enough plants in the area with ½ gallon pots/bags, I’d use that vs. the smaller pots.

Please read my previous post on containers and plant growth

Good Growing,
Dr. E.R. Myers


E-mail -Changing the Sex of Plants

I have heard of (but never seen) products supposedly able to "convert" female flower parts into male flower parts, effective ONLY on the area of the plant which gets sprayed. From what I’ve heard, this can be VERY advantageous when attempting to capture plant traits and breeding. If these products exist, do you happen to know where they are available? Are the products safe to use on edible as well as ornamental flowers?

I saw you asked this after reading my post on determining plant sex. Thanks for reading the past posts, I encourage everyone to do searches, I have been writing for three years and will gladly expand on any past topics as well as try to write about new questions.

I too have not heard of products that change the sex of the plant. If you apply plant hormones to parts of the plant, it will change that part of a plant. This might be hard for us mammals to understand, we are one sex only. Plants can be separate male andfemale (dioecious). like us, they can also have separate male and female flowers on one plant, or have the male and female parts together on a plant. Just like in us animals, it is hormones that determine the sex, testosterone will make boys and estrogen will make girls. If you apply a hormone to a part of the plant it will change that part of the plant only. How the hormones affect the plant depends first on its type of flower.  Hormones are also tricky because they can have a different effect on the same plant if applied at different times of the plants life cycles. Many different hormones are widely used, Hormones like gibberellins are involved with sex determination in some plants as well as other traits such as stem elongation. They can make plants produce seedless fruit, seedless grape, for example, wouldn't fully develop and mature without an application of hormones at the right time. These hormones can also force plants to flower, which is important in commercial greenhouses where the timing of flowering needs to be exact. I do not to use plant hormones too much, I do not have any reason why, I just have not.

Sorry I could not be more precise, if you send me the type of plant I could help more.  If you want to experiment, I do not think it will have any harmful effects on consumable plants, so long as you don’t consume the plant too soon after the hormones have been applied
Good Growing,
Dr. E.R. Myers


Coir Starter Plugs and Compost

As you know I like to compost and grow outdoors as well as indoors. There reason is that I just don’t have the room to grow everything I want indoors, and who can beat the cost of sunlight and rain?

I like to use the starter plugs for seedlings and cuttings.  Sometimes, the cuttings die, or I have plants that I harvest and still have the starter plug around the stem.  Last year I put several of the coir starter plugs in my compost pile. Several months later, they are still intact, but are very easy to break apart. I think in a couple more months they will continue to break down, and even if they do not break down on a molecular level, the plant roots, water and nutrients will still pass through the starter plugs. So, if you have some used starter plugs you have used a few times or some plant roots/ stem that still have the plug after you harvest, just throw them in the compost bin.

Click here for more information and how to order starter plugs

Good Growing,
Dr. E.R. Myers


E-mail - Using a Wick Watering System

hey Doc - have you ever experimented with any type of "wick" type feeding/irrigating? is so, did it take several set up attempts before it worked well? how many wicks should i be using in a 2 gallon container? I’m using 3 glasscloth wicks per container - this will be the fourth attempt I’ve made at this "wick" system and I’m about to give up 'cause i can't get it right.

I have used a wick system a couple times, when I had to go away on a trip and I was worried my plants might dry out. I used an actual wick for oil lamps, but anything that absorbs water will do old shirts and rags etc. You want the wick to be in as much contact with the soil as possible, so if you know you are going to use a wick, put it in the pot when you transplant the plant so that it runs down the side and along the bottom, maybe even wrap it around the bottom of the pot in a circle. Then fill in the soil mix. You want to make sure the wick is not pulled down on the top of the container too tight, this may keep the water from flowing. Make sure the whole wick is saturated and put the other end in the bucket with water. The water should wick or diffuse from the container of water to the soil. It might help to mix in with your soil some vermiculite or coco coir that will help absorb the water from the wick.

I hope this helps,
Good Growing,

Dr. E.R. Myers


Improving Plant Growth by Knowing Your Soil.

It is important to understand soil, in order to be a good grower. The first thing to look at is soil texture. This is simply the percentages of sand, silt and clay that make up any soil. The size of the particles is important in how much air and water will be in a soil type. Sand particles (range from 0.05-2mm) are the biggest, so they will encourage soils to drain allowing oxygen to get to the roots. However, without watering the plants, sandy soils can dry out and leave the plant without water, which is crucial for photosynthesis. Clay particles are the smallest, (less than 0.002mm) so water has a hard time moving through clay. Also, clay had a negative charge so water and nutrients that have a positive charge ‘stick’ to clay. This means clay soil’s hold on to water (and nutrients) so they help keep a soil moist. However, clay soil’ can have slow or no drainage which means the soil will become waterlogged (all the pores full of water) and the roots won’t be able to get oxygen and the plant will not grow and will eventually die. The amount of pore space in most soils is usually about around 50% for all mineral soil types. (Porosity – actual volume of spaces between soil particles) The rate that water moves through soils is called permeability. (Permeability – rate through which water moves through soil). It might seem that porosity and permeability are the same, a lot of pores means the water will move quickly. This is not the case. Soil’s that have a lot of clay, have a lot of pores, but they are very small pores, so the permeability of clay soil’s is very slow. Movement of air and water through the soil regulate the growth and type of plants that are able to live there. Therefore the best soil, called a loam, has a percentage of sand and silt and clay that allows for plants to get oxygen and water to the roots.

Summary clay – made up of small particle that fit tightly together = small pores
lots of pore space, but water doesn’t drain well b/c it’s held tightly
sand – large pores, plenty of aeration, dries rapidly and easily loses nutrients
loam – good mix of water holding ability and drainage

Note: A soil with as little as 20% clay will behave as a clayey soil. A soil needs 45% to 60% sand to behave as a sandy soil. In a soil with 20% clay and 80% sand, the soil will behave as a clayey soil

If you have a ‘heavy’ clay soil, you can add sand, if you have a sandy soil, usable clay is not easy to get, but you can add organic matter in the sustainable forms of compost, coco coir, and manure or try adding the mineral vermiculite which will also help soils’ to hold water.


E-mail - Light Mover vs. Two Lights

Doctor Myers,
  Can a 1000 watt light on a mover be as good as 2 1000 watt stationary lights in a 5 ft by 10 ft area

You will have twice the illumination (and twice the cost to buy, use twice the electricity and have twice the heat output) with two lights.  The idea behind a light mover is to get a little more grow area from a single light source, and the area you have might benefit from a light mover that moves the light along a track the 10 foot length.   Without seeing your grow area I would guess that two lights might be too much for that area, depending on how you can handle the heat.
A light mover will increase the grow area, but the maximum rate of photosynthesis will only occur when the light is directly over the plants. The idea is that like a plant growing outdoors, some days are cloudy so plants won't die if they don't get the maximum amount of light. However, the real benefit to indoor growing is that EVERY day is full sun, and the grow medium is always moist, which would give you maximum growth and yield. Light movers can increase the grow area but you eventually get to a point where as the grow area increases, the yield per area, will decrease because the plants are not getting enough light to perform photosynthesis at the maximum rate....

If you are looking for maximum yield, and can deal with the heat and electricity usage, you will do better with two lights.
Good Growing,
Dr. E.R. Myers


E-mail - Getting Started with a Grow Tent

  I have a 4x4 grow tent, what do I need to get started?  What about ventilation.

I would first recommend that you and all HTGSupply.com customers contact the shipping manager Perry at Sales@HTGSupply.com for all questions about equipment. I have used some of the great HTGSupply.com products, but he has worked with more, and does so on a daily basis. He is my go to guy when I have an equipment questions.
If you are growing plants for flowers or fruit, I would recommend a 400 HPS, but you will have to have an air cooled version for the grow tent. You could also try a 300 W LED. You might not need to vent with an LED, but that will depend on how big the plants you are growing will get. Heat rises, so with the LED you might get temperatures at the top of the tent in the 90’s which are not going to kill your plants, but will reduce yield and overall growth.  If you are growing say basil and can have the LED about 3 feet above the plants, the temperature should not be a problem.

I recommend all first time growers start off with soil, it is easy to get, and is the easiest medium for growing since it is what plants naturally grow in. I recommend a minimum of one gallon of grow medium space (size of the pot) for every foot of plant height. I usually use 3-5 gallon buckets, you will not have problems if you have a container that is too big, as far as plant growth. You may want to try different sizes to get the best size for your grow tent.

Good Growing,
Dr. E.R. Myers


E-mail - When to Start Adding Fertilizer to Seedlings


How soon should I give my plants fertilizer, I have read a lot of posts about nutrient burn and over fertilizing and I don’t want this, but I want my plants to grow great.

Thanks for your question. As I often say, it depends. It first depends on the medium you are growing in, soilless mediums will need nutrients from the first watering. I often suggest ½ to ¼ what the manufactures suggest for the first few watering. Once the plants are established and obviously growing, you can then go to the manufactures suggested amount of fertilizer. To be honest, I think most of the time fertilizer burn is due to people trying to get more out of their plants by adding more fertilizer. This is like saying taking more vitamins will make you healthier, it won’t. In fact some vitamins, just like plant nutrients, are toxic at high amounts.

If you grow in soil, I often recommend using straight water for the first watering or two, then using ½ the manufactures recommended amount until you see visible growth.

It also depends on the plant you are growing. A fast growing plant will need more nutrients than say a cactus. A large plant will use more nutrients than a small plant. You will need to evaluate for yourself what type of plant you are growing.

If you do over fertilizer, I have written a post about how to deal with over fertilizing your plants.

Good Growing,

Dr. E.R. Myers


E-mail - Composting Questions

I just finished reading your first article about compost/composting, where you explain how to do it. I gladly inform you that after doing more than a little reading on the subject, your article has helped me achieve a higher, more comfortable level of understanding

As far as manipulating the compost pile goes, I would like your opinion of how much wood ash I maybe should add to counter act a 5 gallon bucket of coffee grounds (and a much lesser amount of vegetable scraps and egg shells) per month - into the compost pile. my pile is 4' x 4' x 4', contained by pine boards (they may not last a decade, but by the time I need to rebuild it maybe i can afford to use cedar). i do add all my grass clippings, fallen leaves and garden wastes - and i mix it up every 3 - 4 weeks. I wet it down with rain water collected in a barrel (which brings up another question I would like to add: could I use the waste water from my RO filter to water the pile occasionally since the chlorine has been removed?) every 2 weeks, as it doesn't get much rainfall. I purchased a product from my local feed store called "compost maker," but have not yet used it because I cannot find anyone else I trust to offer me an opinion.

To further complicate my question, I would like to pick your brain (if I may) about adding my poultry's manure to the pile (duck and chicken). The manure easily available to me is usually dry, but not rotted. I will have the 4 inch thick layer of pine/cedar shavings mixed with the manure (which supposedly has already rotted somewhat because I employ a "deep litter" system in the coop, and will need to change it this fall. The bedding/manure has been on the floor of the coop for 2 years. What might be the best way to incorporate this bedding into the pile (other than mixing it in) - the coop floor is 8' x 8' and 4" thick.

Thanks, you have some great questions. Wood ash is basic, and coffee grounds are acidic, but it would be hard for me to give an exact measurement. I know adding too much wood ash can kill a compost pile. (. By kill I mean it will kill off the beneficial organisms that grow in the compost. Yes, not only does compost reduce environmental waste, increase nutrients, especially micronutrients, it also adds beneficial organisms to the grow medium. What more could you want?) I don’t think I’d add more than a 5 gallon bucket of wood ash to your size pile over a year. You want the pile to be slightly acidic so coffee grounds are not too much of a problem.

Adding your water is fine, so long as you don’t make the compost pile too moist. I tend to build bins, just like you have done.  I tend to make a lot of compost, and most containers are too small, and if you look at my post on composting, you can see they are probably cheaper than one’s you buy.

I think you are going to have to mix in the bird manure. If it is over 2 years old, it should be composted a bit already. This is going to be a nitrogen source, so you will want to have equal parts of brown material like dried plants/leaves or soil. You could try to add a gallon bucket of the manure every time you mix the pile. If you don’t notice any smell or anything funny with the compost, you can add more than that. I have not used chicken or duck manure, so I can’t talk from personal experience here.

Thanks, and keep up the great work!
Good Growing,
Dr. E.R. Myers


E-mail – HPS and Internode Stretching: Is It Time for an LED or Conversion Bulb?

Dr Myers,
    Is it true that hps bulbs cause more Internode stretching if the spectrum is not balanced with blue? do you believe an LED could be used to provide blue light to the flowering plants effectively enough to decrease Internode stretching?

I have only used hps bulbs so far. The 18 month mark came and I replaced all 3 with new htgsupply hps bulbs just like the ones that came with the light kits, and I feel this "pang" of wondering if i could get better results by either adding a halide conversion bulb or adding LED's. I understand the only way I can find out would be through scientific experimentation myself but my emotions keep me from spending the money on LED's. I am afraid to swap out 1 of the 3 hps bulbs with a conversion bulb because I don't yet have a light mover and the conversion bulb would light only one 3' x 3' bed - and that doesn't seem like an actual change to the spectrum in the entire room would take place. Is it time for me to bite the bullet and start the experiment or do you think I’m way off track here?

Thanks for the E-mail. Yes, HPS will cause internode stretching in most plant species. This is due to the light output being more in the yellow/red range, and a lack of blue light. However, if your plants are flowering, I’d not use a conversion bulb, they have a much lower output of light. (Read my post on flowering and HPS vs. MH)You may want to bend or prune your plants. You want the maximum amount of light to maximize your yield. If you are using this room for vegetative growth, then you may want to use a conversion bulb, or get an MH, which is much better for vegetative as far as internode stretching (there is no problem with MH’s)  but and HPS putts out a lot more light intensity than an MH.

As far as LED’s, you could put in an all BLUE LED to correct the problem. You could get 2-3 panels and put them beside the HPS you already have to cover the grow area. This blue light won’t need to be as intense; you just need to increase the blue to decrease the internode stretching. A Tri-Band LED would also reduce the internode stretching. I have only used a 90 and 120 Watt LED, but I am going to use a 300 W from HTGSupply.com this semester, and I am assuming it will be compatible to a 400 W HPS. I will let you and other readers know.

You may want to think about a light mover, since you have multiple lights. You could increase the grow area, and at the least you would get better growth on the peripheral areas. Without moving the light or plants the plants on the edge of your grow area won’t get the optimal amount of light. You could then put an LED or MH in the room and move it around with the other lights. I think this is the best option, but it is also the most expensive one.

Good Growing,
Dr. E.R. Myers


What To Do If You Over Fertilize Your Plants

If you know you have acute (very serious symptoms) of over fertilization (nutrient surplus) you need to act fast to save your plant. If you are growing hydroponically, empty the reservoir and start over. You may want to flush the medium once before refilling the reservoir. Read on for soil and soilless mixtures.

First, leach the grow medium. Leaching means you basically flush or run water through the mixture. Nutrients will be carried by the water and into the tray you use to catch water over flow. You should water your plants until it runs out the bottom into the trays. You will need to empty the trays a few times, so it is a good idea to have a spare tray to put the plant in when you empty the tray. (The plant will continue to drip out water so you want to have a second tray to put the plant in to keep down on the mess).

I use tap water, but you can leach the growing medium with a professional leaching agent to leach away metals, calcium, sodium, chlorides and other compounds, which can build up in the growing media. This leaching agent will bind to the nutrients and a good one will help remove nutrients that are not water soluble. Check the HTGSupply.com website for specific products.

Second, you need to check the pH if you are using a soilless mixture. Overwatering and leaching of nutrients will affect pH. If you are using soil this won’t be such a problem. Adjust the pH to the proper range for your plant.

Third, I would then administer a beneficial product like stump tea to the soil. The microorganisms will help to bring to balance any remaining nutrients and those lacking due to leaching. You could also use a high quality vitamin B-1 product such as Superthrive (1 drop per gallon). If your plants have been in the medium for a few weeks, you should also use a ¼ strength organic fertilizer to supply some nutrients for a week or two. Once you see good grow again increase to the manufactures recommended strength fertilizer.

You also may want to reduce the light intensity for a few days. If you are using an HID or LED you may want to raise the light a bit. Most indoor growers have the lights as close as possible to the plants to maximize absorption. But if you over fertilized your plants, they are stressed so reduce the light intensity and let the plants recover. Or, if it is not a hassle use fluorescents about 1” from the plant tops for a few days. The low output but excellent light frequencies provided by fluorescents are easy on plants.
You won’t see results instantly, it will be days. But you should see new growth lacking the symptoms.
Perhaps most important, write down how this problem happened and take steps so that it does not happen again.
Good Growing,
Dr. E.R. Myers


Seed Stoage - Revisited

It is a good idea to save your seeds especially if you grow outdoors and your plants are producing seeds as summer comes to its end.  Plant breeding is also a fun hobby, and storing seeds safely to maximize the number that germinate is an important part of plant breedingPlease read my previous post on seed storage.

Good Growing,
Dr. E.R. Myers


How to Correct pH With Soil and Soilless Mixes.

This post deals with soil mediums but i would be a good idea to read related posts for background material.  I have written about checking the pH with hydropoincs as well as  correcting the pH in hydroponics.

Once you test the pH, if it is below 5.9 or above 7.0 you may want to adjust the pH. One way to adjust for minor pH changes is to change the pH of the water you use to water your plants. You can buy pH up or down from HTGSupply.com and use it like in a hydroponics system to water your plants.

If you have a severe problem I recommend you transplant or pot up the plants using new soil. This often is all that is needed. However, if you can’t put your plants into a new bigger container you can remove the first inch or so of soil,( try to minimize root damage while doing this) and sprinkle lime into the pot, at a rate of 1 teaspoon (5 ml) of lime per gallon of soil. Give your plants a good watering to work the lime throughout the soil. You can replace the soil you removed earlier, but I have found adding new soil on top is better. Put the old soil in the compost pile.

Check the soil pH next time your plants need watering to check that everything is fine. You should only need minor adjustments to the water if any.
Good Growing,
Dr. E.R. Myers


How To Measure the pH of Soil or Soilless Mediums.

I have written about checking pH for hydroponics growers.  Soil growers have less problems with pH than people growing with hydroponics, but good growers also measure the soil pH to see if it in the optimum range for growing the best plants. Once you grow successfully, you need to keep trying new products and techniques. Keep testing things with scientific tests so you don’t get mired in mediocrity.

You will need to wait until your medium is dry and ready to be watered. Use the same water you use for your garden and adjust the pH to around 7.0. You must know the exact pH of the water going into your soil, so really anywhere from 6.5 – 7.0 will suffice.

Second, place your plant/container in some sort of tray to catch the runoff water, and water slowly (with your pH known water) until the water drains into the tray.

It’s the first drops of water that will give you the best reading of your soil, so make sure to water slowly. Then, remove the pot from the tray to eliminate excess water entering the tray. It is a good idea to have a second tray to put the plant into as more water drips out. Then, perform the pH test on the runoff and compare it to your initial test. (You can get pH tests kits at many places including HTGSupply.com)

The results of the runoff test will likely be lower than your starting value of 7.0. If this is the case, a small drop of 0.5 pH to 6.5 pH (example) would be ok and your soil needs no further alterations at the moment.

I would recommend doing this for all plants in your garden, but if you get about the same reading for all plants the first time you do this, you may only need to test one or two plants each time you check the pH. I’d check the pH once a month or at a minimum at the beginning of vegetative flowering stages of growth.


How Are Nutrients Lost From the Soil?

I get a lot of questions about what fertilizer is the ‘best’ and there is a lot of buzz online about various fertilizers and their myriad of benefits. So, one thing you want to think about is once you add fertilizer, how will they be lost from your soil or grow medium.
The first way to lose nutrients is root absorption. This is what you want, the nutrients to go into your plants to promote growth and increase yield. I have written about factors that can limit growth and good growers know that too many nutrients are just as bad as too few. This Goldilocks factor of biology is why you need to do scientific tests to see what amount of fertilizer you should use. ALWAYS start with the manufactures suggestion; they should have done some tests to give you this starting point. Some plants will do better with a bit more, others may actually grow better with a bit less fertilizer. If you do not get improved growth with more fertilizer, then that can save you money, and prevent nutrient build up over a long time.
   Another way for you to lose nutrients is through leaching. This is when water soluble nutrients are dissolved in water and as the water moved down and out of the pot (or out of the root zone outdoors). Many growers do a ‘flush’ after they are done with vegetative growth; the idea is to wash out any excess nitrogen which can interfere with flowering. This is why you want to waer your plants only when the top layer is dry, so they can use the nutrients in the soil, and you only want a small amount of water to run out the pots when you water. If you notice a white ring on the trays that catch water overflow or on the bottom of your pots, that is most likely salts/fertilizers residue. This is a sign of leaching. Leaching is not a problem with hydroponics since the water is cycled over the roots many times, but you do have to deal with the pH with hydroponics or the nutrients will be unavailable no matter how much you add to the solution. If you are growing outside, another way to lose nutrients is erosion, when pieces of soil are washed away in a rain storm or blown away by wind the nutrients attached to that soil are lost too.

Good Growing,
Dr. E.R. Myers


E-mail - Using Small Pots for Big Yield

     I have read your posts in growing in small spaces. I do not have a lot of space and I was thinking if I keep the plants in small pots and keep them well watered, I will have more plants and get the biggest harvest from a small area. I am going to try to grow plants from veg. through flowering in 1 gallon pots. What do you think, any suggestions you have would be great.

Thanks for the E-mail and reading the other posts, it makes me happy to know I can help. Theoretically you are right, if you keep the soil moist but not soggy and give the plant all the nutrients it needs you should get good growth. That is the basic idea of hydroponics. However, if you grow in soil, it will be harder to keep the whole soil moist, but not too moist (see my post on water retention in soils). Also, once the roots hit the container edges, they will be restricted in growth and restricted root growth means restricted plant growth. You might want to try a bubble boy or two instead of using small pots. I think you might get a bigger yield with that vs. several small containers. This depends on the plant species you are growing and light you are using, you did not mention that. I do not know what type of height restriction you have. If you do not have a lot of height, I’d recommend a T-5 fluorescent or a LED from HTGSupply.com.

Last, you could do a scientific experiment and grow a few plants in the gallon pots, and try others in a 2 gallon pot. I find most growers use 2 gallon pots or larger when trying to get fruit. Many plants need to get a certain size before they flower, so if you are growing larger plants, you might want to go with 2-3 gallon pots.
Let me know if you have any other questions, and how things turn out,

Good growing,
Dr. E. R. Myers


Water Availability in Soil Mediums II

 I will continue to talk about water availability in soil mediums. Most soils have about 50% pore space. This may surprise you. It is the pore spaces that are important and various mediums will increase or decrease the pore space, meaning they will increase or decrease the amount of water a soil/medium can hold. Please see my posts on sand, perilite, vermiculte coir, coir and soil  and more to determine what you should be adding to your medium.

When soil is saturated it means, all the pores are full of water, but after a day, all gravitational water drains out, leaving the soil at what is called field capacity. Plants then draw water out of the small pores which hold the water against the force of gravity. The longer the soil goes without water the greater the difficulty the plants will have at getting water, until no more can be withdrawn. The soil is then at what is termed the wilting point and without water additions, plants die.  Like I tell my students, most things in Biology go by the 'Goldilocks Principle'  Not too much, not too little, but just the right amount is what is needed.  You don't want a saturated soil, you will get reduced growth and often have yellow leaves as a first sign you are aver watering.

The amount of soil water available to plants is governed by the depth of soil that roots can explore (the root zone) and as I said the nature of the soil material.  Taller containers will allow roots to grow deeper.  A wide short pot may have the same volume, but it won't hold as much water once the gravitational water is gone.   Because the total and available moisture storage capacities are linked to porosity, the particle sizes (texture) and the arrangement of particles (structure) are the critical factors. I will discuss these terms in the next post..

Good Growing,
Dr. E. R. Myers


E-mail - What is a Lumen, and How Much Do I Need

Hey Doc,

    How many lumens per square foot should I have in my garden? What is a lumen anyway?

A lumen is a unit to measure light coming from an angle or a source (like your grow light). A lux is another unit of measure, it takes into consideration area. It is complicated, but basically the larger the area you consider, the lower the lux you get with the same amount of lumens. Lumens are the output, lux is a measure of that energy over an area. There are two types of lumens, luminous flux which measures light that is visible to the human eye, and power or radiant flux, which measures total output. If you are going to measure your grow lights in lumens, you want to use radiant flux. Plants and the human eye both have pigments so we can see color, and plants can absorb lights energy. We have different pigments though, so comparing what we ‘see’ as color, to what plants need to drive photosynthesis is, well comparing apples to oranges. It does not correlate to good growing!

I do not like the lumen (or lux) for measuring light for plant growth. One reason is that lumens would include green light in its measurement. However, plants do NOT absorb green light, they reflect it. So, you could have a grow light that emits a good percentage of its energy in the wavelength of green light, and it would register a high lumen output, but the electricity you are buying to run this high green output light is not available for plant growth.

Good growers may want to read my post comparing light intensity of MH and HPS


How to Use Beneficial Products for Optimal Results

When you add beneficial organisms you are altering the rhizosphere. You want to increase the number of organisms that benefit your plants growth, but to do this you need to get the microorganisms to the rhizosphere.
Make sure you saturate the soil completely. You would be wasting the product if you just water the top of the soil and the organisms cannot get in contact with the plant roots. Also, do not over water, you want the water/product to come in contact with the plant roots, but not sit in the trays under your pots.
Using Beneficial’s can mean more nitrogen fixing bacteria, or more chelation chemicals that help with the absorption of nutrients with your plants or various fungal mycorrhizal species with help plants to absorb nutrients from the soil. I have personally tested and used the Roots Organics and Stump Tea sold by HTGSupply.com. If you have not used these products, I highly recommend doing a scientific test  .Use it on some plants and not others of the same type, and compare growth, yield flavor and color of your groups to see if there is a benefit. I know you will be happy you did.
Good Growing,
Dr. E.R. Myers


How Late Can You Put Plants Outdoors and Still Get a Harvest?

I had an E-mail about starting plants later in the summer, but the sender did not want his actual E-mail used on the blog… The sender had started some seeds indoors and life had gotten complicated and the plants were still in small pots under a fluorescent light on/off - 20/4. It is late June and the first frost won’t be until early October, assuming a normal year.

It is a great idea to start your plants indoors for an outdoors garden.  You can still put your plants out in late June or even a bit later in the summer. The problem is your plants will be smaller so you will get less of a yield. It would still be great to put out a tomato or pepper plant in July and only get 2-3 peppers than throw the plants on the compost pile and get no peppers.
Some things to keep in mind... If the plants are root bound, you will want to break up the roots to they do not keep growing around in circles. Some people suggest using a clean sharp knife and making 3-4 incisions along the sides. I tend to break the bottom of the root mass up so the roots grow down.
You will also want to keep the plant watered well, one because you will damage the roots when you break them apart but also secondly in your situation I assume the plants have a pretty small root system compared to the above ground biomass. It will take a couple weeks for the roots to grow deep enough to support and supply the plant with water.
You may also want to space your plants CLOSER together since they will not get as big as normal. When growing indoors, it is possible to increase yields by growing lots of smaller plants vs. a few large plants. I do not know if this is the same for outdoor growing, since plants do not have the special limits they do indoors it would be better to start plants early and have them get as big as possible.
You may be tempted to add a high nitrogen fertilizer, but this may lead to the plant growing vigerously in vegetative mode and you may not get flower/fruit set. I would still give the plant some nitrogen, but I would recommend the phosphorus be the highest number.
Good Growing,
Dr. E.R. Myers


Soil and Water Availability I

The medium you use, affects the water holding capacity which will then affect the rhizosphere and over all plant metabolism.. One of the main functions of soil is to store moisture and supply it to plants between watering.  Knowing a soil's texture will help you know what you need to do to improve your soil.  Good growers know that evaporation from the soil surface, transpiration by plants and water drainage by gravity combine to reduce soil moisture between water applications. If the water content becomes too low, plants become stressed. The moisture storage capacity of a soil provides a buffer which determines a plant’s capacity to grow at an optimim rate.
The number one reason plants do not do well or die indoors is that people overwater them. Yes you can love and care for your plants too much.
The problem with over watering is that there is no longer oxygen available to the roots. Roots need BOTH oxygen and water, too much of either will slow growth and limit yields

High H20 = low oxygen, root physiology slows and stops. You will notice leaf yellowing
Low H20 = lower rate of photosynthesis, leaf physiology, specifically photosynthesis will slow and stop as water becomes unavailable to plants.
The amount of water held in a soil is a function of the pore size (cross-sectional diameter) and pore space (total volume of all pores) A balance results due to pore space - big pores drain freely small pores retain H20, a good medium will have varying pore sizes.

Pores > 60 uM - gravity controls H20 in pores - GRAVITAIONAL H20
Very important in air exchange in soils promoted by sand perilite and small stones

Pores 0.1 uM to 60 uM primary source H20 for plants - CAPILLARY H20
Capillary forces hold H20 against gravity so they provide water to plants over lonter perionds Vermiculite,  small perilite particles and organic mater like coir or compost

Pores < 0.1 uM hygroscopic H20 unavailable to plants (held too tightly) Clay

1.Gravitational water is found in the macropores. This water moves through the soil due to the force of gravity. It moves rapidly out of well drained soil and is not considered to be available to plants after a few hours or a day.
Too much gravitational can cause plants to wilt and die because gravitational water occupies air space, which is necessary to supply oxygen to the roots. If you let your plants sit in water, the gravitational water can not drain.

2.Capillary water: Most, but not all, of this water is available for plant growth. Capillary water is held in pores that are small enough to hold water against gravity, but not so tightly that roots cannot absorb it.
Capillary water is held by cohesion (attraction of water molecules to each other) and adhesion (attraction of water molecule to the soil particle).

3. Hygroscopic water: This water forms very thin films around soil particles and is not available to the plant. The water is held so tightly by the soil that it cannot be taken up by roots. Clay will contain much more of this type of water than sands because of surface area differences.

The reason you want a variety of pores in your medium is because as the water is withdrawn, the larger pores drain first. The finer the pores, the more resistant they are to removal of water.  You want large pores to drain quickly so your roots have oxygen, but you want small pores to hold water against gravity and provide your plants water for photosynthesis.

Please read my next post on water availability in soil...

Good Growing,
Dr. E.R. Myers


How to Use Beneficial Organism Products for Optimal Results

When you add beneficial organisms you are altering the rhizosphere. You want to increase the number of organisms that benefit your plant. To maximize efficiency you need to get the microorganisms to the rhizosphere, so you need to saturate the soil completely. You would be wasting the product if you just water the top of the soil and the organisms cannot get in contact with the plant roots. You also do not want to over water your plants and have the microorganisms in the water trays under your pots. With a hydroponic system you want to make sure you water the product directly on the roots. You may get the organisms into the rhizosphere via water recirculation but I would try to make sure you maximize exposure when you first water.

Using beneficial bacteria/microorganisms can mean more nitrogen fixing bacteria, or more chelation chemicals that help with the absorption of nutrients with your plants or various fungal mycorrhizal species with help plants to absorb nutrients from the soil. All of there are found in the roots organics and the stump tea sold by HTGSupply.com. If you have not used these products, I highly recommend doing a scientific test. Use it on some plants and not others of the same type, and compare growth, yield, flavor and color of your groups to see if there is a difference and hopfully a benefit from the new product.

Good Growing,
Dr. E.R. Myers


See the Results of Using Beneficial Microrganisms

I have some pictures in this post so ou can see with your own eyes the benefits of using  beneficial microrgansims.  There was improved plant growth rate.  This increased rate of growth continued throughout the plants life cycle.  Plants with the microorganisms were larger, produced more fruit at a faster rate compared to those that did not have any beneficial microorgansims.  They say a picture is worth 1000 words, and seeing is believing, so here you go.  I used plant height as a measure in this post, but there are a number of different things you can measure to test the affects of products on plant growth

You can see the benefit already at the seedling stage  The seedlings on the left (With beneficial organisms added to the soil) are statistically larger.  Remember this is a scientific experiment, all other conditions (light, water, temperature, medium grown in etc.) are the same, so the reason for the difference is due to the addition of microorgansims like Stump Tea.

Sorry about the yellowish color, these plants are under a 600W HPS with a sun soaker reflector.

 You can see the benefits continue, the group on the left has shown an increased growth rate.  The plants on the left have an aditional node and are about 2cm or about an inch taller

You must always have a control group, and you must take careful measurements to determine if a product is actually improving plant growth.  Don't be afraid to try a new product, but test it to see if it worth it.

Good Growing,
Dr. E.R. Myers


Knowing about the Rhizosphere will Improve Plant Growth II

This is the continuation of a post on the rhizosphere.
The rhizosphere can be thought of as a small ecosystem with several feeding (trophic) levels.

1) Plants elucidation (excretion) is the base of the food web for most organisms in the rhizosphere. Plants secretions are food for many microorganisms. If you are providing the optimal amount of light and carbon dioxide, plants should be conducting photosynthesis which will fuel all the physiological reactions needed for plants to improve the rhizosphere with their secretions.

2) Bacteria (some nitrogen fixers, others cycle nutrients) These are the organisms that eat the secretions, the herbivores if you will. Some of their secretions are nitrogen in a usable form for plants, or other nutrients. These are the types of organisms found in products like Stump Tea and Roots Organics.

3) Microfauna are organisms usually protozoans that are less than 0.1mm. These often eat bacteria, these would be considered the carnivores of the rhizosphere ecosystem. These organisms can eat bad bacteria, and their secretions can benefit plants as well. They often convert nitrogen and other nutrients to a more usable form by plants. To be honest there is a lot yet to be learned about all the possible interactions that occur in the rhizosphere.
There are also symbiotic relationships in the soil. Mycorrhizae fungus can form a relationship with plants so that the plants provide the fungus carbohydrates (via photosynthesis) and the fungus provides nutrients to the plant since it has smaller ends (hyphae) that can get nutrients from the soil better than plant roots.
There are always exceptions in biology, and one should always do scientific experiments but one thing has been shown to be true: Soil’s with increased biological diversity have increased nutrient cycling and stability. This means you should try to add many beneficial organisms to your soil, there is no real down side to it.
Please see my post with links to various products that increase the beneficial organisms in your soil or hydroponics system.
Good Growing.
Dr, E.R. Myers