E-mail - Comparing HPS and LED

I just read your article on LED vs. HID. My question is side by side how much is the yield affected comparatively? When grown using 300w led vs 400 w hid in flower stage
Sent from my iPhone

Hello,
  I have not done a "side by side" experiment, but I do agree with my article comparing HPS and LED, that LED's are comparable to HID's, even in flowering.  I have used a 400 HPS and a 300 W LED in the same grow area at different times with the same plant type.  They were comparatively equal.  The plants were different, (same strain so genetics were the same)  The plants under the HPS were bigger, with longer node length which was due to both the increase in yellow, and the fact heat was a problem, the temps were in the 90's when the light was on.  Under the LED, the plants were more compact due to more blue light and also that with the LED, the grow area never got above 85F.

The plants were bigger under the HPS, but I'd say that when it was time to harvest there was not much difference between the two.  If you are using a 600 w or 1000 w you might want to use two LED's to get the same area coverage.  The LED's are more focused so when you get into the larger sizes of HPS with their reflectors, they can cover larger areas.
Good Growing,
Dr. E.R. Myers

E-mail - Is a LED the Right Light?

I am in need of a grow light.  I had bought a 90W 3 band ufo on another site claiming to out preform a 400W HID and cover a 4x4 area, but after several months I am very unimpressed.  HTG recently recommended the 430W 7 band LED as being able to cover a 4x3 area.  This seems to mean to cover the same size area I could either run a 400W MH (which I already have a ballast) or the 430W LED.  I switched to LED in the first place because my utility provider is very expensive compared to others around.  Currently what do you believe would be the best option?  In several of your old posts you recommended the tri band LEDs, but why not the 7 band?  I will need to ventilate either way so that is not an issue.  The HID lights are much cheaper, so what makes the LEDs so much better aside from longer life.  I want the ability to cover about a 4x4 area, but be as energy efficient as possible.  What are your thoughts?

Thanks

I agree with your thinking.  The LED, will cover that area, you can keep it 3 feet or a bit higher above the plants to cover more space.  White walls will be your best bet to increase reflection; don't forget to paint the inside of the door too.

The 7 Band 430 watt LED  uses about the same electricity, as a 400 w MH but the LED will grow plants great.  If energy conservation is a priority, you could get away with a 240 watt LED, but you might not be able to fill all your grow area. I can tell you any LED from HTGSupply.com will be better than a MH, especially if you are going to flower your plants.   With a MH or HPS, you will need to replace the bulbs every couple years, if you want to get the most from the lights.  LED's don't have this problem; they last for 80,000 or more hours with little to no loss of output.  So, the LED will save you on electricity and will give you great plant growth for years without having to spend any more money on bulbs.

I hope this helps, E-mail me with any more questions,

Good growing,

Dr. E.R. Myers

E-mail - Slugs in the Grow Tent!

Doc, 
I have a grow tent in my garage.  I found slugs in my grow tent, what do you recommend as I plan to eat my plants, so I don't want to use anything toxic.  I am growing in a soil mix I got from HTG

Hello,
  The slugs are getting in from somewhere, you may have a small hole etc. in your garage.  They are most likely nocturnal, so you could go out at night with a flashlight and look for them.  Also, slugs leave a slime trail, which helps them move, but it also allows them to find their way back to the food, look for a slime trail coming out of your grow tent and you might be able to follow it to where they are getting in.

Slugs are easy to control, you just have to sprinkle sluggo all around the grow tent.  This is made of iron phosphate, so you can put it in the soil around your plants, and even around the outside of your garage.  Just make sure you put a lot of it down, you want to make sure the slugs crawl over it.  The sluggo will be absorbed by the slugs, and it interferes with an enzyme in their digestive system and they no longer can eat, and they die.
I have written a post about slugs and snails with pictures of damage, if click here if you want to see it.
Good growing,
Dr. E.R. Myers



Click here to order Sluggo!

Here is a picture of a leopard slug, it does not have its antennae extended.

E-mail - LED, Grow tents, humidity and temperature

Hi Doc,

I read your blog about led's and grow tents temps. I have a 39x39x79 AgroMax tent with  a 120watt Tri-BandLED. When I first set it up I was getting temps in the mid to upper 80's with very high humidity. I was afraid it would be too much for my plants so I turned on the 6" inline fan filter combo and it reduced it some but I didn't want to run it all of the time. I also have a smaller fan which is on a timer with the led and the inline fan. After that I turned down the intensity to the led and have turned off the inline fan and am now getting temps in the low 80's with about the same humidity. I also have the timer set for 18/6. What do you think? Should I go to full intensity at 24/7 or should I stay where I'm at? I don't want to damage the plants with high temps and humidity. This is my first indoor growing attempt any and all help would greatly be appreciated.

Hello again,

Thanks for the E-mail, glad to hear you are reading old posts. 
Most plants do well in the 80's.  Lower is better than high 80's but not by much.  You need to worry about heat stressing your plants when you get in the 90's and you will have problems with most plants above 100F.  Make sure you take the reading at the top of the plants, LED's do not give off as much heat as an HID, but that will still be your maximum temperatures. The humidity is most likely not going to be a problem for your plants however; you may have problems with mold if you have high humidity.  Ventilation can help with this.  A lot of people have problems with fungus when their plants start to flower or fruit develops so if you can get it down to 50% now, you will have fewer problems later.

You did not mention what medium you use, but watering the plants less can also lower humidity.  Plants need to take water from the soil and push it into the air (called transpiration) but if the medium is also evaporating water you will have higher humidity.  If you are using soil, make sure the top dries out before you water again.  You may need to experiment to find the best medium moisture for your plants with the lowest humidity.

Click here to read a post I wrote on high humidity

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

E-mail Best Way to Improve Flowering in Plants?

Hey Doc,

  What is the best way to improve flowering in plants?

Well the first thing you want to consider is genetics.  You should look for (or try to breed for) plants that have the type of flowers you want.  You can only improve growing so much with the environment; the other 50% is genetics.  Red and yellow light tends to promote and enhance flowering in most plants.  This is why HPS and LED are so often used for flowering.  Also, you want to improve the amount of phosphorus you are giving your plants during flowering.  Nitrogen promotes vegetative growth so you want to limit how much you give plants.  HOWEVER, nitrogen is used to make DNA, and proteins in plants, so I do not recommend not giving your plants any nitrogen, just use a fertilizer that has a lower ratio of nitrogen to phosphorus and potassium.  You also want to keep temperatures and humidity at optimal levels for your plant from start to finish.  The less stress your plants have, the better they will grow.

Read my post on how to get the most from your nutrients

 

Good Growing,

Dr. E.R. Myers

 

E-mail - Out Gassing and Grow Tents

What can you tell me about out gassing? I've read a lot of comments about outgassing killing off plants that were raised in the AgroMax tents that ya'll sell. can you explain/
Thanks,

On Sun, Jun 16, 2013 at 4:59 PM, <askthedoctor@htgsupply.com> wrote:

Hi,
  Just following up, can you give me more detail, or links to sites  that talk about this out gassing?  I have not heard of this.  I would be more than happy to help if you send me some more info. 

I saw a post online where I was researching info on Grow Tents. Several people had posted about their plants dying which they thought was caused by the material that the Grow Tents were made of. I even emailed one of the company's that they had named (HTGSupply.com) to ask what they could tell me about "offgassing". They said that they had only heard of one Company that had this problem and it was "HydroHut". They also mentioned that this was several years ago and since then from what they knew; HydroHut had changed their material for their tents and had no further problems. They also informed me that when they spoke with clients who had complained about their product "offgassing" they came to the conclusion that they were keeping the temperatures extremely high(100 +) in their tents, therefore causing their plants to turn yellow and die. They assured me that their tents are safe and that if used properly with the correct temperature and ventilation there would be no problems with whatever plants I would want to grow.

Thanks again,

 I usually E-mail Perry at Sales@HTGSupply.com with equipment questions.  He said about 6-7 years ago, one company, started offering grow tents very similar to ones HTGSupply.com had at the time.  These tents were white lined tents, not the silver that is now most common.  Apparently the white poly they used reacted to light, and would emit a toxic gas that apparently kills plants.  So, many people thought this meant that EVERY grow tent made did this, regardless of who made it.

Now HTGSupply.com has the Silver lined tents. This is literally a layer of aluminum over the poly backing.  They have tested the tents.  Basically they set the tent up, with a 1000w light in it and ran it 24/7 for a week of two.  They have not been able to get those tents to off-gas at all! 

Now HTGSupply.com does still get off gas complaints.  They send out at least 50 tents per week.  Per month though we get 1 maybe 2 people claiming the tent the got is out gassing because their plants are dead or dying.  When asked how hot is it in your tent, some people say "I don't know but pretty hot" , or "I do not have a thermostat in it but real hot", or, "I do not have any ventilation in my tent and the thermostat is reading over 100 degrees F”.  If you do not have a thermometer, you need to get one asap, growing in a small space or grow tent without a thermometer, or ventilation is not good growing.

So, it seems this is an old problem that comes up now and again, but HTGSupply.com does not sell the white lined grow tents, and has done testing on the tents they do use.

Thanks for your E-mails’ I hope this was informative,

Good Growing

Dr. E.R. Myers

E-mail - Flying Insects in Growroom

Doc,
  I have little fruit flies in my garden.  I am using a soil mixture in 3 gallon pots.  I read on your blog about putting sand on top of the soil and I tried putting sand on top of my pots, but it has not gotten rid of them.  I am going to eat my plants so I don’t want to use any chemicals.  What can I do to get rid of these little bugs?

Thanks for the E-mail.  I think you have what I call soil gnats or fungus gnats.  The adults are harmless; they don’t sting or bite you or your plants.  The larvae (like when a caterpillar turns into a butterfly) eat organic matter in the soil and can eat root hairs which would harm the plants and slow growth.  A test to see if your soil is infested with soil gnat larvae is to look very closely (use a magnifying lens if you have one) you will see tiny little white ‘worms’ or larvae.  Another test is to put a piece of raw potato on top of your soil.  In  just one day you should see little black headed larvae under or even on the potato chowing down.  Since you put sand on top of the soil (perlite or any substance free of organic matter and that dries out will work) you might not be able to do this.  The adults live a week or so, so you will still see them flying for that long.  If it has been over a week, or you see MORE adults you still have a problem.  What might happen is that the soil gnats could be laying eggs using the drainage holes.  Pick up the pots.  You should notice some soil gnats flying from ON the plant, but what you want to look for is soil gnats UNDER the pots.  If you see a bunch of gnats under your pots, this is why putting sand on top did not work, they just found another place to lay their eggs in your grow area.  

You should clean out your trays of any plant matter.  You can then fill the trays ½ full with a 1-4 ratio of hydrogen peroxide to water.  One part 3% hydrogen peroxide, and four parts tap water.  This will work better if the plant/soil is dry.  Make sure the mixture covers the drainage holes for a few minutes.  The mixture should kill most of the larvae but won’t harm your plants if you make the 1-4 ratio correctly and only let the plants sit in the solution a few minutes.

Last, you should get some yellow stickytraps from HTGSupply.com to monitor the soil gnat population.  If you could harvest all your plants at once and clean up everything with the hydrogen peroxide (or bleach for the pots and trays) you should try to wait a week to make sure all the adults in your house are dead.  If you have house plants, you may want to treat them with an insecticide otherwise soil gnats in your house plants will find their way to your indoor garden again.

Let me know if this works

Good Growing,

Dr. E.R. Myers

Click here for other options including insecticides to deal with indoor pests.

E-mail - HPS and Cooling a Grow Tent

Do you have to put a duct and fan to cool a 400w hps light in a grow tent

Sent from my iPad

That depends on the size of the grow tent. If you looked at my posts I have a 3 foot by 4 foot tent and that would need to be cooled (duct and fan), a larger tent might not. Do you already have the HPS?

I am using a 300 W LED and it is giving me better growth than the 400 HPS (less stretching of the plants) and it keeps the grow tent at a nice 82-88 degrees with no duct/cooling, whereas the HPS I used to use would have temperatures in the upper 90's and into the 100's with no ducting, which is going to stress out the plants.
Read my post comparing HPS and LED's
If you have questions about ducting etc. you can E-mail Perry at sales@htgsupply.com, he knows a lot more about the equipment use and set up than I do.

Good growing,
Dr. E.R. Myers

E-mail – Starter Plug Use and Storage

Hello
I’m new to indoor seed starting. I just purchased an AgroMax 55 site seed started kit. I’ll probably only start about 30 seeds.
Should I remove the unused plugs from the foam insert and store them for next year? Or should I just leave them in the tray?

I would remove the plugs and store them in a zip lock bag. If they get wet and are out in the environment, they can get algae or fungus on them. If they dry out, just soak them in water for an hour to rehydrate them.
I really like the ease of use and lack of mess with the starter plugs, I hope you do too. Let me know if you have any other questions,

Good Growing,
Dr. E.R. Myers

E-mail – Wrinkled LEAVES

Doc,
I just started 20 or so seedlings. They are two weeks old with one set of leaves The leaves are wrinkled and the plants are not growing. I am using a T-5HO and I have it about 2 inches above the plants and its been on 24/7. I watered the plants with tap water, then during the second week I used a high phosphorus fertilizer with lower N and K. Please help.

Hello. You did not say what medium you are growing in. If you are using new soil, then most likely it is not a deficiency. Also, you should use a 25-50% diluted fertilizer for seedlings. But since you said you first used tap water, I doubt you already have a nutrient overload. I think maybe you have the light too close. The HO stands for high output, believe it or not, plants can get too much light. Good growers know that most things in Biology involve the Goldilocks principal, not too much, not too little, but just the right amount is what you need. (Click here to read my post on the right height for your light). You should try to raise the light to about 6-8 inches above the tops of the plants. You should notice growing. Growers using LED should also beware of having too much light.
One thing you could try to quickly see if it is overload (stress) from light is turn off the light for six hours. If you raise the light and put the plants on 18/6 for a couple days you should see growth. You can then switch back to 24/7 for as long as you usually do in your grow cycle. If this does not help, send me another 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!
Perry
www.htgsupply.com

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

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

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

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

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
No.

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

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

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

Doc,


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