E- mail -- basic soil, nutrients,water/feeding schedule

Hi Dr. Myers
One of the most confusing parts (for me) is nutrients, soil and watering.

I'm not a gardening person, I'm not green thumbed so all this fertilizer numbers, ph and moisture is baffling to me. Could you please explain to me in plain terms what basic soil, nutrients, water/feeding schedule I would need?

Thanks for your E-mail.
You are right there is a lot of information to know to be a good grower. The good news is that if you just know a few basics you can be successful, and then build on your success as your knowledge grows.

I wrote a previous paper on nutrients LINK
And on how to water properly LINK
And a previous post on soil LINK
And on what containers are best to use LINK

There is a lot of information in these articles and links to others, so I will try to break things down in simple terms for you here. If any of the more advanced growers can think of easier ways to explain things please leave a comment for me.

Start with a good potting soil. You don’t need to worry about pH or even much about nutrients with a good soil. I always tell people, "Don’t even think about hydroponics or soil-less mediums until you master growing in dirt".

Start you plants in small containers and put them in bigger containers as they grow. Most plants need a minimum of ½ gallon of soil for every foot of growth. Simply put bigger containers are better than smaller but see my container article for more information
It is vital that all containers have a drainage hole. When you water it should come out the bottom of the container so that you know the soil is saturated completely. Watering is important, but usually is done too much. When growing in dirt, you should never water a plant if the top layer of soil is still moist. Containers dry from the top down so if the top is wet the whole container is too. Pick up the plants every time you water. The weight will tell you how much water is needed. Heavy pots need less, light pots are dry and need more.

There is a ton of information on nutrients.  The most basic thing you need to know is that the three numbers on any fertilizer are always describing three nutrients in the same order.  FIRST is always the percentage of nitrogen SECOND is the percentage of phosphorus and THIRD is the percentage of potassium. These (NPK) are the most important nutrients that plants need in large quantities. A general fertilizer with all three numbes the same like 10-10-10 is all you really need if you are growing in potting soil. I like fox farm products but use many others too.
  If you want to try a couple different fertilizers, instead of just a 10-10-10, many growers start off by giving young growing plants a fertilizer with the largest number the first 6-4-4 (NITROGEN). Nitrogen helps plants grow vegetatively. Then some growers switch to a fertilizer that has the highest number the second PHOSPHORUS like 2-8-4. Phosphorus helps plants make flowers and fruits. If you are growing in potting soil you don’t need to worry too much about micronutrients. Compost is one way to make sure you have micronutrients, but there are many fertilizers you can buy as well.

I hope this helps you get going. Let me know if you run into any other problems.

Good Growing,
Dr. E. R. Myers


Winter Solstice Gift For You

Happy winter solstice!
Since this is a time of year most people give gifts, I will give you something. Surprise! It is advice. (Lame I know but read on) I advise you to give yourself a new bulb. This is a great idea for a number of reasons: First, older bulbs put out less light which will slow down plant growth and/or reduce yield. Second, it is a good idea to have a back up incase your current bulb breaks. If you do not have supplemental light and you break a 400, 600 or 1000 watt bulb you may not be able to get a replacement the same day. It may take several days if you need to mail order. You don’t drive a car without a spare tire do you??? Have a back up bulb! If you order a new bulb you can keep the current one as a backup. An old bulb putting out 50% light is better than messing up the light cycle and stressing out the plants (and yourself) waiting for a new bulb to arrive. Did you know that a MH can loose 30-50% of its intensity in the first year? An HPS is much more durable loosing 10-20% over a couple years, but all bulbs loose intensity the more they are used.

On an environmental note, HID bulbs can have mercury or other heavy metals in them, as can florescent, so you should dispose of them properly. An internet search should help you find the nearest recycle center.

Happy Winter Solstice
Dr. E. R. Myers


Speed up Growth Cycle via Light Intensity

As you know, photosynthesis drives plant growth. An easy way to speed up a plants growth cycle is to give it a greater light intensity. The cheapest and maybe simplest way to grow is with T-12 bubs from a hardware store, and many growers including my self started out that way, but they don’t compare with a T-5. If you want big plants or plants for fruit or flower, you will need to use an HID like an MH or my favorite, an HPS. While plants don’t use light the same way we ‘see’ light, lumens are still an ok way to look at light output. The more lumens a bulb has the greater the light intensity. The color of light is also important. An HPS has a superior light output vs. an equal wattage MH, but its yellow light output makes some plants grow lanky. I recommend using a fan and/or tying plants down. You can also use a MH conversion bulb with a HPS ballast for vegetative and then switch to the normal HPS bulb for flowering/fruit. In some cases, these conversion MH bulbs put out more lumens than an actual MH!

I think the fasted way to get plants to maturity is to start them under a T-5 (blue bulbs) in small containers and then pot them up and put them under a HPS when they are big enough to flower. I have a conversion bulb which I use for a couple weeks and then switch to a high output HPS bulb. I usually put a fan blowing on the plants very briskly for the first couple weeks when I switch to the HPS to help counter act the internode stretching that sometimes occurs between plant nodes when plants are grown under HPS. Once most plants have begun to really flower you can cut the fan back to low because plants stop stretching when they have prodcued the hormones for flowering which leads to fruit or seeds.


I started several pumpkin seeds from the same hybrid on a wet paper towel in a plastic bag. The seeds that germinated I put into plastic cups and grew them under a T-12 light for two weeks. All were sitting on a root warmer. After three weeks I potted up eight plants, four I put on a window in my office (winter short days) and the others I put on a shelf with a 400 W HPS with a timer -- on 12 off 12 (mimic short days).  Every day was "sunny"for the HPS, but the window had at best several sunny days and only 1 hour maximum of direct sun on those days.  I apologize that the pictures did not turn out that well but at least you can see that the plants under the HPS are bigger and are flowering. The window plants had the same number of hours of light  but are basically stagnant or growing slowly.  Even the HPS plants are not the best looking plants because they are in small containers.  I kept all plants in the same size pots so that everything would be the same accept the light intensity. I should have transplanted the bigger plants under the HPS into 5 gallon buckets if I really wanted to harvest them.

Good Growing,
Dr. E. R. Myers


Speeding up grow cycle via Breeding

In my previous post about starting a breeding program I mentioned that you should always be ruthless in the plants you select of your breeding program. Don't get mired in meritocracy.  I also said that you should observe your plants through all stages of growth as you make your selection for which plant(s) will be the parent(s) of your breeding line.
Another way to speed up the growth cycle is with your breeding program.  Most people pick the biggest, best tasting crops to put in a breeding program, consider looking at the rate of germination and time until flowering as traits to select for.  Remeber that faster flowering does not always mean increased or good yields.  Decide what is most important for you.

There is some genetic determination in how long it takes a seed to germinate.  What this means is that if you pick the first seeds that germinate as a trait as you breed you will see shorter and shorter germination times. You can speed up  the growth cycle by breeding for other traits: the fastest growing plants, the first to flower, or finish flowering or to produce seeds will have a genetic factor (genes) that gives them this trait.
One characteristic I personally have chosen in a breeding program is early flowering. For several generations I picked the first plants to flower as the pollen donor and recipient as the primary trait I was breeding for. I did this because I wanted my plants to flower before the end of the semester. After a few semesters I had many plants that would be done flowering two weeks before the end of a 16 week semester! The problem was these fast flowering plants were shorter, had smaller flowers and were not as nice as other flowers that took longer to flower. The lesson here is that while choosing plants that flower early will speed up the growth cycle, you may sacrifice other traits like color, smell or even yield. When you are breeding make sure you choose the most important traits to you, but keep in mind things like time to flower, size etc. I have crossed a big beautiful flower with an early flower in order to have big flowers that finish early. I hope to let you know of my success.

Good Breeding,

Dr. E.R. Myers


How to Speed up the Growth Cycle

– The growth cycle as I use it in the next few posts means the time it takes to go from seed to fruit/flower. There are other factors to consider besides time until harvest. Size is the first to come to mind, small plants in general will be ready to harvest before big ones. Many indoor growers have limited space and therefore grow smaller plants in smaller containers or simply change the light cycle to induce flowering/fruit sooner. Yield is also an important agricultural trait to consider. Plants that are smaller tend to be harvested earlier and tend to have lower yields. If you let your plants grow for longer/get bigger in most cases you get greater yields. In many cases my goal is to maximize all factors without harming others, you need to decide if one factor is more important than others and grow your plants in a way that is best for you. Please see my other articles on limiting factors (link) if you want more information to help you speed up and improve your grow cycle.

If you already have plants, see my post on vegetative growth and speeding up the growth cycle.  If and when you are starting new seeds please read below.

Speed up the growth cycle Seeds – Shorter seed germination is the first and one of the best ways you can get a real jump on speeding up the growth cycle! Depending on the variety of plant, Warmer temperatures can take 3-7 DAYS off the growth cycle. I use a heat mat.  I like to start seeds using the starter plugs  and I put the whole seed tray on the heating mat. I also have used hot houses with a plastic cover to keep humidity high and sometimes I use a heat mat with small pots when I start seeds in soil mixtures. Keep in mind if the pots are too big the heat won’t get to the seeds. For example, 16 oz. plastic cups are a bit too big to get the heat to the seeds in the top layer of soil in the cup. I have also put seeds on a wet paper towel in a plastic bag on top of a heat mat which also speeds up germination.

YOU SHOULD KNOW, I did an experiment to test the effect of using a heat mat on growing Coleus. As expected, the seeds germinated on the heating mat emerged 2-5 days earlier and the seedlings were bigger for the first week. THEN, the plants without a heating mat caught up, and passed the heated plants. The non-heated plants remained bigger until I potted them all up and moved them to the display area. I suggest you do a similar experiment: If you have room under your light for seedlings try placing some plants on a heat mat and others not on it. My first thought was that the Coleus did not like the heat mat once they were established. When I looked at notes and pictures I realized that the plants on the heat mat were watered more often. Two times a week I would spot water the plants meaning I picked up each plant and watered it if it was lite but did not water it if it was heavy. The heating mat made the plants dry out faster and after each weekend I noticed the plants with the heat mat were always dry (never wilted though). So, it might have been low soil moisture and not temperature the caused the slower growth rate. The lesson learned is that if you do keep soil warmer with a heat mat make sure you keep the soil moist, but obviously not soaking wet (watering link).

Good Growing
Dr. E.R. Myers

Notice the plants on the right (that did NOT have the root warmer) are taller, even touching the light athough I have the light on an angle to make it higher for the non-warmed plants.  You can see the heat mat under the plants on the left.


Containers - Know which is best for your plants

A while back I wrote about containers and suggested some minimum container sizes for plants that are good to grow indoors – Containers LINK. I would like to build on that and lead into the topic of how to set up a grow room which I will be talking about soon.  Most indoor growers will use several sizes of containers. Typically, plants are germinated or placed into small containers after germination and then transplanted to progressively larger containers until flowering. Starting many plants in small containers allows the grower to pick the best plants and get rid of the weak ones. Good growers cull inferior plants at each transplant. Starting many plants also allows growers to look for traits and attempt to incorporate these traits into a breeding program.

Seeds can be germinated in starter plugs and grown for 1- 3 weeks. If you are not growing in new potting soil, you should add nutrients. Young plants need all nutrients (N-P-K and micronutrients) but for seedlings, like cuttings you should give them a fertilizer with a high phosphorus percentage to promote root growth. No matter what nutrient regime you use, your plant growth will be inhibited if you do not transplant them into a larger container. I like the starter plugs because like rockwool they are easy to move and I think really minimizes any transplant shock. If I don’t use a starter plug I like to start seeds on paper towels and put a seed in a plastic cup with a potting soil mix. I like plastic cups because they are cheap, easy to get and are light and easy to move around. A six ounce cup will hold a plant for 1-2 weeks maximum. I use the 16 or 20 oz. cups for 3-4 weeks respectively. A half gallon container  is good for plants for upto six weeks. For minimum sizes for different plants please see my previous container post .  A good rule of thumb I have heard is that you should give a plant ½ gallon of medium to support 1-2 feet of growth. This rule depends on your use of fertilizer and proper watering. Obviously, plant growth habits differ so if you have a plant that has branching you should grow your plants in larger containers. As you can see in the picture at the bottom of this post, plants grown in containers that are too small are stunted and I can tell you will have lower yields.

While transplanting or ‘potting up’ is important to save space and enable a grower to pick the best plants from many, plants do better if they are NOT transplanted often. You can count on losing 3-4 days of growth after each transplant. However, if you are growing many different plant types, have multiple grow areas, or move your plants around you will need to do some transplanting to be a good grower.

As I have mentioned, my favorite containers are plastic pots. Plastic pots are inert, reusable, lightweight and convenient to use. Metal containers may react with the medium, nutrients or plants. Plastic bags are also convenient with their square bottoms. Fiber containers are also popular and I have used many types myself. They are not too expensive, can be used for more than one growing cycle and are easy to dispose of in a compost pile or in an outdoor garden as organic matter.
I will end with one last piece of advice concerning containers…. When you are transplanting into larger containers, some growers put sand or gravel at the bottom to increase drainage but also to balance the plants so that they do not easily tip over.

Good Growing,
Dr. E.R. Myers

In the picture below, notice the two white meter sticks between the plants.   I have planted 1, 2 and 3 corn plants in identical sized small plastic containers. I assume this means that the plant have 100% 50% and 33% of growth medium from left to right. You can see the size difference with your own eyes. For this little experiment, all plants germinated the exact same day, were grown under the same 600 watt HPS and given the same fertilizer regime. These plants are also a hybrid from the same batch so they are genetically the same. The only difference is due to the lack of container space for the roots. Notice too that the single plant on the left is a darker green. This is a sign of plant health and vigor. I have noticed that plants that are in larger containers and growing rapidly have a greater disease resistance than plants that are stunted in small containers. You may hear people tell you that you can grow plants in small containers if you provide all the right nutrients and water but if you have small containers and your plants roots are not growing this means that overall above ground growth and yield will be lower. Growing roots send out hormones telling the plant that things are ok and that is should continue to grow. If a root is blocked inside a small container it will tell the rest of the plant (via hormones or other molecular signals) not to grow since water and nutrient uptake may be limited.