A Test to Know if You Grow With Optimal Soil Moisture?

In my previous two posts - Maximizing Root Growth in Containers - I talked about maximizing the area where roots grow (Thereby increasing overall plant growth and yield) by keeping the entire soil moist with mulch and trying different types of soil amendments to keep the moisture at the optimal level.  I have also written a more scientific look at soil and water availability.

I want to reiterate that the most common problem I see with indoor growing is over watering, but just like too much water is bad, too little water is not good growing either. I have on occasion gone away for a week or more. I watered the plants well before I left, and when I got back, they were not wilting but the soil was very dry. I watered the plants and in two days, I could easily see growth.  I  could see the soil and pots through the leaves when I returned, but two days later, the leaves /plants had grown so much that I could no longer see the soil/pots.
What happens when the soil moisture gets low is that little holes in the plants called stomata close to conserve water. The good news is this keeps the plants from wilting or dying for a while. The bad news is that carbon dioxide ENTERS the plants through the stomata. This means that photosynthesis will come to a halt and the plant will basically just sit there, not growing, and not wilting.

HOW TO TEST YOUR SOIL MOISTURE

I have used a soil moisture meter, from HTGSupply.com. However, I lost it when I moved a couple years ago, and I have been using sight and the tip method in my greenhouse. First, get to know the color of your grow medium when it is wet and dry. My soil is a dark almost black color when wet, and brown when dry. Second, when the top is brown (or dry looking), I tip the plants and feel how heavy they are. If the plant is very light, and almost falls over with a little push on the pot, it is very dry and needs a lot of water. If the pot is heavy, I just give the plant a bit of water to darken the soil on top. If your plants do get very dry (easy to tip) You may want to water them two or three times with small quantities of water. Water is cohesive, meaning it sticks to itself. So, if your soil is very dry, the water will run right out. If you water a 1-2 gallon pot and water runs out in a second or two, you have very dry soil. Give it a few light watering's and you should notice the water is staying in the soil/pot.

You want to make sure you soil is wet, so that plants are not water stressed and keep their stomata open, but not too wet (soggy) where plants roots suffocate and plant growth stops and leaves yellow.
Good Growing,
Dr. E.R. Myers