Dr. Grow: Preparing the soil so plants thrive instead of survive

In my last column I discussed the steps needed to establish a new vegetable garden in an area that has not been used before. The activities included mixing organic matter, gypsum and possibly lime or sulfur into the soil to create the proper soil structure and pH.

Today I want to discuss what you need to do to make sure your garden soil has the correct nutrient levels to support plants that thrive instead of just survive. Most soils in Southeast Missouri have sufficient phosphorous and potassium to support plant growth, but just to make sure, collect soil samples and run a soil test on them.

To collect samples, use a spade or a trowel and collect about a cup of soil in two or three places in your garden. Be sure to go down about six inches when collecting the samples. Most roots of vegetable plants will remain in the top six inches.

Mix the soil samples together and take them to your local university Extension office. They will test the samples for a small fee. If you are a do-it-yourselfer, purchase a soil test kit at your local garden center. Run the samples and then make any additions to the soil that the test kit or the Extension office recommends.

If you have trouble interpreting the test results, take the results to your local garden center and ask a clerk for help. You may find that you need to make some additions of phosphates or potash to bring the soil to adequate levels.

Once you get the soil nutrients to the proper level, it is time to plant, assuming the season is right. If you are planting cole crops, lettuce, okra, tomatoes, etc., always water them after planting with a high phosphorus fertilizer such as a 9-59-8. You want to tell your newly planted vegetables to spend their energy in root formation to start with. This fertilizer will give them that signal.

Once vegetable plants are established, you should then fertilize the growing plants with an unbalanced fertilizer such as 11-15-11 with micronutrients. Be sure that the middle number, phosphorus, is higher than the first number, nitrogen. At this stage of growth, the fertilizer balance will tell the growing plants to produce more roots and also flowers and fruits.

The addition of micronutrients will eliminate some occasional deficiencies that show up in soils in Southeast Missouri. The micronutrients are needed for efficient chemical reactions in the growing plants.

I have suggested an unbalanced fertilizer because I have heard the following complaint too often. "I used 12-12-12 in my garden and all I get is plant but no fruit and no root crop. What's wrong?" A gardener can influence how a plant grows by the balance of nutrients applied to the soil. If the nutrients are balanced, the plant makes the decision on whether to grow roots, fruits or flowers. If the gardener uses an unbalanced fertilizer, then the decision on whether to grow roots, fruits or flowers is in the hand of the gardener.

With good soil and fertilization, you should enjoy the fresh, flavorful and healthy benefits of your vegetable garden. Enjoy.

Send your gardening and landscape questions to Paul Schnare at P.O. Box 699, Cape Girardeau, Mo. 63702-0699 or by e-mail to news@semissourian.com.