Why won't my veggies grow?

Asked June 29, 2014, 2:48 PM EDT

I have had a vegetable garden in the same area for about 15 years. The last few years, growth has been pathetic. Peppers stay alive but the plants don't really grow, then they set tiny little peppers. Tomato growth is anemic. I don't use fertilizer, only homemade compost. I usually rotate plantings and plant beans, zucchini, herbs, cabbage, cucumbers, onions, garlic, etc. I have mulch paths (hardwood or cedar) throughout the garden; about every 3 years I use the old mulch from the paths as a mulch for the veggies, and then get new mulch for the paths. As an experiment I built a cedar raised bed, filled it with store bought compost, put it in a different part of the yard, and planted tomatoes. They are growing very well, between 2-3 feet tall, full and green. I would like to do a soil test, but it appears those are really for nutrient deficiencies, and I have a feeling my issue is more like a disease. What type of soil test should I do?

Oakland County Michigan

1 Response

You need to get a soil test for nutrients. Compost is not fertilizer. All the nutrients in compost combined don't add up to 1%. You are using nutrients faster than you are adding. If you used 12-12-12 (for example), you have 23% more nutrients than the compost added. Compost is invaluable for organic matter but not as a fertilizer substitute. The same goes for the decayed wood from the paths.

You can buy a soil test online at www.msusoiltest.com and follow the link to the MSU Bookstore. The soil test self-mailer ($25) will give you this information: soil pH, percentage of organic matter, level of phosphorus, potassium, magnesium and calcium and soil type. You will get a recommendation to correct the deficiencies. There are no soil tests for diseases.

Diseases do not affect every plant at the same time. Diseases are specific to certain plants. This is much more likely nutrient deficiencies than disease. With diseases, you have spotted or dying leaves, marked stems or something that is abnormal that you can see.

Check to make sure that your original garden site receives eight or more hours of full, uninterrupted sun. This could contribute to poor crops. But if you have had 15 years of growing vegetables and putting little back, this could deplete the soil of nutrients. Also check to see if all the old mulch mixed into the soil is giving you multiple lumps for roots to grow around. The wood could be providing many root obstructions. You will know when you dig down to about six inches and see what turns up.

If you are an organic gardener, locate a business in your county that sells organic fertilizers like a nitrogen, phosphorus and potassium source. When your soil test comes back, you will have a location to buy what's needed. It is possible that the soil pH might need to be adjusted. Your ideal soil pH for a vegetable garden is 6.5.

If you get your test results back and need assistance in figuring it out, please contact me...Gretchen...517/546-3950 or voyle@msu.edu