I previously posted about a problem I have in my vegetable garden with root knot. Plants affected by the root knot nematode have roots that look like this:
Notice the little round “knots” growing in the roots. These knots are the damage caused by the nematodes, and reduce the plant’s ability to uptake water and nutrients. The plants wilt easily, rarely bear fruit, and eventually die. Digging up the wilted plant quickly reveals the problem, and indicates another lost harvest.
My fledgling research on the subject revealed more speculation than solutions. Apparently, the type of parasitic nematode in my garden also affects cotton plants. My 60-year-old house resides on former agriculture land, and cotton was a likely crop. Poor agriculture practices from decades past may be affecting my present-day garden. My neighbor does not have a root knot problem, but her house occupies an old citrus orchard and not an old cotton field. I also learned that cotton is related to okra, and that both plants propagate root knot problems. I probably did not help the situation by planting okra every summer. Other contributors to my infestation could be planting things too closely, and a lack of freezing winters as of late.
I have yet to read an easy solution. Apparently, commercial farms sometimes use chemical treatments, but I am hesitant to try such drastic and potentially harmful measures just so I can have a vegetable garden. Using chemicals also defeats a main purpose of growing your own food.
Based upon what I read, here is my attempt at controlling this problem:
First, I cleared off all the plants and weeds from my garden. Next, I laid down a plastic tarp to cover the entire treatment area. I weighted the edges down with bricks and rocks, and left it in place for about two months during the hot days of May and June. Some days the outside temperature was 110-115 degrees Fahrenheit, and the trapped heat under the tarp caused the soil temperature to rise much hire than that. The high temperatures under the tarp should kill the nematodes, as well as weeds, and unfortunately beneficial organisms as well. After two months, the plastic sheet was tired and rotten, so I removed it, turned the ground over, and placed another plastic tarp. This tarp will remain in place until it is time to plant winter crops at the end of September.
I also read that overloading a garden with compost will help control the parasitic nematodes, because the decomposers that break down the organic material compete with the nematodes, keeping their population low. Before I plant again this fall, I will spread about 4 inches of compost atop the whole garden. I will sow my seeds directly into the compost. For future planting seasons, I will probably just spread new compost instead of turning the soil over, and have a no-till garden.
Hopefully, this will work. I will post the results of my efforts this upcoming winter.