We planted okra in four large containers this year. Three containers had been planted with Crackerjack marigolds - the other celosia. The okra in the marigold treated containers have been producing like crazy. The okra in the celosia container barely grew or produced. I just pulled the okra in the celosia pot this morning. The root knot damage was severe. We don't plant okra in the garden. it is too much of a nematode factory.

I have had to deal with RKN several times, this year was my worst. I planted Florida Broad Leaf Mustard where the damage was the worst. I also added a yd. of compost. It seems as though tilling in the mustard in the spring helps. I have also used grain rye cover crops that seem to help. I also try to winter till if I don't have anything planted in the area. I have also used Vapam years ago. I don't think that I can safely kill out RKN without damaging my soil, I just try to manage their population. I am sure they sometimes reduce my production, but they have never shut me down.

I can't say for certain but slowpoke might be right about winter tilling. Also I understand you can kill the nematodes by sterilizing the soil by stretching plastic sheets over it if you plant in beds. The heat from the sun under the plastic kills the nematodes.
Okiedawn can probably tell you better than I can.

This post was edited by Auther on Tue, Oct 7, 14 at 21:45

Root knot nematodes are so frustrating. They tend to build up big populations in sandy soil and sandy loam soil that are low in organic matter.

There are many things you can do, and some of them may seem effective and others may not. What works for one person in one situation doesn't always work for another.

My favorite solution is the planting of Elbon rye, which was developed right here in Oklahoma by the Ardmore-based Samuel Roberts Noble Foundation, in conjunction with then-Oklahoma A&M University, I think, long ago. I believe Elbon was released in the 1950s but they had worked on it for a long time. (Elbon is Noble spelled backwards.) You can buy Elbon rye at feed-and-seed type stores and sow it in the fall, grow it over the winter, and plow or rototill it under in the spring, planting a couple of weeks later.

The way that marigolds work for nematode-control is that they trap the nematodes in their roots where they then die, so the best way to use nematodes is to plant them thick like grass one year, and then plant nematode-susceptible plants in that bed the next year.

Oldokie, What sort of plants are you seeing the RKN damage on? If it is tomatoes, for example, then one way to try to work around it is to plant only varieties that have some tolerance of nematodes bred into them.

You can solarize a bed like Auther says, although it works best if done for a month or two of hot weather. I don't know how effective it would be if the solarization is being done in fall/winter.

Adding organic matter to your soil is said to help, but sometimes when a heavy infestation already exists, it doesn't seem to help as much as it does in a virgin garden area that has just been rototilled, amended well and then planted.

If the nematodes are a problem in only one part of the garden, a standard method to reduce the problem is to rotate susceptible plants to a new part of the garden every year for 3-4 years. This prevents them from building up heavily in one specific area. Unfortunately, it may mean you have them everywhere in the garden after 3 or 4 years, but at a lighter infestation than if you grow nematode-susceptible plants in the same place year in and year out.

Because nematodes are susceptible to cold (that's why northerners don't have trouble with them in their colder climate and we southerners obviously do have lots of trouble with them), rototilling deeply in winter couldn't hurt and might help.

Some people have found success from adding chitin to their soil, but that works better for folks who live near an ocean and have a ready source of chitin available. I doubt it would be cost-effective to have a significant amount of chitin shipped to Oklahoma.

I hope you are able to find a solution that works for you.

I've linked info about solarization from the Noble Foundation.

Dawn

Here is a link that might be useful: Soil Solarization

I thought I might add that where I live is very sandy soil and sometimes the nematodes are every where and I can pull up different kinds of weeds in my fence row and they will have nematodes root knots as bad as my okra or other garden vegetables. But the weeds seem to not be bothered by the knots like vegetables are. Vegetables will sometimes be stunted or die all together. But in places they will be so bad on one plant and plants on either side will not have any sign of nematodes at all.
You might check out - Control of plant-parasitic nematodes with organic & inorganic amendments in agricultural soil.
Maybe it can help.

the plants that showed the most damage was okra, some varieties of tomatoes and green beans. went to county ext. and he told me the only thing to do was move my garden

This post was edited by oldokie on Thu, Oct 9, 14 at 14:39

I've been reading "Teaming with nutrients" by Jeff Lowenfels. There are certain fungi among a billion life forms in a teaspoon of soil that will help fight off nematodes. Nematodes are always present. When the evil ones are in abundance, something is out of balance. You might need change a few things like growing Rye over winter or altering a few gardening methods or you might need to change everything, but limiting nematode activity is possible with some soil-buddy help.

I highly recommend this book as well as his previous "Teaming with Microbes". His second book can be read without having read the first. He goes into deeper detail. But prepare to study this shelf book. It's a jewel.

bon