Thanks for Lisa for the cone flowers. While enjoyable, their growth has been the primary indicator that something's not working for other plants.

Further reading suggests vermicompost is more beneficial at suppressing nematodes (and spiders, etc.) than any other soil amendment or compost if aerated and applied immediately after brewing.

According to Clive A. Edwards, Norman Q. Arancon, Eric Emerson, and Ryan Pulliam at:

Soil Ecology Laboratory
The Ohio State University
Columbus, OH

testing revealed a solution of aerated worm compost teas were effective at greater disease suppression, nematode suppression and reduction of spider mites and other pests.

The ratio of solid vermicompost to water suggested is: 1:5 (20%), 1:10 (10%) and 1:20 (5%).

Most importantly, the "tea" must be aerated.

I use two fish tank bubblers per 5 gallon tea because it "bubbles" showing microbial actions.

It looks like I need to continually feed the soil vermicompost tea - especially during peak nematode season (temperatures greater than 64 degrees).

The addition of marigolds throughout the garden would increase the effectiveness.

Any suggestions are certainly welcome, but it looks like I have what I may need.
____________________________________
Source:

(2007, Edwards) .pdf at http://www.growingsolutions.com/home/gs2/page_222

I'd be remiss if I did not revert back to what okiedawn always suggests: Giving the plant what it needs to fight off whatever is attempting to destroy it.

Bon, If you plant Elbon rye, which is a cereal grain and not the same thing as perennial or annual rye grass, it will help you a lot with the nematodes, if nematodes are even the issue. Elbon rye was developed by Oklahoma's Ardmore-based Noble Foundation, and one "secret" about Elbon rye is that its name is Noble spelled backwards.

You plant Elbon rye in the fall.

The hard part about using predatory mites is that they work best at certain temperatures, so that limits their usefulness here because we often are too hot for them to be viable for long.

In order for marigolds to work for control of the nematodes, you'd have to plant the marigolds as thick as grass, and all marigolds are not useful for nematodes---only a specific variety really is effective at all.

Root knot nematodes tend to get out of hand in soils that are very low in organic matter. That is one reason they become so much more of a problem in soils with a high sand content than in soils with a high clay content.

Remember that if your plants' problem is RKNs, then when you pull up dead plants, the roots will have lots of galls, often referred to as knots, in them. If the roots are not covered with knots or galls, then the issue is something else and not RKNs. Adding chitin to the soil helps, but since we are not near the ocean, you'd likely have to have chitin shipped and I think that makes it cost-prohibitive for people who don't live near the coast where it is more readily obtained.

I'm more inclined to think there is some sort of mineral deficiency in your soil than nematodes since you never see knots on your plant roots. It is hard to diagnose mineral deficiencies just by looking at how plants perform, and that is especially true with micronutrients (trace elements) as opposed to macronutrients (N, P, K). The issues you are seeing likely are a nutritional issue, and they are worse in summer due to the stress caused by summertime temperatures and the intense sunlight to which are plants are exposed in the summer months.

While it is relatively easy to add the macronutrients (N, P, K) to the soil, it is trickier to try to increase the micronutrients. There are some micronutrient fertilizers available, but there's an even easier way. Years and years ago, Howard Garrett (The Dirt Doctor) wrote that if you use decomposed tree leaves to improve your soil, they will not only contain all the nutrients the soil needs, but they have them in the right proportions. Since then, using grass clippings and autumn leaves as soil amendments is about all I do to improve the soil, along with adding homemade compost. We have beautiful, healthy soil in the areas that I've amended. The amending never ends though because heat eats compost.

Because you seem to see the issues with the plants worsen in the hot, summer months, I think I sort of have a news flash for you---what you are seeing is caused by the heat. There is a huge difference in the way plants grow and produce in milder months like May and June than in July and August. In the rare years that we have a cooler than average summer, I'm always astonished at how much better the plants perform. Plants that are amazingly beautiful and productive at 85 degrees can quickly turn miserable at temperatures of, let's say, 95 and above.

If you've never had a soil test done, you can get one done through OSU for about $10.00. That's a good starting point in terms of seeing if your soil is too high or too low in any of the nutrients they measure with the soil test. Soil that is too high in some nutrients can be as bad as soil that is too low because the high levels of some nutrients can interfere in the plants' ability to take up and use some other nutrients. They not only can do the basic test for $10.00, but if you're willing to pay a few dollars more than will test your soil for secondary nutrients and micronutrients. Without a soil test, you really don't know if the problems with the plants occurs because of the soil or if what you're seeing is just the usual stresses of summertime. In order to 'fix' the soil, you first have to determine what is wrong with it.

It also could be that your soil has plenty of the nutrients needed, but that it has either a very high or very low pH that needs to be corrected. A soil test would tell you your soil pH.
Dawn

Here is a link that might be useful: OSU Soil Lab

I lost my okra again this year. It started losing leaves about 3 weeks ago after we watered it well. When we dug up a couple plants, they did have the typical knotty roots. I wish I would have laid some clear plastic over the area where I plan to have okra next year--it's been empty since the corn came out in early July--when I first noticed the dieback, but I didn't and I am afraid that now it is too cool to effectively solarize. We do amend with rotted leaves and compost but still have a problem, although okra is the only thing that actually dies.

I keep reading. Good discussion going on over in the soil forum about it, too. But they're not from Oklahoma and you're probably spot on about the heat. Reading further, I see very high temps (and you mentioned it) actually kills nematodes.

Someone brought up the matter of high phosphorous potentially stunting growth in the manner I describe?

(and the fact that i need soil testing)

Someone reminded me too much compost no matter how "good" can be destructive.

(and the fact I need soil testing)

I read about leaf mold (or some type of it with certain leaves) produces the beneficial nematodes. That puts making leaf mold in a new light.

But around here.. this is the first year we'll actually leaves. 3 years.

Bill's working so a soil test is coming. Then, ya'll can put up with me trying to interpret it, running off into no where land jumping the gun about something that's probably not relevant at the moment or about some fancied issue.

mulberry, I am so sorry you're experiencing RKN. I always look forward to updates on these matters, so I can know what works or doesn't.

Part of the reason I'm so determined is that next year's garden isn't for pussy-footing around. We're going to need something on the table.

Thanks for you input! I have learned a tremendous amount on this matter and continue.

I had Rootknot Nematodes a couple of years ago. I thought I may have them again, but I had two plants pulled so I could check the foots. My okra is suffering from cucumber beetles and drought.

When I had the RKN infestation I tried different things, all seemed to help. I liked adding extra compost, winter till, and growing cole crops. The areas that did best was the Florida Broad leafed mustard, because it was still productive for food and the deer did not care for it. The Elbon Rye is great also, but it is hard to till in and is a deer magnet.

Larry

Bon, Do you have sandy soil? Sandy loam? The looseness of those soils combined with low organic matter allows the nematoes to easily move around, and then they seem to multiply like mad. In clay soil, even in the absence of much organic matter, it compacts so tightly they cannot move around. As much as I hate the dense red clay, we did choose it. We almost chose another place when we were looking for land to buy, but it had very sandy soil---like sugar sand---and I was really worried that I'd have a constant nematode issue. The last thing on earth I wanted was to buy a place that had the kind of soil that allows nematodes to multiply and spread.

High phosphorus was indeed on my mind when I suggested a soil test, but you'll never know if it is high phosphorus until you get the soil tested, so we're just guessing that might be part of the problem. It really is impossible to correct problem soil when you don't know what the problem is. Nematode-infested soil is problem soil and, while adding lots of organic matter (and clay if you can get it) will help, it may not correct the soil enough if you have a major nutrient imbalance. Or, if your pH is very high or very low, organic matter will not necessarily be able to correct that on its own either. Generally, if you have the kind of soil that allows nematodes, there's also nutritional deficiencies or something else going on as well because rainfall leaches nutrients out of fast-draining sandy soils very quickly. So, when you have a problem in your soil that manifests itself in poor plant growth, there's normally multiple issues occurring and you kind of have to work your way through correcting them bit by bit. There's normally not just a quick fix.

WIth the band of sandy soil at the west end of our garden, I not only added lots of organic matter to it to deter the nematodes I thought might be there, but I also added clay soil whenever we did some excavation (for example, when they dug out the clay soil to put in the tornado shelter, we were able to move all that excavated clay elsewhere). I've often thought that if I could take a giant mixer and blend together our clay areas with our sandy areas, we'd have great clay loam, although I'd still have to add organic matter every year.

Dorothy, I've solarized in fall and winter using heavyweight (6 mm) clear plastic. It takes a lot longer in fall/winter than in spring/summer because the temperatures are lower and the daylength is shorter, but I did feel like it worked. Or, you could plant Elbon rye there where the okra grew. It is a good cool-season cover crop that helps fight nematodes.

Bon, In our climate you have to try really hard to achieve "too much" compost in your soil. Because "heat eats compost" and makes it break down very quickly, we seldom run into the issue of having too much organic matter in the soil here in our climate, though it can be a more common problem in some milder climates. To get "too much" organic matter in your soil, I think you'd have to add more than 6-8 inches of organic matter all at once, and even then, I think you;d be shocked at how quickly it all breaks down. I have added tons and tons and tons of organic matter to my soil since we moved here and never once have had any sort of problem that could be linked to having too much compost or organic matter in the sol. It breaks down so quickly, in fact, in our insanely hot summer months that some years I look at the soil in the fall and wonder if I'll ever get enough organic matter into it. Organic matter simply breaks down faster than I can add it, long-term.

Larry, I could say that my garden is suffering from drought, but that is not even an accurate-enough description. My life is suffering from drought. : ) Not only are trees defoliating constantly, a few have begun dropping large limbs just like they did in 2011. At the rate we're going, our 10 acres of woodland will vanish in the next 20 years if we keep having drought years back to back to back. On the bright side, there's beautiful soil there in the woodland so maybe someday it will become a garden.

You must have had my cucumber beetles at your place this year because II barely saw any here and usually they are all over everything 24/7. I have some ugly, cucumber mosaic virus-infested Armenian cucumber plants that look pathetic but are still alive and still producing about a dozen very large Armenian cukes per week. I've been feeding them to the deer. I don't think I've ever had spring-planted Armenian cucumber plants survive this late in the season. Usually the cucumber beetles spread the disease around over and over and the plants die.

I like to plant plain old rye grass around the house and other structures for winter fire protection, but it is too dry to do that this year. With moisture levels in the soil being incredibly low, the seed wouldn't even sprout unless I watered every day. The deer are so hungry right now that I think they'd devour the rye grass before it could root in well even if it sprouted. In prior drought years, as soon as the rye grass sprouted in those years, they yanked it out of the ground while eating it. I wasn't a happy camper. I reseeded the big bare patches, and they yanked it out as it sprouted so I gave up on having green winter rye grass around the house that year.

One year I planted a food plot for the deer. It wasn't fenced in and they had free access to it, but they ignored it and ate our shrubs instead. The rabbits did enjoy the deer food plot though. The seed for the food plot was one of those mixes you buy in bags in late summer to plant for a fall and winter deer food plot. and I remember that it had mustard, collards, turnips and clover in it. The rabbits were particularly fond of the clover.

Bon, I'm going to link a page that shows the effects of different mineral deficiencies on tomato plants. You might see something there that resembles what you observed in your tomato plants this summer.

Dawn

Here is a link that might be useful: Color Photos of Mineral Deficiencies inTomatoes

Dawn;
I have clay, mostly. The soil was, primarily, a garden area many moons ago. When we moved it was covered in clover and a few other cover crops I believe she intentionally planted.

The drought knocked out the clover and replaced it with creeping charlie, but the clover is starting to come back with recent rains. I hate when the clover isn't there because the early bees need it.

From 2-4" I have a pretty good top sandy loam. Under it is a dark clay. If it were any worse, it would be that gumbo gunk.

amending it with compost does really well, though it remains pretty heavy.

One of my front planters I used with a dug in hugulkulture beneath is where I sat down with a bucket of clay, a bucket of top soil and a bucket of very old leaf mold from one of the fence lines. I sat there and broke down the clay pieces and mixed in with the other. It is my absolutely best garden soil though I transferred climbing grubs along with it. It's little mini climate is stabilizing.

I don't think I'll ever go to that trouble again, but I'm always happy to pick up the soil by hand with ease and marvel at the results of my hard work.

I can attest mixing the soils together and adding great compost does work, but unrealistic long term.

I should be ordering a soil test next week. As usual, we're coming up short with funds, but I'm going to cut something else out short term to get that done. Only one, for now. I can test other spots later down the line.

I need those tests, without a doubt!