I am planning for an organic garden this spring in Bixby, Oklahoma on my grandmother's land since I am currently living in a condo. However, she claims that nematodes are a recurrent problem for her since they destroy root systems...Would diatomaceous earth be helpful or does someone know of other options or helpful sites? Thanks!

Used diatomaceous earth for slugs before and what a waste of time and $$. You have to reapply after it rains and reguardless it didn't keep the slugs away one bit!

There are many many different varieties of nematodes that range from good to bad, some eat plants and others eat insects. The good news is that some of the predatory nematodes ( Steinernema feltiae for example) will eat the ones that attack your garden plants, all you have to do is introduce them into your garden. There are other microorganisms that will also prey on nematodes.

In order to minimize your pest problems it is necessary to have as many different types of microorganisms in your soil as possible,- we are talking many thousands of different species! This way nature can strike a balance between the good and bad, this is done by maintaining a good percentage of humus in your soil and NOT letting it dry out. This is easily accomplished by adding Compost and a suitable mulch.

Beneficial nemetodes will correct your problem if that is indeed the problem.

Get a soil test to see where the imbalances are in your soil and see if the lab will check for soil fauna (nemetodes, among other things).

D.E. will not work.

Chiten is supposed to help with nemetode probelms as well.

Where should I take a soil sample?

Well it sounds like Petersen's guide to N. American insects may be helpful...and I am thinking of taking Botany this semester unless another class would be more beneficial?

My grandmother has been composting for the 20 some years she has lived on this land and appears to have nice loam/sandy soil but introduces the kitchen scraps into the same general area of 1/3 acre.

Appreciate the info and any other insight!

Is D.E. very useful for above ground pests?

You want to take several soil samples to make up the sample you send in. Most soil testing companies will include instructions on how they want the sampling done.

That said, basically you dig a hole with a shovel or trowel and take a bit of dirt (say 2 tablespoons) from the center of the clod you just dug up. Do not include any sod in a sample.

I use a core sampler that is a hollow metal tube you jab into the dirt and when it is drawn out a core of soil comes up with it. The sample is taken from the center of the core. This is much easier than using a shovel or trowel.

Take several samples so you end up with 2 cups or so of dirt. Mix that dirt together and take a TBL (or whatever the instructions call for) out of that and that is the sample. This is easier done than said.

I'm not up to the limit on exactly what a nematode is, but I've been told that planting marigolds among your tomatoes,for instance, reduces nematodes drastically. All I know for sure is that since doing that, I have almost NO tomato damage and I see only about one or two tomato hornworms per year instead of the twenty or more I used to have. Besides, it's pretty. It's something about the smelly secretions of the marigold into the soil.