I heard a lot about nematodes when I first started gardening in our present location in California. It seemed primarily to be directed at fruit tree root problems.

I was never aware that vegetables were affected, but perhaps it is because the newly popular way of raising veggies on small suburban plots - is in boxes. These boxes are made up mostly of "created" soils - such as compost, peat, organic fertilizer amendments. This could presumably - help to eliminate the inherent soils contribution to the problem.

On the other hand, fruit trees rarely have this advantage.

That is one reason that fruit trees are grafted to apricot root stock - as it is believed that apricot root is a deterrant to the nematodes.

Just my 2 c's.

Bejay

I haven't heard of the citrus solution either. I seen a lot of sources that say french marigolds, grown as a cover crop, has been touted as a way to reduce their populations and help improve a site. Castor Bean is another one that is supposed to be bad for them, but I haven't heard as much about it.

I would rather have the knotty problem of the knots than castor beans. They love our climate, and become a real nuisance - re-seeding everywhere. Not only that, but the bean is poisonous.

Can't keep them out of the yard once they are established, and must have pulled thousand seedlings so far - no exaggerations. They should be outlawed here.

Bejay

Citrus sounds right to me--many new organic insecticides are made from citrus oil extracted from the pulp. My own experience is with lemons & dog fleas--kills em graveyard dead. I run citrus peels through the blender & pour in my raised beds cuz I don't till.

So do you have sandy soil? When I think of Houston, I usually think of clay but I do know that there are relatively sandy areas.

Have you tried growing Elbon Rye in the fall? Also nematodes don't do too well if the area contains too much moisture. Try really putting alot of organic material in the soil so it holds water.

I've also had good luck with Actinovate. The upside is that it can help control other soil borne diseases too.

Here is a link that might be useful: Nematode study--East Texas

Oh man! Do I hate RKN!! Just about every year I lose a bunch of bean plants to them. The plants start to wilt, you water, they wilt more, you water. They die! The roots on the bean plants are gone and all you get when you pull the plant out of the ground is a little stick! Aaargh!!

A few years ago, I started another bean patch over and away from where I had been growing them normally. It helped for a year or two and now I see a few plants doing the same thing as what they were doing in the first planted area.

Someone mentioned putting down black plastic over the soil for a season. Would heat up the soil to the point of killing the RKN. Haven`t tried it yet because I hate not being able to grow veggies during the summer months.

Big problem at my florida place. Rotation is the key. Do not grow the same vulnerable crops in the same area over and over. Introduce as much OM as possible, mineralize, and rotate heavily with legumes. Make sure to inoculate the legumes. A lot of the common vegetables are very vulnerable: tomatoes, peppers, brassica, as examples. Much less vulnerable: cowpeas (especially of the legumes), okra, pigeon peas, peanuts, potatoes and sweet potato.

Greatly enriching the soil is the best cure and in hot sandy ground that is the hard thing to achieve. Rotating beds back through an adapted grass helps too, and is a lot more achievable than raising fertility very high.

I was told to use clear plastic by the Univ. of Fl. This will help kill the nematodes, weed seeds and diseases in the soil. Yearly rotation is very important. I know it is not always possible. Maybe you can grow in containers for a year instead?

As pnbrown said - soil enrichment/amendment is the key. Especially with high quality compost. Some studies show that adding dry molasses to the compost or tilling it into the soil will also adi in reducing nematode populations.

Dave

I don't have sandy soil, but I have RKN anyway. Bummer. The Houston area is mostly clay, although we have little steaks of sand running through it. We call it gumbo or black and white soil around here.

I've spent the past year amending the soil with compost already, but the nematodes are pretty bad. My standard veggie fertilizer is a compost tea/molasses blend, too. My thinking for now was to do the following:

1) treat with citrus
2) Wait a week and then plant something resistant over winter (I read broccoli does okay - my plan if I can find transplants)
3) Solarize with clear plastic in July and August
4) Maybe treat with citrus again before planting next fall.

I've thought about trying the Elbon Rye, too. Maybe that'll be next year. Nothing did well this fall. I will say, though, that my banana peppers produced like crazy all summer, right in the middle of the RKN spot. Love those banana peppers!

You might want to stop buying transplants. I'm pretty sure that's where I got my nematodes.

Up here in DFW we have Houston black gumbo too and I think I got nematodes from some lettuce transplants. Please consider the Actinovate if the citrus doesn't work. After tilling in two years worth the leaves and compost and using it, I seem to have gotten rid of them. This year I've had no sign of them at all. Maybe they drown from a wet spring since they don't do well in wet soils.

I don't use many transplants, and in the areas I have them the worst I've never planted transplants. I'm new to this house, though, and I know the previous owner had a veggie garden in the same area - I have no idea how she gardened. I was just thinking it seemed a little late to be direct sowing anything.

Anyhow, I will look into Actinovate. I don't know much about it and haven't had time to do much research, but what I've read so far sounds promising - thanks for the suggestion.

Since heavy soil hangs onto OM, I should imagine it is much easier to eliminate bad nemos than in super-sandy soils. Maybe dry hot conditions are slowing the breakdown of OM?

Nematodes are microscopic. I don't think you can drown them. You can still plant lettuce,collards, kale and swiss chard from seeds by direct sowing.