I have RK nematodes-thinking of replacing soil in raised bed
 

I was taken by surprise this weekend! I have a raised bed that runs the down the side of my house. It faces south-west and has some of the best light in my yard. It's prime tomato bed for me. I'm in the process of bed prepping for plant out. I pulled the last three neglected tomatoes and found the roots to be thickened and bearing a few knots each. This bed is mostly cheap, nasty top soil. We built the bed and filled it cheaply because we didn't know any better at the time. I've been amending it but now I've got some nasty beasties. Hybrids do fairly well here, but not OPs/heirlooms. I never understood why. So now I'm left with a decision. RKN are a pain in the backend to kill from what I've seen on Tville and around the web. That bed holds around a yard of soil so I think I'll just change it out. I'll do half horse manure/veggie compost and half something else (I'll have to think on this) with a layer of leaves and maybe dried molasses at the bottom of the bed just to give the good critters something nice to snack on. I won't put any sand in the bed. I can't control what is below the raised bed. Our neighborhood is built on an old horse pasture. There is a very thin layer of native soil/sand over lots of caliche.

This course of action seems logical to me. I think I would spend about 30-40 bucks on the new bed and would get immediate and hopefully lasting results. I've got a new compost area started in my yard so I'll have lots of leaf litter to add in next spring. If nematodes hate organic matter and love sand so much, I think I can take care of that. Has anyone else tried something like this? A local garden center said I should just get some beneficial nematodes and that would take care of my problem, but I'm not so sure about that. I haven't found any info on beneficial nematodes killing RKN. Actinovate looks like it will help, but I was going to use that anyway. I like the idea of a cover crop but it seems I need to take more drastic, immediate action. I would love to get other thoughts on this.

Christy

We have them so bad in Florida that no who plants in the ground escapes them no matter what. Nematode resistant varieties do pretty well. I now use earthboxes and growboxes.Initial outlay of cash but the plastic wont degrade in the sun so they last for years. RKN has become a non issue.
-Marsha

I honestly don't think there is a quick fix for getting rid of root knot nematodes in raised beds. I'm trying to improve my soil to the point that I have healthy soil that attracts beneficial microorganisms which will hopefully keep the RKNs under control but I expect that to be a long term process. Meanwhile I'm planting nematode resistant vegetables, including hybrid tomatoes, and cover crops that control RKNs But, like Marsha said, use of earthboxes or similar containers is probably the best way to grow OP/heirloom tomatoes.

I have the same problem (RKN). This year Im grafting Heirlooms onto Better Boy, SuperSweet100, and Celebrity to see if that will help. Also, I was thinking about planting the area in Marigolds to see if that can drive them away at least temporarily. Burpee sells a variety called Nemagone, not sure if its more effective than any other variety. Hopefully someone knowledgeable will chime in.

I interplanted Burpee's Nema-Gone Marigolds with heirloom tomatoes this past season and still had serious RKN problems with the tomatoes. Also, the Nema-Gones grew quite large for marigolds -- almost as high as the tomatoes. I won't be interplanting them with anything soon but might plant them as a cover crop someday. This past year I planted Dwarf Essex Rape during the fall/winter and Sunn Hemp during the summer for cover crops -- both are supposed to suppress RKNs. I have not used marigolds, rape or hemp long enough to judge whether any is effective in controlling RKNs; however, I do like the looks of the soil after I turn the rape and hemp under plus they don't go to seed too soon like marigolds do. Thus I will continue to use them as cover crops in beds where I see RKN problems. I believe the best way to get RKNs under control is to develop healthy soil containing lots of organic matter and refrain from planting things that attract them (like heirloom tomatoes, okra, squash and cucumbers) until I get the little buggers under control which I expect will take a while.

had the same problem few years back. after growing season, i added 40 pounds of very small pine bark chips. my box is about 70 square foot. i mulched the plants growing that year with hay or straw. i tilled in hay and pine bark with exsisting soil. i then watered it in real good. bed is empty by the way, no plants. i then covered the bed with thick construction grade plastic. my bed is about 24 inches high. i then cut the plastic to fit the bed . stapled plastic to wood bed. soil and top of bed was totally covered by plastic. did this mid july and didnt remove plastic until mid sept. dirt got very hot under plastic. 6-7 hours of full summer sun. it gets very hot here during those months. removed the plastic in september. did not do anything to the bed until next mid march, when i planted tomato seedlings. best tomatoes i ever had. i have not seen any signs of nematodes on the roots of the plants i removed last year. if they pop up, same treatment. any questions dont hesitate to ask. good luck

[QUOTE=ssi912;322275]had the same problem few years back. after growing season, i added 40 pounds of very small pine bark chips. my box is about 70 square foot. i mulched the plants growing that year with hay or straw. i tilled in hay and pine bark with exsisting soil. i then watered it in real good. bed is empty by the way, no plants. i then covered the bed with thick construction grade plastic. my bed is about 24 inches high. i then cut the plastic to fit the bed . stapled plastic to wood bed. soil and top of bed was totally covered by plastic. did this mid july and didnt remove plastic until mid sept. dirt got very hot under plastic. 6-7 hours of full summer sun. it gets very hot here during those months. removed the plastic in september. did not do anything to the bed until next mid march, when i planted tomato seedlings. best tomatoes i ever had. i have not seen any signs of nematodes on the roots of the plants i removed last year. if they pop up, same treatment. any questions dont hesitate to ask. good luck[/QUOTE]
Yes that technique is referred to as solarizing and it works very well. Some worry that it also kills the beneficials living in the soil.
-Marsha

Thanks to everyone for your responses. I had a nice conversation this morning with a gentleman at one of our better nurseries. He recommended putting fresh dirt in the bed. For now, my plan is to replace the dirt. Going forward, I'm going to take a no-holes barred approach. I'll be working lots of organic matter in every season, I'll probably just do a spring garden and let the bed go fallow during the winter except for a cover crop like mustard, I'll be inspecting the roots more closely on every plant I pull up to catch problems when they start, I'll disinfect my garden tools when moving between garden areas, I'll use beneficial nematodes/mycos/Actinovate, I'm going to try grafting some N tolerant rootstock onto some of my extra seedlings, I'll be researching nematocides for future use, as needed, I'm expanding my bucket brigade container garden and I'm trying a couple of N tolerant varieties of tomatoes just to see how the flavor compares to the usual OP/heirlooms. I'm hoping that with a multipronged approach, I'll be able to use my gardening areas for quite a while.

It looks like Florida has a huge nematode problem! If I have to only garden in containers in the future, then that's the way it goes. I'm going to put up a fight first since they haven't hit my main garden. I'm interested in the marigolds as a cover crop/companion plant but it seems they attract spider mites. I don't need anymore help in that department! I've read some other threads here with product recommendations for fighting the little suckers so I've got more ways to fight.

solarize! it works, i promise!

[QUOTE=ssi912;322443]solarize! it works, i promise![/QUOTE]

I would do this but the location of the bed isn't conducive to solarizing. The bed is at the side of the house and the soil wouldn't get enough direct sun to heat it, I'm afraid. Gotta love zero lot lines! I can grow tomatoes reasonably well due to a couple of factors. However, it is in no way an ideal place to grow tomatoes. Sadly, it's the best I can do at this house.

There is a variety of RKN resistant red clover from university of Florida you can plant in October for winter cover. It is called Southern Belle and is specifically bred for the deep south.

I say dig up the infested soil and haul it off.

Then spend the $40 a yard on good soil.
To me this is a no brainier.

Worth

Since your infected soil is in a raised bed, not a container, wouldn't the nematodes just re-populate the bed from the soil underneath?

[QUOTE=Stvrob;322460]There is a variety of RKN resistant red clover from university of Florida you can plant in October for winter cover. It is called Southern Belle and is specifically bred for the deep south.[/QUOTE]

Thanks for the info. I'll look into this.

[QUOTE=Worth1;322463]I say dig up the infested soil and haul it off.

Then spend the $40 a yard on good soil.
To me this is a no brainier.

Worth[/QUOTE]

Exactly my thinking. I hope it's also a long term solution.


[QUOTE=nativeplanter;322502]Since your infected soil is in a raised bed, not a container, wouldn't the nematodes just re-populate the bed from the soil underneath?[/QUOTE]

This is a concern for me. However, the native "soil" underneath is really very thin. I'll try to take as much of that with me as I can. I'm going to try and go all the way to the caliche which shouldn't take much digging at all. Also, my thinking is that by replacing the infested soil, I'll be taking away their preferred habitat which is sandy soil. I'll replace the old soil with something that the nematodes will hate, a nice rich unsandy soil! That's why I'm also planning on lining the bottom of the bed with extra organic material in the form of leaves and dried molasses. I'll probably put a few other goodies in there before I add the new soil. It's not really a barrier since the nematodes are so small, but I'm hoping that I'll encourage more of the good guys to grow and colonize my micro-habitat aka new tomato bed. If at some point in the future I'm over-run by nematodes, I'll find another way around them. Right now though, I'm hoping this is a good bet and it certainly is the cheapest option. I'm hoping I stop them here or at least really knock them back, enough that I can have my garden and actually grow in it, too. I'm also going to be mulching the heck out of the areas around my garden, raised bed and containers. I'm hoping that adding organic matter everywhere in my yard will help improve the overall ecology of the soil.

I used to have nematodes so bad that only the hardiest hybrids would live long enough to produce and they would end up getting nematodes eventually. I can't remember who told me; but I was advised to put in as much fresh horse manure as I could and work it in. I did it a few months before planting and the nematode problem was reduced by at least 75%. I repeated that process the next year tilling it in well and giving it time to work and have had only the occasional tomato plant hit by them since then although I have only added composted manures since then. The biggest problem was mucking out horse stalls to get the fresh manure.

The nematodes that hit squash, cucumbers and okra must be different because I still had problems with them when my tomatoes were totally nematode free. For them I started by spreading sugar generously over the bed a week before planting and gently watering it in. I would then plant the Nemagone marigolds in between my plants and it seems to work. Last year I put down more sugar than ever before where I was planting my okra and then put a Nemagone on each side of every plant. That was the first year in over 35 years of growing okra that I didn't have any sign of nematodes when I eventually pulled the plants in the fall. I basically did the same with cucumbers and squash with equal success. Down here nematodes are so prevalent that pretty much all field grown tomatoes have to be nematode resistant to get a decent crop. I don't think what I did for my raised beds would be very practical for large scale planting; but it worked great for me.