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QUESTION: Help! Nematodes Are Killing My Beloved Tomatoes

comments (6) August 14th, 2010

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surfgirl surfgirl, member
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Not surfgirls photo, just another forlorn tomato patch.Click To Enlarge

Not surfgirl's photo, just another forlorn tomato patch.

Photo: Ruth Dobsevage

Okay, so I'm only a second season backyard gardener and for gardening info, I'm based in Southern California, a few blocks from the ocean. We put in two 4x6 beds last year and had bumper crops, including one plot of only heirloom tomatoes. We put in the same this year, early April, and had fantastic growth with our Cherokee Purples, Brandywines, and three different Black Russian varieties. WE've had another great crop yield this summer, until recently, when suddenly all the lower leaves started dying out, then the tops toppled over, blah blah blah, long story short, at the insistence of the local nursery I pulled out one tomato plant today and voila, it has nematode roots. The nursery tells me I cannot plant tomatoes in that plot for TWO years. TWO YEARS? I am devastated.

I've looked online, and most of the posts I found are about remedies like soil solarization and various home remedies like mustard powder and sugar water. What I did not see, was any backyard gardener posts regarding beneficial nematodes, which is what my nursery recommends.

Another thing I don't understand is this - if I use solarization, marigolds, or beneficial nemotodes, why can't I re-plant tomatoes in that plot next Spring, provided I don't plant similar plants between now and then? Wont all the "bad" nematodes be gone then? I'm so bummed out because the only reason we put in the garden was to grow tomatoes...and they grow so well here.

I am trying to determine which is the most effective way forward, that would allow me to plant tomatoes in the ground next Spring.  Do I plant wall to wall French Marigolds right now, and then after they're finished blooming, do another crop of Marigolds, then treat the soil with beneficial nematodes before my Spring planting?  Or do I treat the soil now, with beneficial nematodes?  Or do I do a combo of solarization, marigolds and beneficial nematodes?  I'm lost as how best to proceed, in order to be able to plant my heirloom tomatoes next Spring (I am not interested in hybrid tomatoes even though they are hardier and can be nematode-resistant).

Any thoughts or suggestions are welcome. I'm going to pick all the remaining fruit tomorrow and then pull and bag the plants for the garbage. So I'm considering doing the beneficial nematode treatment on Sunday...unless anyone here has other suggestions...thanks!


posted in: tomatoes, pests, nematodes

Comments (6)

Beachsideliving writes: I just joined this website, so maybe you've all figured out the nematode problems. As a Master Gardener, we've been told to amend and constantly enrich the soil. Nematodes do not thrive in rich soil. My soil is pretty poor -- mostly sand, so I do a lot of container gardening; however, I've even had nematodes in my raised veggie bed and large containers!
I believe they were introduced with the plants I bought. I've also been told that if you plant okra, it acts like nematode candy; they love those roots. I'll be putting in some more tomatoes this fall and hopefully, they'll do better?

Posted: 10:04 pm on August 26th
Laara12 writes: If tomatoes are your passion, you could also consider grafting onto disease resistant rootstock. Betterheirlooms.com website sells tomato grafting supplies specifically for home gardeners who grow heirlooms. The Maxifort and Beaufort rootstocks are both resistant to nematodes. Good luck!
Posted: 12:14 pm on March 30th
AlOlmstead writes: At 71, I'm a beginner at vegetable gardening; but I have benefited from discussions like this and this is what I am trying now.

First, you're right about spending a fortune on soil, especially since our West Texas soil is practically pure clay; but the quality of commercial garden mixes is much degraded and so I decided to invest a year in soil reconditioning before trying to plant veggies.

Second, owing to risk of infestation and in view of physical limitations of my age group, I created "units" of reconditioned soil in raised beds measuring 2'x4'x8". If serious problems should appear in one bed, it gets tossed immediately with a minimum of lost investment. The beds sit on black plastic weed block under 0.5" wire mesh (to block ground critters). A bottom-up watering harness includes an array of 4 pressure-regulating 0.5 GPH emitters per SqFt (32 per bed). Burlap cloth prevents soil from clogging the emitters. Atop the cloth, 1 CuFt of Canadian sphagnum peat moss rapidly absorbs all of about 15 minutes of watering (no run-off) per watering session. The rest of the bed (about 4 CuFt) is filled with garden mix that slowly wicks water up from the peat moss.

Third, I opted for both French marigolds (tagetes) and pot marigolds (calendula) as my "first level protection" from a wide variety of plant and animal pests, even though that means that I cannot use beneficial nematodes. I add edible diatomaceous earth (from food wholesalers) to eliminate grub worms and a wide variety of insects with exoskeletons. Baking soda mixed with ground rice (use a small coffee and nut grinder) eliminates the several varieties of ants, including fire ants, that plague us here. At the end of their growing, all marigolds are mulched back into the soil. I have been told that the soil will remain pest-resistant for up to three years.

Fourth, since marigolds adapt to pH variations, each bed can be prepared specifically for 5.0, 6.0 or 7.0 veggies. And don't forget to add just enough earth worms (not "red wigglers") to reprocess the entire bed by end of season. Since the watering harness is on the bottom, they are not ripped up when amendments are added from time-to-time with hand tools.

Since, in Zone 7B, we have two growing seasons, the beds from the warm season are ready for cool weather veggies. There is still enough warm weather for more beds to be prepared during the cool season for use for in the following warm season crop.

I intend making liberal use of companion planting (especially with alliums--every sort of onion, garlic, etc.--wherever appropriate because I love them).

So, that's my plan for remanufacturing and maintaining the most expensive investment in gardening, organically pest-free soil. Comments from those who have "been there, done that" will be appreciated.
Posted: 3:51 pm on January 20th
IhateBugs writes: I, too, have problems with nematodes where I plant tomatoes, okra or eggplant: all in the night-shade family. I have a small garden, but try to rotate the crops so it is at least two years before any of these plants are sown in that row. I have a spiral notebook and indicate what I've planted from year to year.

About a cover crop of French marigolds...I've heard about that suggestion too, but never had the room to try it. I may try to order some beneficial nematodes with your good suggestions.

One year I got so frustrated that I dug a trench down the infested row and used old paper towel rolls, toilet paper rolls, and wood logs and trimmings from our trees to burn. (BTW, I had the water hose ready in case it got out of hand..ha.) It produced a lot of ash and I dug it in deep. I was mainly thinking that maybe the high heat might kill some of them off...I can always add compost, cow manure, etc. later. I then planted southern peas, sugar peas or beans to enrich nitrogen back into the soil in that row. It seemed to help.


Posted: 2:41 am on September 30th
surfgirl writes: sam, thanks so much for your reply and for sharing your experience with beneficial nematodes. I went back to the nursery yesterday and asked them why I cannot do a layered approach and their answers were interesting because I've only heard people recommend this or that approach but not WHY one or the other. Here's what they said:

1. Solarization kills everything in the soil, so if you have otherwise good soil, not a good way to go (and we spent a fortune on good soil).

2. You can use the Marigold approach, but Marigolds only drive away/repel both good and bad nematodes. They will only go deeper into the soil and when they "smell" the tomatoes next Spring, they'll come right back up to attack them.

3. Beneficial nematodes are the only thing that will actually get rid of bad nematodes. And you cannot combine them with Marigolds because the Marigolds will drive away the good nemas.

So, I'm going to roll with the beneficial nemas - adding them into both beds this evening, and then in a couple of weeks I'll put in non-nema loving fall/winter crops like Broccoli, peas, maybe cabbage and lettuces. And then in the spring I'll re-treat/re-apply the beneficial nemas again when I put in my tomato seedlings. However, next year I will not use the same bed for the tomatoes, I'll move them to the other bed. And reverse that each year. Hopefully that will work.

Sam, I think you are better able to get a handle on your nemas because your tomatoes are in pots. I may have to do that if this scheme doesn't pan out. We'll see what happened next year. Thanks again for your thoughts! It's really more heartbreaking than I thought, having to pull out 12 heirlooms when they were giving us such amazing fruit this year...Oh well, live and learn, right?
Posted: 3:43 pm on August 15th
samlongchef writes: I have had great luck with beneficial nematodes and a nagging grub problem in my front lawn. I'm not sure why you were advised to wait so long---two years---before planting again. I grow my tomatoes in pots to avoid a "permanent" soil problem like you are experiencing, but I'd say roll with the beneficial nematodes, plant a "cover" crop of marigolds, turn those under, plant another, and move forward with your heirlooms next spring---which I grow and love so well myself. Re-apply more beneficials in the spring, turn your soil really well, add all kinds of organic matter to boost its health, and go for it!
Posted: 2:36 pm on August 15th
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