An Uncoventional Organic Method for Killing Root Knot Nematodes

As you may have read in a previous post, root knot nematodes recently became public enemy number one in the Hanbury House vegetable garden.  I was kind of depressed about it for a few days, struggling to decide what the best coarse of treatment was, if any.  Being a home gardener, especially an organic one, there are few options for dealing with nematodes in the soil.  One of the most commonly recommended organic methods to kill them is solarizing the soil, covering the area with plastic for 6 weeks to allow the soil to reach 120 degrees for an extended period.  The area has to be in full sun for it to work.  My particular veggie bed is only in full sun a few months out of the year, in the height of summer.  I am patient and could wait until then, but according to what I have read in some master gardening publications, solarizing is less effective near the coast where summer temperatures don’t get sufficiently high.  Our summer time highs are rarely over 80 or 85 degrees.  Great.  In all likelihood, it will not get hot enough to kill the little buggers in my coastal Southern California backyard, even in the summer.

alternative to solarizing hot water to kill root knot nematoads

I spent the day boiling gallons of water to try to the kill the nematodes organically

I need an affective organic treatment for nematodes that works in the cooler seasons and in less than full sun situations.  After a bit of research and a suggestion from Patricia at the end of my other post, I decided I might as well give boiling water a try, especially since I will have to wait many months before trying solarizing.  In the past, I have managed to kill a few weeds with boiling water, and I am hoping it might also work against the root knot nematoads in the garden.  There are lots of dept. of agricultural resources that mention hot water above 120 degrees has been affective at eliminating nematodes on the root ends of bulbs, banana plant roots, hostas, and other green house plant’s roots.  Hot water seems worth a shot.  Depending on the crop, the plant is left submerged a different amount of time.  The publication about the banana plants said 30 seconds was sufficient to dip the ends of the plant and kill nematodes, but the one about bulbs said ten minutes.  I have no control over the time it takes to soak in, but if it starts out at boiling, by the time it cools down to 120, it should have had plenty of time to work and soak down in.  Boiling water is relatively cheap, non toxic, and easily available, so the worse case senario would be it doesn’t kill the nematodes.

I spent the better part of my day going back and forth between the back garden and the stove, dumping gallon after gallon of hot boiling water on the veggie bed.  At any given point, I had three different pots and kettles going.  Now the bed looks like warm steamy mud.  I sure hope it helps, and I will report back in a few months on whether or not boiling water was effective way to kill root knot nematodes in the garden.  Wish me luck!

I have a long wait until summer, and if you know of another organic solution to root knot nematodes, I would love to hear about it.  I’ll give anything a try.

* This post is linking to a Blog Hop over at Sunny Simple Life blog and The Self Sufficent Home Acre

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An Uncoventional Organic Method for Killing Root Knot Nematodes — 16 Comments

    • Thanks, I hope it works too and that it is not an increasing issue. I have seen a lot of SoCal posts from other garden bloggers having similar issues with root knot nematodes in the last couple of years. I am not sure if I have been lucky all these years and root knot nematodes are actually common in southern California, or if one of the tomatoes or peppers I brought last Spring introduced them into the raised bed. The one carrot is all I have seen nematode nodules on, so I am hopeful I will get them eliminated.

  1. Have you tried marigolds? Look into it. They need to be grown for at least 2 months fairly dense and then turned into the soil for best protection. Of course this leds to more marigolds if you don’t dead head…but it gets rid of nematodes… and looks nice. Don’t fall for the gimmicks either all of the marigolds work some jsut work better than others so go with what is cheap and easy to deadhead.

  2. Lianne, you’re a smart cookie so I assume you’re already aware of this, but make sure that you don’t cross-contaminate other soil in your garden with the nematode soil by using garden tools/gloves/etc that could spread the little buggers around. After my solarization failed and marigolds made little to no dent, I decided to try VFN seeds, which are nematode resistant. Of course your variety is greatly limited, but at least it’s an option. I have a huge list of tomatoes that are resistant and even researched some pole beans that handle the nematodes well (Rattlesnake, Blue Marbut and Alabama #1).

    • Thanks for the tips, Jessica! I appreciated that you shared all your own experience with nematodes on your blog, the bountiful backyard. I didn’t feel like I was alone in this battle and it gave me hope.

      Once I noticed the little buggers in on the carrots, I started being careful about sanitation of my gloves and tools used in there. Unfortunately, if they got out and around before that from my stuff, there is nothing I can do but wait and see where the turn up. I am optimistic since I have not seen any damage or signs of them elsewhere that they were pretty isolated in there. I am also keeping my fingers crossed that the boiling water may have helped. I even dumped my giant pot of left over boiling water from my strawberry kiwi jam canning in there when I was done.

      In the past, I have always made sure to get tomato varieties with a “T” in the their disease resistance coding since my hubby mistakenly introduced tobacco mosaic virus in that part of the yard, almost 15 years ago. He made some crazy homemade plant “tonic” recommended by Jerry Baker, a self proclaimed master gardener, who once had shows on PBS. It was called tobacco tea. Bad idea. I haven’t seen any signs of the disease for 10 years, knock on wood. Anyway, I appreciate the tips and will look for tomatoes and beans that also have N in the disease resistance code. Thanks!

    • An update on Nematodes:
      Back in March, I planted 3 tomatoes in the bed that had nematodes and was treated with a deep soaking of boiling water. Only one of them is listed as being nematode resistant. So far, so good. None of the tomatoes are showing signs of infection from the little buggers. All are healthy and growing, but time will tell if the boiling was truly successful in eradicating the nematodes. I figure once the heat of summer kicks in or the tomato season ends and I remove them to see the roots, I will have a better idea if it worked or not.

    • Thanks for the compliments on my stove. I love the stove, despite the fact it doesn’t have all the modern conveniences of convection or precise temp. It is actually my second vintage 1940s stove. When we used to live in a little duplex a few miles from here, we had one we bought from a friend for $40. We planned to bring it with us when we bought a house 3 years later, but this house still had its own original 1944 stove, plus it was bigger and had be recently serviced. We specifically requested it when we put in the offer on the house and later gave our first one to another friend.

  3. I’m glad it helped, I’ll keep my fingers crossed for you. I also have a blog on wordpress and tried to follow you but for some reason it’s not coming up on my reader. If you have a chance, I would like to know the differences between Silkies and Cochins. I raise Silkies in my backyard garden, but find they’re somewhat delicate as far as health is concerned and was thinking of switching to Cochins.

  4. Hi, I’ve spent way too much time on your site, but so fascinating 🙂 Wish we could meet. I’m coming to LB for a Peace Initiative Meeting & Fair @ the convention center, 10/26, then off to my daughter’s new home in Anaheim to help w/ her garden. Found your site searching for good S CA plants (I’m from Bodega Bay, CA). My daughter (Nicki) also loves the vintage look & is new to gardening. I ‘spose what grows for you may not work in hot Anaheim but I’ll show Nicki your site for ideas:) I’m bringing her a sword fern to try in shady area, lavender, possibly nasturtium starts & an abutilon. Do you have any advice?

    • Hi Karen,

      Thanks for the compliments on my blog.

      I grew up on the border of Anaheim, a few miles from Disneyland. Most parts of Anaheim have a similar climate to my neck of the woods. I am in Sunset zone 22 and a lot of Anaheim is as well. Some parts of Anaheim are in zone 23, which isn’t drastically different. I think your daughter will be successful with all those plants you mentioned.

      A good book about growing a garden locally is Southern California Organic Gardening by Pat Welsh. It is a month by month guide of what to plant and where. Another of my favorite local gardening books, that is out of print but can be found at, is called 52 Weeks In The California Garden by Robert Smaus. Both are a wealth of information on edibles and ornamentals that do really well in SoCal. Best wishes for your daughter in her new home and I hope you visit my blog again.

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