How to Prevent Fusarium Wilt on Tomatoes

Last season nearly every local gardener I know had tomatoes die from Fusarium wilt. We lost a large percentage of our crop to it (although with 80 tomato plants, we still had plenty to harvest).

Photo Caption: Peppers, eggplants, and potatoes are also susceptible to Fusarium wilt. In our garden, tomatoes are always the hardest hit.

Then I saw GOFO’s office garden at Crescent Studios and could not believe my eyes.  Unlike the other gardens I’d seen, their tomatoes didn’t have a single spotted leaf. These plants were lush, gorgeously green, and very productive. They were also intensively planted and had woven themselves into an impenetrable mat (air circulation? not really!) So why were these plants so healthy?

GOFO wasn’t sure of the secret to their success. It turned out that when they limed their soil to boost the availability of calcium it also happened to raise their soil pH to 6.5 – 7.0. Fusarium wilt prefers a pH under 6.5 or the spores have a hard time taking hold. After seeing the GOFO plants, I’m a believer! Winter is the perfect time of year to amend soil with lime so I’ll be having my soil pH tested through our local Cooperative Extension office in order to find out the application rate of pelleted limestone in my garden.

Fertilizers made with ammonium nitrate are another problem because they cause tomato plants to be more susceptible to Fusarium wilt. This isn’t much of an issue for organic gardeners, but click here to read about different forms of fertilizer including ammonium nitrate.

Another excellent option is to plant varieties that are resistant to strains 1 & 2 of Fusarium wilt. If a seed packet or catalog entry has an “F” it indicates resistance to Fusarium wilt. “FF” indicates resistance to both strains of the disease.

Photo Caption: Fusarium wilt is a vascular disease that causes leaves to yellow and then die. If plants wilt during the heat of the day even when soil is moist, this may be the culprit.

I find Fusarium wilt to be a bigger problem in my garden than the more infamous blight diseases because it destroys the plants before I get much (or any) harvest. You can read the blog post I wrote on how to identify this fungus vs. other early tomato diseases by clicking here.

Eliza Lord

I'm a Greenville, SC native (the Appalachian foothills) who wears the hats of Greenville Master Gardener & Upstate Master Naturalist. I love to write about food and sustainability.

14 thoughts on “How to Prevent Fusarium Wilt on Tomatoes”

  1. Donna - February 13, 2012 12:45 pm

    It looks like a simple solution to a big problem. Good tip to pass on.
    Donna´s last blog post ..The Niagara Falls Garden Magazine for GGW and GBBD

    1. Sustainahillbilly
      Twitter: appalachianfeet
      - February 25, 2012 11:20 am

      Thanks! Now if I can just follow my own advice… trying to make it to the extension office to order my soil sample before the season progresses too much to bother!
      Sustainahillbilly´s last blog post ..How to Grow Tasty Citrus Outside in Zone 7+ (Tangerines, Grapefruit, Oranges, & More)

  2. Curbstone Valley Farm - February 13, 2012 4:27 pm

    We were hit hard with Fusarium last year. Never really been a problem for us before, but our weather last year didn’t help. I didn’t lime, and in hindsight I should have, but we usually haven’t had to. Out of sheer desperation, as we plant primarily heirloom varieties that are highly susceptible to both Fusarium and Verticulum wilts, this year, we’re grafting to resistant root stocks. I should say we’re experimenting with grafting, as we’ve never done it before. I’ll start sowing our seeds in the greenhouse tomorrow. Any variety we graft this year, we’ll also plant a non-grafted plant to compare. I’m excited to see what difference it makes in plant performance this year. I just couldn’t bare another year like last year, I love heirloom tomatoes too much to have such a pathetic harvest. Crossing my fingers we both have a better year this year.
    Curbstone Valley Farm´s last blog post ..The Goat Shed – Part II

    1. Sustainahillbilly
      Twitter: appalachianfeet
      - February 25, 2012 11:21 am

      I’ve been intrigued by the idea of grafting too — looking forward to your post on it (I’m sure I can count on a great one!)

  3. Africanaussie - February 13, 2012 6:40 pm

    Very interesting. I live in tropical north Queensland Australia, and was told when moving here that there was virticulum wilt in the soil and I would never be able to grow any tomatoes other than cherry tomatoes. I use compost, comfrey and seaweed on my soil and the ph is always around 7. I am not sure that I should put lime on, as I dont want the ph to go too high. I will be interested to watch what your results are from adding lime.

    1. Sustainahillbilly
      Twitter: appalachianfeet
      - February 25, 2012 11:28 am

      If you’re at 7, sounds like it is already in the ideal range. Do you end up with diseased tomato plants?

  4. Janet, The Queen of Seaford - February 13, 2012 6:42 pm

    You are a clever lady. Raise the pH level, brilliant!
    Janet, The Queen of Seaford´s last blog post ..Protection, Birds and Fun

    1. Sustainahillbilly
      Twitter: appalachianfeet
      - February 25, 2012 11:32 am

      Well, I didn’t come up with it — but maybe I’ll take the credit, anyway. :)
      Sustainahillbilly´s last blog post ..How to Grow Tasty Citrus Outside in Zone 7+ (Tangerines, Grapefruit, Oranges, & More)

  5. Casa Mariposa - February 18, 2012 11:59 am

    I grew tomatoes last year that had been gifted to me from the Compost Angels and for the first time ever, I never had any disease. But I did add a few Tums to the planting hole before I transplanted my seedlings. A friend said she’d been doing it for years and it added calcium to the soil, which prevented disease. It worked fabulously!!
    Casa Mariposa´s last blog post ..Tough Plants for an Easy Garden

    1. Sustainahillbilly
      Twitter: appalachianfeet
      - February 25, 2012 11:35 am

      I wonder if tums also raise the pH… I think that is how they work on your stomach! Very amused by your generous “compost angels.” :)
      Sustainahillbilly´s last blog post ..How to Grow Tasty Citrus Outside in Zone 7+ (Tangerines, Grapefruit, Oranges, & More)

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  8. Michele Martin Seelbach - July 23, 2014 12:44 am

    We built a raised garden this year and followed instructions to establish a healthy tomato garden. We used packaged top soil, peat moss, and manure for the soil and purchased plants from our local farmer’s market. After 3 months of beautiful growth, we were so disappointed to find all of our plants have wilt disease. I have cut the diseased leaves and stems out of the garden in hopes of saving some developing tomatoes.
    What do we need to do to our soil next year to hopefully prevent wilting again.

    This was quite a blow as we have grown tomatoes in a large garden plot in our yard for 22 years and never had the devastation we have in our new raised garden.

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