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.
It looks like a simple solution to a big problem. Good tip to pass on.
Donna´s last [type] ..The Niagara Falls Garden Magazine for GGW and GBBD
Twitter: appalachianfeet
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 [type] ..How to Grow Tasty Citrus Outside in Zone 7+ (Tangerines, Grapefruit, Oranges, & More)
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 [type] ..The Goat Shed – Part II
Twitter: appalachianfeet
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!)
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.
Twitter: appalachianfeet
If you’re at 7, sounds like it is already in the ideal range. Do you end up with diseased tomato plants?
You are a clever lady. Raise the pH level, brilliant!
Janet, The Queen of Seaford´s last [type] ..Protection, Birds and Fun
Twitter: appalachianfeet
Well, I didn’t come up with it — but maybe I’ll take the credit, anyway.
Sustainahillbilly´s last [type] ..How to Grow Tasty Citrus Outside in Zone 7+ (Tangerines, Grapefruit, Oranges, & More)
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 [type] ..Tough Plants for an Easy Garden
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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 [type] ..How to Grow Tasty Citrus Outside in Zone 7+ (Tangerines, Grapefruit, Oranges, & More)