If you’ve ever tried your hand at growing heirloom tomatoes … then chances are you’ve run across Early Tomato Blight.

Early tomato blight is a fungal infection on the tomato leaves

Early tomato blight is an infection (caused by the fungus Alternaria solani) that starts out as dark brown spots, yellowing leaves, and eventually spreads quite rapidly through the crop killing the leaves and fruits if it has a chance. The fungus spores form in hot, humid weather and then wait for a nice, cool, wet evening to start destroying the plants. We’ve definitely had more than ideal weather for blight this summer. It shows up just as the plants are starting to set fruit – and once the infection starts, it is nearly impossible to stop from spreading. If you’re growing organically and aren’t planning on dousing them with fungicide, that is.

The fungus overwinters in the soil and any garden waste that wasn’t cleaned up the previous year. We didn’t do a very good job cleaning out the garden last fall, which probably helped lead to this outbreak. I’ve also read that it can travel through the air – and I drove by a house down the road that has a bunch of tomatoes in those upside-down hanging pots – and theirs all have blight as well.

Early tomato blight

There are some blight-resistant tomato varieties, but supposedly they are lacking in flavor. Unfortunately, the heirloom tomatoes seem to be most prone to blight – and of course, every tomato plant in our garden is an heirloom variety. In this case (fortunately) it has only affected the leaves so far – the fruit seems to be untouched.

So, what to do, what to do? There are some “organic” copper and sulfur sprays that supposedly help control blight – but they still have a novel of cautionary statements on the label, and that’s not exactly my cup of tea when it comes to growing things that I’m going to put in my mouth. Since I’m not about to douse the garden in fungicide, and I’d like to at least try and get a few tomatoes this year… I pulled out my scissors and spent the better part of a day painfully removing every single infected leaf. This is very, very sad:

Tomatoes after removing every blight-infected leaf

And now, I have tomatoes that are probably going to be sun-scalded unless they start making some new, blight-free suckers and filling in leaves. I need to pick up a few bales of straw or find someone with enough grass clippings to use as mulch, too. I guess now we just wait and see… hopefully the fruit on there now will ripen, and if the blight doesn’t come back we still have two months for them to grow.

Tips for next year: Blight can also be transmitted through seed, and so this means that I may just have to give up my 6th generation Amana Orange Tomatoes next year. Or, maybe I’ll try planting one or two from last year’s seeds in large pots on the other side of the house, just to see if they’ll stay blight-free. Fall garden cleanup, and crop rotation are definite musts. Fresh seeds and <shudder> possibly looking into some blight-resistant F1 varieties may be in order.

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8 Responses

  1. Lois

    I loved your pictures! My tomatoes looked exactly like that last year, after I did the same thing. I did get some fruit. Now, as the fruit is just setting, the lower leaves show the same spotting and yellowing. So, again, I cut off each “bad” leaf, but I am also spraying with liquid copper fungicide. It is organic, and it may help to save the plants. When it gets on the stems, it gets iffy, once you see it on the fruit… pull the whole plant and put in garbage bag. This is my third year with this! Good luck to you.

  2. Hi Lois,

    The blight is back again this year. We have two tomatoes in pots up on the deck, and so far they don’t seem to be affected. I just cut off all of the bad leaves, and am going to pick up some copper fungicide as well. I”m not sure if there is a good way to get rid of it, once it sets in. If the plants on the deck aren’t affected this year, then I may take a year “off” from garden tomatoes, and try them only in pots.

    If it’s just in the air… then there’s nothing much to do, besides plant earlier varieties. Good luck; I hope yours clears up too!

  3. andrea

    I realize this post was written two years ago, but I wanted to reply anyways. Your information was the best I could find on the web! I am fairly new to gardening and found my self with a huge crop of heirloom tomatoes all looking sad. I am off to the garden now with clippers in hand to and save my precious tomatoes. Thank you for the easy to understand and to the point information!

  4. I’m glad this information helped you! Three years later, we are still struggling with blight. I’m hoping to try some preventative measures next year…if it works out, we’ll keep you updated!

  5. Kat

    Hi, we are battling this right now–is the fruit from the vines still edible? We’re still getting flowers & tomatoes, although few, & the whole plant seems effected with blight. Thanks!

  6. Yes, the tomatoes are still edible – as long as they aren’t covered with black spots themselves.

    We’ve been dealing with this for years. It hasn’t gone away, and from what I’ve read it really doesn’t go away. We just cut off the blight leaves as soon as we see them, and hope for the best with our tomatoes. I have found that spacing them out more and growing them on trellises (as opposed to cages) helps with air circulation, and cuts down some on the blight. We end up with a bit shorter season than we would like, but still enjoy our tomatoes!

    Next year we are thinking of only planting tomatoes in pots with new (sterile!) soil, on the opposite side of our yard to see if there is any change. Good luck!!

  7. Sherry

    Hi I am new to organic gardening this year. Haven’t had any garden for about 8 years, this year We built 2 4 by 6 food red cedar deep raised beds. Filled it with clean soil from Lamberts and ohio earth organic compost. Used ohio earths fertilizer too which is omri certified. Beautiful heirloom tomatoes and beans and cucumbers all from organic seed that I nursed in home under lights march to May. I knew my eagerness to plant a large variety of tomatoes was a little overkill but planted them 1 foot apart! Wow did they ingulf each other as late June,july t
    Rolled in .I believe the blight which started in on them about 3 weeks ago was due to my overwatering and they’re cramped style of living. I still have harvested about a lg bushel which I have frozen that are big tastes and beautiful half bushel that was spotted and pitched them far away from the garden as well as the sick leaves. I don’t know if my soil will be bad next year or not as it seems to have spread through a lot of the plants. What are your thoughts on this as I really want to go bigger and better next year 3 feet apart and less watering ?

  8. Hi Sherry,

    Unfortunately I really think you are stuck with the blight 🙁 It could have come with the soil – even clean soil – or traveled through the air. If it truly is blight, then it is a fungus that has already spread to the soil. Planting tomatoes in the same soil next year will likely lead to blight as well.

    My advice is to go ahead and try planting more next year – if you are putting in more beds, then plant the tomatoes there, and other veggies where your tomatoes were this year. Space well and add a lot of mulch – and try to keep all of the leaves on your new tomatoes off the ground. (Cut off the bottom leaves if they are dragging on the dirt).

    Good luck!!

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