Edible Gardening

Diseases of Tomato Plants & more


Herbicide damage on Tomatoes

Herbicide damage on Tomatoes

I have never seen a tomato plant look so funky –  deep green but with thick hard stems, dwarfed curled leaves and stunted growth.  Not the usual yellowing leaves with black spots so typical of tomato fungus or bacterial problems.  What happened? Tomato plants can get any number of pest and disease problems, and there may be similar symptoms with very different causes.

Herbicide damage via horse manure

In this case, it was clearly a case of horse manure tainted with a broadleaf herbicide. The older manure I used was OK as any chemicals it may have contained had dissipated, but the most recent load was too fresh!   Horses grazed in pastures treated with broadleaf weed killer and even after it went through the horse it was still viable!  Had I waited 9-12 months it would have been well composted, but I was in a hurry for “great soil”.  My only solution was to pull up the tomato plants (an some bean plants too) and start again in a different part of the bed that had not been so heavily amended.

For me, it was proof again that compost from my own leaves and grass clippings is still my most reliable source of organic matter for the garden.  The compost pile is “cooking”, helped along my beneficial microbes and a little molasses to help them multiply.

If you are wondering what might be happening with your own tomato plants, Colorado State University Extension Service has an excellent pictoral guide to diagnosing problems.  Click here for their website:  http://www.ext.colostate.edu/pubs/garden/02949.html

Note to Self…

I like keeping a GARDEN DIARY to help me remember when things bloom, when I planted seeds and when they came up or were harvested, what I need more of or less of next year…  My diary helps me plan, helps me be patient and confident that nature is working just as it should.

Notes to my diary this week:  The peonies have been fabulous and too quickly over.  I stored a few buds in the refrigerator for one last flower arrangement, but why? Did I really think I would run out of flowers? Now my Astillbe, Asiatic lilies and Larkspur are stealing the show.

I am picking sugar snap peas, arugula, and the first of the garlic.  10 Endive frisee was exactly the right number to plant so that I do not have to eat it every day before it bolts.  The green Kohlrabi comes up from seed much better than the purple variety and is best seeded in early April.  There were enough ripe mulberries yesterday for pie!  The asparagus is quickly turning into a thick bed of ferns.

More notes to share…

Breakthrough!  I found a solution to ridding my blackberries of the thrips that have ruined the fruit every year.  My brambles would bloom heavily, and then set fruit that would just dry up.  Thrips are tiny mites that live inside the bud of a flower or fruit so they are impossible to kill by spraying.  I found a systemic insecticide labeled for use on fruits (Home Depot).  It is used as a soil drench that is then taken up into the stems and fruit of the plant killing the thrips.  Fruit is edible 2 weeks afterward.  The insecticide is Imidocloprid, made from tobacco (nicotine) and is one of the least toxic insecticides for people.  It can be very toxic to bees if sprayed, but not as a soil drench. So my blackberries are not organic, but at least I will have them.

The potato plants have just started to fall over revealing new potatoes on the surface of the soil. Potatoes left on top of the soil in the sun turn green and inedible. I could have covered them with more mulch, but I decided that the best idea was to just EAT them!  The foliage is still bright green so it is too soon to dig the rest.

My Tuscan kale is huge, coming back strong after I cut the blooms off a month ago.  After seeing the cabbage butterflies last week, I anticipated the first holes in the kale from cabbage loopers , those green worms that so perfectly match the color of the leaves.  It is time to get out the BT (bacillus thuringiensis) spray, which works organically thanks to bacteria that kill only worms.

I sit here listening to this glorious rain, knowing that my garden is very happy.   Best wishes for your beautiful garden too.



6 Comments on Diseases of Tomato Plants & more

  • harriett riddle says:
    June 5, 2017 at 8:47 pm

    my tomatoes I bought from Lowes had about a thick stem and was kind of whitish from the dirt up. have lost about all of my tomatoes it was about one inch up from the soil, can u tell me what is wrong?


    • admin says:
      June 6, 2017 at 4:56 am

      There are so many things that could prevent your plants from thriving. The whitish color of the stems could have been a fungus that you brought home and introduced to your soil. I may be that your soil pH was too high or too low, too much chemical fertilizer, a mineral deficiency, etc. I don’t know where you live, but the best information will come from taking your plant to your local Agricultural Extension office to have a look at it. You should also bring a sample of your garden soil for testing. (Soil tests are FREE in NC from April through November.) The information you get back should help you prevent this trouble in the future. There may still be time to plant new tomatoes this season if you hurry! Kind regards,


  • Carol Brennan says:
    June 1, 2018 at 10:04 pm

    Hi Ellen,
    This is my first year of having a raised garden. My tomato plants have curled leaves on top. I did use horse manure and I’m worried the tomatoes are harmful to eat. I also have squash and zucchini’s and I’m worried they might be harmful too. I’m in the Raleigh area of NC and I’m wondering if this maybe due to a broadleaf herbicide. Can you put my mind at ease please. Thanks for any help, Carol.


    • admin says:
      June 3, 2018 at 12:10 pm

      Hello Carol,
      Thanks for your message. It is so sad about the horse manure. None of it is safe to use in your garden any more because the strong herbicides used on pastures do not break down when they go through the horse. The curled leaves on the tomatoes are usually thick and gnarled and the plant is almost always stunted. Tomato plants seem to be affected the worst. The fruit is probably safe enough to eat, if you actually get any, but Organic farmers lose their organic certification for 3 years if they get tainted manure.
      You might consider growing things in pots this year instead. Adding activated charcoal to your garden (available through companies that supply lawncare companies) or Bio-char may help clear the soil of toxins before you plant again next year.
      Best of luck to you!


  • Ted Pendlebury says:
    June 8, 2018 at 1:18 am

    I guess it’s possible that’s from herbicide, but I don’t think it’ll automatically dissipate after it composts. I have the same issue, but I used some well composted compost from a municipal source. Stems are hard and veined, leaves curling as seen in your photo. Hmmm, not sure I want to eat any of these tomatoes.


    • admin says:
      June 8, 2018 at 2:41 am

      Thanks for your comments. Too bad you got herbicide damage from compost! The herbicide will NOT dissipate with composting, not for at least 3 years anyway.
      Best wishes to you!


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