Why are my tomato plants leaves turning brown?

John Barrett
by John Barrett
  10 answers
  • Bev Bev on Jul 29, 2017

    From looking at your photo, I see several culprits: the tomato cage is keeping too many of the plants branches together and they are not getting enough sun and the trapped humidity is making them rot. Use tall wooden stakes for tying up your plants and remove the lowest and fruitless branches as the plants grow. You also have too much other vegetatation, i.e. grasses, weeds, too close that is encouraging leaves to die. Trim off all of the lower leaves and dying leaves immediately and dispose of them--not in your compost pile but in your trash pick-up. You may have the onset of a virus that you don't want on your soil. Also, next year NEVER plant vegetale species in the same spot as the soil can harbor last year's problems. Your tomatoes need much more room to grow and more sunlight. Your ground looks damp---do not overwater! Tomatoes like hot, sunny areas in loam soil. Good Luck!

    • Delicia Ambrosino Delicia Ambrosino on Jul 30, 2017

      I agree with Bev. Tomato's need pruning for airflow for good health and good fruit production. Also, any branches that start growing in between 2 branches ...pinch out. Also, when cutting a diseased plant do NOT throw the clippings on the ground/etc and DO dip your cutter in 1 cap bleach to 1 gallon water before using on another plant. Your plant is diseased. If it progresses pick what tomato's you have and pull the plant. Then find an ORGANIC disease drench and spray that area. Many plant diseases can stay soil borne forever and normally what effects tomato's can effect other veggies as well, peppers for example. Next year consider getting a biodegradable weed barrier. It lets water and nutrients through but keeps weeds and grasses out. You'll still need to prune those tomato's. Also, do your homework on gardening. Youtube is great but has a ton of varying ways. STICK with the ones who you see using or doing the same or very similar methods. Good luck

  • Dim27361994 Dim27361994 on Jul 29, 2017

    Not Enough Water

  • Josie calcari Josie calcari on Jul 30, 2017

    Blight......use Daconil......it helps very much.

  • S S on Jul 30, 2017

    check for aphids. very small (pin head)and same color as plant stem.

  • Prairieflower Prairieflower on Jul 30, 2017

    it could be any of the things mentioned by the other home talkers but definitely would recommend a sunny spot and let the soil dry before watering and leaving plenty of space around them. Another thing I want to mention is that when you plant your tomatoes next year toss some crushed egg shell and an aspirin in the hole when you plant. It seems crazy but it has worked very well for me. The calcium and aspirin helps the plant get the fertilizer and nutrition from the soil and will keep from them having blossom rot. Another wise tale about tomatoes is if you whack them with a broom handle and break braches( don't go nuts) just like a hail storm they will produce a ton of tomatoes. We had baseball sized hail last year and I thought it killed them. Like just stems sticking out of the ground. It didn't I got 150lbs of tomatoes off 6 plants. It took me like a month to can them all. Hope this helps!

  • Dave McGarvey Dave McGarvey on Jul 30, 2017

    Too much water. We can't do anything about rain really, but never water your tomatoes, so that the leaves get wet. Prune off all the dead and spotted leaves and get rid of them. If you look at a healthy tomato leaf, you will notice that it is very rough and water doesn't run off them well, like it would on a smoother leaf like bell peppers or green or lima beans. This spring i watered my tomatoes twice and it rained twice and with a little pruning of the bottom 10 inches or so and I have the healthiest and best looking tomatoes I have ever had. Other years when we have gotten several rains, my tomatoes look like yours.

  • Gary Canada Gary Canada on Jul 30, 2017

    I agree with the previous posts, but there are a couple of issues that most people do not know. First, Tomato plants do need a lot of room, but it is better to use a welded wire fence about four to five feet tall, placed in a ring for support. His helps them to grow vertically without choking them. Pulling the suckers is very important as well. The biggest No-No that people do is water the leaves! Tomatoes HATE getting their leaves wet, it sends the tomato into shock every time they get wet. Yes, this means protect them from rain as well. Water them from the ground, and keep the leaves dry. It looks like the lower branches might have been scalded, a possibility. They look like they were frozen as well, but we can eliminate that since it is obviously growing season, and not the fall of the year. My average tomato is about the size of a softball, and all I use for fertilizer is worm castings. Think about the last post, the fuzzy leaves trap water causing issues. If you prevent the leaves from ever getting wet, and keep them watered well from the ground you will have more and larger tomatoes, earlier than any of your neighbors... I know I consistently beat my neighbors, they ask why, but refuse to do this one simple little thing. Think about it, when a plant goes into shock, they stop growing and producing until they recover. If your plants do not go into shock, they never stop growing, putting you ahead of everyone else. I have been growing tomatoes for over 25 years, and have never had a failed crop.

  • Janet Ridgeway Janet Ridgeway on Aug 01, 2017

    All of the above are good ideas, but my first thought was cats! Males like to scent & where the brown is showing is about the right height. Good Luck.

  • Deb K Deb K on May 19, 2023

    Hi John, hope this helps. Brown patches on leaves can be caused by magnesium deficiency, tomato blight or Fusarium wilt. Magnesium deficiency can be remedied by feeding every week with liquid tomato fertiliser. Blight and wilt are not treatable and in both cases the plants must be pulled up and burned or disposed of in the grey bin.