What's wrong with our tomato plants? No one commented in the pest and disease section and we really need help. They are turning brown from the bottom up.

Oh dear! It looks like you might have some sort of blight going on. If so, with the plants so close together, it will spread very easily and quickly.

I've had marginal success stopping bacterial blight with a douse over the whole root system with a dilute hydrogen peroxide solution. Take the stuff you buy at the drug store, and dilute it 32:1 with water. (4oz. per gallon) You'll have to remove that landscape cloth to douse the whole root system of all the plants that are affected. You should use about a gallon of peroxide per plant. It may not help at this point, but it certainly won't hurt.

For future reference, I wouldn't put landscape cloth down under tomato plants except maybe temporarily while they're getting going in the spring time to warm the soil faster. Now, in hot weather it will be making the soil much hotter than it already is, and the roots not able to breathe either. Removing it from the entire bed, and putting down maybe some organic mulch like wood chips might help the whole situation, too.

It does look like early blight, which most of the time comes later in the season. I concur about the plant spacing. You need to have at least three feet between plants each direction. Air flow around the base is essential. It helps reduce conditions conducive to disease.

Mulching is a great idea and something is better than nothing. I have tried plastic mulch but went away from it a long time ago. Water will not pass through to the plant base. My mulch of choice is layers of newspaper and 6-8 inches of weed free straw. Keeps weeds down, watering at the base is possible, keeps the plant root zone cooler...all the things mulch is supposed to do.

Treating blights at your stage is difficult. Besides the peroxide, there are fungicides on the market that will reduce the spread and prevent more disease but not many cures out there. Prevention is key. Proper air flow is major. Also proper spacing so each plant receives good nutrient uptake. Crowded plants are stressed and are unable to fight off diseases. Do not overhead water and don't water in the evening or night so that the leaves are wet overnight. Fungus playground. Good sanitation, particularly in the off growing season is essential to keep the funguses and other diseases at bay. And a proper mulching program keeping the leaves and the soil apart helps since most blights and other foliage diseases are soil borne.

It is amazing, but by thinning the numbers of tomato plants you will not generally lose production. Healthy, non-stressed plants will produce more. What are the varieties you are growing? Some do better than others at fighting off disease.

Some ideas that may work for this year but something to think about.

Just to add to what they said remove all infected lower leaves and burn them ASAP

This eould benifit by more air circulation. Try some epsom salt water as well.

I feel your pain, @Kvent42 ! My tomatoes are always similarly affected -- the best defense I've found is to give them enough fertilizer that they kind of grow faster than the disease progression, at least for a while. And this year I grew some of my plants inside a 15x7' hoophouse, which has delayed the disease considerably.

Elaine, when would you suggest to apply the H2O2 drench -- before there is any disease apparent?

LOL -- these were some of my plants in October of 2014 (NOT caused by freezing)

Sandy you may want to do a few crop rotations before planting tomatoes in that spot again, but to get tomatoes until Oct is fantastic for zone 4b. To help in the future remove all infected leaves as they appear and try to keep water off the leaves as much as possible. Also mulch your plants so when it rains dirt isn't splashed up on the foliage.

Weedwhacker said:I feel your pain, @Kvent42 ! My tomatoes are always similarly affected -- the best defense I've found is to give them enough fertilizer that they kind of grow faster than the disease progression, at least for a while. And this year I grew some of my plants inside a 15x7' hoophouse, which has delayed the disease considerably.

Elaine, when would you suggest to apply the H2O2 drench -- before there is any disease apparent?

LOL -- these were some of my plants in October of 2014 (NOT caused by freezing)

Wow, sure is nothing left of those plants!!

Newyorkrita said:

Wow, sure is nothing left of those plants!!

I didn't want to be too hasty about pulling them out, Rita... you know, in case they started flowering again or something

Weedwhacker said:

I didn't want to be too hasty about pulling them out, Rita... you know, in case they started flowering again or something