Troubleshooting Top 10 Tomato Problems

Tomato Pests and Diseases

June 9, 2020

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What is wrong with my tomatoes? What are common tomato diseases? Why are the leaves on my tomato plants dying? In the article (with video demo), we discuss the top 10 tomato problems—how to prevent issues now and also how to fix issues affecting tomato plants.

Aphids and Whitefly 

What is it? Aphids and whiteflies are tiny sap-sucking insects that can appear on plants in large numbers. Some types transmit plant diseases.

Solutions: Blast off small infestations with a jet of water, or spray plants (including leaf undersides) with a soapy water solution. Plant flowers, for instance marigolds, close to your tomatoes. These will help attract aphid and whitefly predators such as ladybugs and hoverflies. If necessary you can buy these predators to introduce into enclosed environments such as a greenhouse or hoop house.

Spider Mites 

What is it?  Spider mites are tiny mites that thrive in warm, dry conditions. They can quickly weaken plants. Keep an eye out for their faint webs. Take a closer look and you might see the tiny, usually red, mites.

Solutions: To avoid problems, don’t let your tomatoes dry out. If spider mites do attack, spray the plant all over with a fine mist of water. Drape the plant with a row cover for a few days to create the shady, humid conditions that the mites dislike.

Tomato Hornworm 

What is it? The tomato hornworm is a caterpillar that chews holes in tomato fruits.

Solutions: Check your plants regularly for signs of damage, and remove and destroy any hornworms you find. You may find hornworms with little white cocoons on them. This is great news, and they belong to the larvae of braconid wasps, which feed on hornworms and help bring them under control.

See our Tomato Hornworm page for more tips.

tomato-hornworm-braconid-wasps-2x.jpg
Image: Tomato Hornworm with helpful braconid wasps.

Late Blight 

What is it? Blight is a fatal plant disease that occurs during spells of warm, wet weather. Brown blotches show first on tomato leaves and stems, then the fruits. Eventually, the plant will wilt and collapse. Late blight also affects potatoes, which are related to tomatoes.

Solutions: Remove and destroy blight-infected plants as soon as you see signs of the disease. If your plants have suffered from blight in the past, try growing them under cover if possible – it’s rarely a problem with indoor tomatoes. When watering, take care to avoid splashing the leaves. It’s worth looking out for varieties described as ‘blight resistant’.

Learn more about avoiding blight with the right tomato.

Blossom End Rot

What is it? Blossom end rot causes sunken black patches at the blossom end of tomato fruits. It is a common disease caused by dry soil conditions which results in a shortage of calcium in the plants. Plants in containers are particularly susceptible. This is caused by uneven watering (wet-dry cycles in soil) and also too much nitrogen.

Solutions: Never let your soil dry out. Keep soil consistently moist; using mulch helps. For a quick fix, treat plants with a calcium spray. Feed your tomatoes regularly with a liquid tomato fertilizer. Test soil when tomato harvest ends. Amend soil as needed.

You can eat tomatoes Blossom End Rot—just cut the bottoms off.  Learn more about Blossom End Rot.

blossom-rot_full_width.jpg
Image: Blossom End-Rot. See all the examples of tomato problems in the video demonstration.

Split or Cracked Tomatoes

What is it? Tomato fruits split when they have been kept too dry, and then are watered heavily while the tomato is ripening. This causes the fruits to swell faster than the skins surrounding them.  This could also happen because a heavy downpour soaks the soil, sending so much water to the tomato roots that they pop out of their skin!

Solutions: Keep your soil evenly moist. Prevent the condition by mulching soil and watering tomatoes deeply twice a week, instead of giving plants a little water every day. When heavy rainfall is in the forecast, pick tomatoes that are almost fully colored. Cracked fruit is edible, but the cracks are more susceptible to mold. Eat ripe, cracked tomatoes before ones with smooth skins.

Magnesium Deficiency 

What is it? Magnesium deficiency is the most common mineral deficiency in tomatoes. It often occurs as a result of high potassium levels.

Solutions: Spray a solution of Epsom salts directly onto the leaves, then start using a tomato fertilizer that contains a higher proportion of magnesium.

Wilted, Yellow Leaves

What is it? Tomato plants and leaves can wilt when the soil is either too wet or too dry. Too wet and the roots literally drown, while very dry soil won’t supply plants with all the moisture they need. Tomato plants may develop yellow leaves as well as looking wilted.

Solutions: Pay close attention to watering. It’s important not to underwater or overwater tomato plants. Water generously when the weather is dry, or set up an irrigation system on a timer if you can’t be around to water by hand. Mature plants with lots of foliage may need watering twice a day. Make sure containers have generous drainage holes in the base so the excess water can drain out, and raise them up onto pot feet if water doesn’t drain away easily.

Tomato Flowers Drop

If you see the flowers dropping, the weather may be too hot. If temperatures are consistently up to 85 F to 90 F (or above) and nights stay above 75 F, tomato flower pollen becomes unviable. Until the hot spell passes, keep plants well-watered and fertilized. Another option is to grow heat-tolerant varieties, like ‘Heatmaster,’ ‘Homestead,’ ‘Solar Fire,’ and ‘Summer Set.’

Poor Fruit Set

What is it? Poor fruit set, when flowers fail to produce fruits, has a variety of causes such as poor pollination, too much heat, poor nutrition, and very dry or very humid air.

Solutions: Open greenhouse and hoop house doors every day (weather permitting) to ventilate and to allow access for pollinating insects such as bees. Pollination can be enhanced by tapping on supports to dislodge the pollen, or gently twiddle the flowers between your fingers. If your climate’s very dry, raise the humidity around plants with regular watering. And make sure to feed your plants regularly with a store-bought tomato fertilizer or a homemade high-potassium liquid fertilizer such as comfrey tea.

Holes in Tomatoes

This is not a common issue, but we have had questions about small holes in tomatoes. This is caused by slugs because your fruit may be on the ground or handing low. They can also crawl up tomato vines and support so keep an eye on your tomatoes and use slug treatments to kill adult slugs before they lay eggs. You don’t want holes in the tomatoes because it opens up wounds and entry points for many other bugs and diseases.

Half-Eaten Tomatoes

If your tomatoes are partially eaten, you have a critter! Often, we’re talking about squirrels or chipmunks and they’re often after the water in the fruit. You could wrap your tomoatoes in plastic bird netting, clipped to tomato supports.You could also provide a water bowl or bird bath to ensure the wildlife gets its water elsewhere. 

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Reader Comments

Leave a Comment

Tomatoes

My plants have good tomatoes just not as many as id like and my plants look like sticks not sure what im doing wrong

little holes in bottom leaves

What to do? They are in pots.

little holes

The Editors's picture

This could be Septoria leaf spot. Do not water the leaves (water the soil) and keep water from splashing on them. 

Tomatoe leaves turning black

I have cherry tomatoes plant growing in my greenhouse , and the leaves are turning black, the soil is always moist so why are they turning black?

black leaves

The Editors's picture

Very few plants thrive in soil that is always moist, so that may be part of the problem. You may be drowning the plant. It could be bacterial spot, which is prevalent during wet seasons (you see the connection?). It could be a blight, which is a soil-based fungi, but it’s more likely water related. Water less often, e.g., when the soil is dry, and see what happens. Impossible to know if the plants will survive.

Something is eating the ends of the tomato plants.

Something is eating the ends off branches of my tomato plants. It may be the same "thing" that is "rooting" into some of my herbs and eating them, like my basil, and oregano. So, what ideas do you have? Is this a groundhog or rabbit making pasta? If so what do I do to stop it?

critter caper?

The Editors's picture

We can not be absolutely certain but it sounds like a four-legged visitor is grazing in your garden. It could be bunnies or a groundhog/woodchuck or something else (can’t say, not knowing your surroundings). Is your garden fenced?? That might be your first step (against bunnies; groundhogs abide no boundaries).

Egg Shells & Epsom Salt

I'm 74 yrs old and have grown a garden every year since I was 14. I always put 1 tsp of Epsom Salt in the bottom of a deep hole, mix it into the surrounding soil, cover it with 1" of soil, sprinkle a handful of crushed egg shells inside the hole, then plant a tomato plant as deep as it will go in the hole. I then sprinkle a lot of crushed egg shells on top of the ground around the plant - this keeps all the cutworms/grubworms away from the stem on the plant as they will not crawl over the sharp egg shells. The Epsom Salt gives each plant the amount of Magnesium it needs and the eggshells give it all the calcium it needs throughout the growing season. I have never had any problem with any diseases and since I plant Marigolds among the tomato plants, I have never had any insect/bug problem either.

epsom salt and eggshells

The Editors's picture

We’re with you on this recipe! Thanks for sharing it with other growers. (Listen up, folks, to this voice of experience!)

Calcium

Wondering if sprinkling eggshells help with low calcium? I would rather use something natural than a store-bought mixture.

egg shells for calcium

The Editors's picture

Egg shells will add calcium but relatively slowly as they break down.

Blossom End Rot

I used to spray the fruit with calcium at the first sign of it.....then I got smart. One capsule of Calcium Citrate in the hole when planted acts all season long. Haven't had the problem since I started doing this. The Calcium Citrate is the same caps that people take as a supplement. It's available in retail stores and on line.

Tomato plants are tall but not much foliage

My tomato plants are tall but do not have much foliage.

too tall, few leaves

The Editors's picture

This sounds like too much nitrogen, which causes quick, leggy growth. Do a soil test and check the results. 

Half eaten tomatoes

Have same problem. Set-up game cameras to find out what's up in my north garden. Groundhogs and rabbits, those critters were burrowing under fencing and gorging on the low hanging veggies. Blood meal spread along fence and watered to let the blood meal soak into ground seems to work.

Half Eaten Tomatoes

Hi, I didn't put a fence around my in ground garden this year and so far all summer it's been great but now I'm finding the ripening fruits that are almost ready to pick half eaten. What is eating them and how do I stop it? Also my tomato plants are all very healthy and extremely tall but yellow and spotted mixed with brown fried up leaves at the base of each plant. What is the cause and how can I fix it?

Tomatoes

We have beautiful plants but no blossoms. How can we fix this. Thank you

Tomato plants without flowers

The Editors's picture

Often, when tomato plants are lush without blossoms, your soil may have too much nitrogen fertilizer. First, cease any nitrogen-rich fertilizers, including compost and manure. You could also balance it out by applying a potassium-rich fertilizer such as sea kelp. 

tomatoes

My tomatoes look fine but they are watery and tasteless. What am I doing wrong?

Too much water late in the

Robin Sweetser's picture

Too much water late in the season will make your tomatoes juicy but dilutes the flavor. They need a lot of sun to develop sweetness so if your plants are in a shady location, next year try a sunnier spot. It is hard to control the amount of rainfall your plants are getting but if you hand water or irrigate cut back the watering as the fruits begin to ripen.

Tomatoes

What about early blight? You never mentioned it. I have a real problem with that.

help for early blight

The Editors's picture

Our info on blight is on other pages, as it happens. See here if this sounds like your crop: https://www.almanac.com/blog/gardening-blog/avoid-blight-right-tomato

On our tomato page, https://www.almanac.com/plant/tomatoes, you can find questions and comments about early blight, too: For example, one reader’s problem sounded like early blight, typical of very hot weather, or a wilt, which can result from over/under watering. Remove all diseased plant tissue from the ground. Practice crop rotation, or if you grow only tomatoes, do not plant in the same place each year. Space plants farther apart (how much depends on the expected size of the plant, its growth habit). Avoid overhead watering. Fruit might turn red on these plants. If threatened with frost, remove and ripen indoors.

We hope this helps.

Tomatoes not getting ripe

What if they aren't getting ripe? To much foliage or maybe to much nitrogen?

tomatoes not ripe...

The Editors's picture

You may have a problem with nitrogen, but what has the weather been?? We are hearing from a lot of folks with the same problem—tomatoes won’t turn red—in areas that have had a relatively cool, wet summer, like us here in New Hampshire. And we’re blaming the weather. Tomatoes like it to be hot and dry. Hang on, they might ripen yet.

If they do not, lookey here for ways to turn them red or cook up green tomatoes: https://www.almanac.com/search/site/green%20tomato

Broken branch

Sorry for the subject change, this is new to me I have 3 tomato plants outside in very large pots that have grown to 7 feet. We just had a bad storm. The top half of a plant broke off . Can it be salvaged....the broken stem that is? It has 6 tomatoes on it that arent ready yet.

broken branches

This sounds crazy but it works. Do you have a place that is out of the weather where you can take the branches and hang them upside down and leave them until the fruit ripens? we had a friend do this and it works

Broken Branch

I had a plant that my husband accidentally hit with the weed eater and broke the stem. I took and used 2 sticks as a splint and fixed the pieces back together and use some medical tape to wrap it with and believe it or not, the plant mended itself and the tomatoes did just fine.

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