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10 Common Tomato Plant Problems and How To Fix Them

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10 Common Tomato Plant Problems and How To Fix Them

Here at Farmers’ Almanac, we get a lot of gardening questions. What tops the list are questions about tomato plants and how to fix certain tomato plant problems. We checked in with Safer® Brand organic gardening solutions and received some great advice from their organic gardening article archives. Take a look:

Common Tomato Plant Problems and How To Fix Them

If you’re one of the three million people who planted a home garden this year, you’re most likely growing tomatoes. Nine out of 10 gardeners grow tomatoes, and that number would be 10 out of 10 if the holdouts would taste a fresh garden tomato and compare it to a grocery store purchase. Nothing beats the taste of a fresh home-grown tomato!

Many gardeners who grow tomatoes, however, encounter growing problems. This list of common tomato plant problems and their solutions will help you identify an issue—whether it’s just starting or already full-blown — and show you how to correct it, so you can save your tomato plants and harvest yummy tomatoes this year.

1. Blossom End Rot

What it looks like: The tomato plants appear healthy, but as the tomatoes ripen, an ugly black patch appears on the bottoms. The black spots on tomatoes look leathery. When you try to cut off the patch to eat the tomato, the fruit inside looks mealy.
What causes it: Your plants aren’t getting enough calcium. There’s either not enough calcium in the soil, or the pH is too low for the plant to absorb the calcium available. Tomatoes need a soil pH around 6.5 in order to grow properly. This soil pH level also makes it possible for them to absorb calcium. Uneven watering habits also contribute to this problem. Hot, dry spells tend to exacerbate blossom end rot.
What to do about it: Before planting tomatoes in the spring, have your local garden center or Cooperative Extension conduct a soil test. Tell them you’ve had problems with blossom end rot in the past, and they will give you recommendations on the amendments to add to your soil. Lime and gypsum may be added for calcium, but they must be added in the proper amounts depending on your soil’s condition. That’s why a soil test is necessary. Adding crushed eggshells to your compost pile can also boost calcium naturally when you add compost to the soil. A foliar spray containing calcium chloride can prevent blossom end rot from developing on tomatoes mid-season. Apply it early in the morning or late in the day — if sprayed onto leaves midday, it can burn them. Water plants regularly at the same time daily to ensure even application of water.

2. Blossom Drop

What it looks like: Flowers appear on your tomato plants, but they fall off without tomatoes developing.
What causes it: Temperature fluctuations cause blossom drop. Tomatoes need night temperatures between 55 to 75 degrees F in order to retain their flowers. If the temperatures fall outside this range, blossom drop occurs. Other reasons for blossom drop on tomatoes are insect damage, lack of water, too much or too little nitrogen, and lack of pollination.
What to do about it: While you can’t change the weather, you can make sure the rest of the plant is strong by using fertilizer for tomatoes, drawing pollinators by planting milkweed and cosmos, and using neem oil insecticides.

3. Fruit Cracks

What they look like: Cracks appear on ripe tomatoes, usually in concentric circles. Sometimes insects use the cracks as an opportunity to eat the fruit, or birds attack cracked fruit.
What causes them: Hot, rainy weather causes fruit crack. After a long dry spell, tomatoes are thirsty. Plants may take up water rapidly after the first heavy rainfall, which swells the fruit and causes it to crack.
What to do about them: Although you can’t control the rain, you can water tomatoes evenly during the growing season. This prevents them from being so thirsty that they take up too much rainwater during a heavy downpour.

4. Sunscald

What it looks like: The plants look healthy, and the fruit develops normally. As tomatoes ripen, yellow patches form on the red skin. Yellow patches turn white and paper-thin, creating an unpleasant appearance and poor taste.
What causes it: As the name implies, the sun’s rays have actually scalded the tomato.
What to do about it: Tomato cages, or a wire support system that surrounds the plants, give the best branch support while shading the developing tomatoes naturally. Sunscald usually occurs on staked plants that have been too-vigorously pruned, exposing many of the tomatoes to the sun’s rays. Leaving some foliage and branches provides shade during the hottest part of the day.

5. Poor Fruit Set

What it looks like: You have some flowers but not many tomatoes. The tomatoes you do have on the plant are small or tasteless.
What causes it: Too much nitrogen in the soil encourages plenty of green leaves but not many flowers. If there aren’t enough flowers, there won’t be enough tomatoes. Another cause may be planting tomatoes too closely together. Tomatoes are self-pollinating, meaning that each flower contains both the male (stamens) and female (pistils) parts. Wind typically pollinates tomatoes, but if plants are too close together, the wind can’t reach the flowers.
What to do about it: Have your soil tested. If you’re planting tomatoes in the spring, leave at least two feet or more between plants so that good air circulation can help pollinate them. If your plants are already in the garden, you can simply shake the flowering branches to simulate wind and get the pollen from the stamens to the pistils.

6. Catfacing

What it looks like: Catfacing makes tomatoes appear deformed. The blossom end is rippled, bumpy and lumpy.
What causes it: Plants pollinated during cool evenings, when the temperatures hover around 50 to 55 degrees F, are subject to catfacing. Blossoms fall off when temperatures drop too low. However, if the flower is pollinating before the petals begin to drop off, some stick to the developing tomato. This creates the lumps and bumps typical of catfacing.
What to do about it: If possible, plant tomatoes a little later in the season. Make sure the weather has truly warmed up enough to support proper tomato development. Devices such as a “Wall of Water”—a circle of water-filled plastic tubes—raise temperatures near the tomato and help keep them high enough on cold nights to prevent cold-related problems. Using black-plastic spread on the soil can also help. As the plastic heats during the day, it releases the heat back towards the plants at night. Black plastic can be used as a temporary measure until the temperatures warm up enough that it’s no longer needed. Catfaced tomatoes are safe to eat; simply cut away the scarred areas.

Read more on learning to eat ugly produce!

7. Leaf Roll

What it looks like: Mature tomato plants suddenly curl their leaves, especially older leaves near the bottom. Leaves roll up from the outside towards the center. Sometimes up to 75% of the plant is affected.
What causes it: High temperatures, wet soil, and too much pruning often result in leaf roll.
What to do about it: Although it looks ugly, leaf roll won’t affect tomato development, so you will still get edible tomatoes from your plants. Avoid over-pruning and make sure the soil drains excess water away.

8. Puffiness

 

What it looks like: The tomato plants look fine, they bloom according to schedule, and ripe red tomatoes are ready for harvest. When the tomato is sliced, the interior has large, open spaces and not much fruit inside. Tomatoes may feel light when harvested. The exterior of the tomato may have an angular, square-sided look.
What causes it: Under-fertilization, poor soil nutrition or inadequate pollination.
What to do about it: Make sure you are feeding your tomato plants throughout the season. A balanced fertilizer such as a 10-10-10 should be fed biweekly or monthly. Tomatoes are heavy feeders and need fertilizer throughout the growing season. For gardeners, frequent top-dressings with homemade compost and compost teas are a must.

9. Early Blight

What it looks like: You’ll find brown spots on tomato leaves, starting with the older ones. Each spot starts to develop rings, like a target. Leaves turn yellow around the brown spots, then the entire leaf turns brown and falls off. Eventually the plant may have few, if any, leaves.
What causes it: A fungus called Alternaria solani. This fungus can live in the soil over the winter, so if your plants have had problems before like this, and you’ve planted tomatoes in the exact same spot, chances are good the same thing will happen to your plants this year.
What to do about it: Crop rotation prevents new plants from contracting the disease. Avoid planting tomatoes, eggplants or peppers in the same spot each year as these can all be infected with early blight. A garden fungicide can treat infected plants.

10. Viral Diseases

What they look like: Viral diseases mainly attack the tomatoes themselves. You might find black spots on tomatoes or weird stripes on them. Don’t confuse signs of disease for just how some heirloom tomatoes look with natural stripes.
What causes them: Many of these viruses spread when plants are stressed by heat, drought or poor soil.
What to do about them: If you’ve read through all of these tomato problems and think your tomatoes may be suffering from a viral disease, spray your tomato plants with neem oil. Good soil management and using organic fertilizer for tomatoes also helps keep your plants healthy, which can help them naturally resist viruses better.

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20 comments

1 elliot { 08.21.19 at 4:06 am }

enjoyed your info on what to watch out for when growing tomato’s

2 Geri Lowry { 07.14.19 at 7:43 pm }

gerilowry@aol.com: MY TOMATO PLANTS ARE PLANTED IN RAISED BEDS. THEY HAVE GROWN OVER 6′ , LOTS OF BLOSSOMS, BUT HAVE PRODUCED VERY FEW TOMATOES. THE VINES ARE SPINDLY, AND TALL. IVE GIVE THEM PLENTY OF WATER AND GOOD SUN AND PERIODIC GARDEN FOOD. WHAT’S MY PROBLEM?

3 Dianne { 07.11.19 at 7:42 am }

Usually our tomato plants grow tall with strong stalks. The last two years they grow short and stubby, bush like. Although we are getting growth the weight is dragging the stalks significantly downward. Yes we have planted in the same spot for many years but we always replace the soil at the top with 6 inches of planting soil, mulch and manure.

4 Darrel { 07.05.19 at 10:51 pm }

I have tomato plant some of them look just terrible, all curled up with leathery looking and feeling leaves. They are still green,for the most part. I’d forgotten about using milk to kill virus. Any other suggestions? Thanks

5 Susan Higgins { 06.24.19 at 9:30 am }

Hi Joe, this might be a good resource for you: https://learn.winecoolerdirect.com/common-grapevine-diseases/

6 Joe Jackson { 06.22.19 at 8:49 am }

I have a problem with my grapes that every year as soon as they start to ripen they get a little black spot and dry up and rot on the vine,

7 MikeA { 06.21.19 at 7:52 pm }

Regarding viral disease and fungal infections, and excellent and natural control (albeit quite expensive) is colloidal silver. Studies since the 1950s, and today, show that it is more effective than commercial fungicides and is excellent at controlling disease without killing beneficial bacteria. Because it’s so costly, I don’t use it as a preventative, but spray it when I am dealing with an attack of powdery mildew or blight. A more cost effective fungal control is whole milk (yes I said whole milk). Studies have shown it to be nearly as effective as colloidal silver for fungal infections and it’s affordable enough to use as a preventative (1:8 dilution with water and spray weekly in bright sun). The protein and bacteria in the milk kill fungus and mildew instantly. Since it tends to dry and cover leaves with a residue, I use it sparingly and only when my plants are under attack and I don’t have colloidal silver available.

8 John C { 03.01.19 at 11:17 am }

Use drywall for calcium. Rototil it in the soil along with nitrogen fertilizer
A sunny warm spot and moist works very well

9 Louise Mansolf { 06.22.18 at 7:59 pm }

A 5-3-2 dried chicken manure and Jack’s Blossom Booster 10-30-20 with a good weekly top dressing of a couple of handfuls of Fafard Planting Mix Soil makes for a great harvest. To keep strong plants from toppling, use good 6-8′ stakes assembled Tee-Pee fashion by cotton-string tying them at the top and then running one string down to the base of the plant, tying the base loosely and spiraling the plant around the string as it grows. Prune off low branches and secure bearing branches to the stakes as they develop. A little work but there is NOTHING like good tomatoes from your own garden!!!

10 Deb Rowlee { 06.08.18 at 7:56 am }

Borage planted with tomatoes for no or few hornworms.

11 suhiggins { 10.04.17 at 9:05 am }

Hi Barbara, For chemical-free options, hand picking is really the best, if you have the time. Inspect the plants daily. Some people dump them in a bowl of soapy water, but if you have backyard chickens, even better, as they love to eat them! You also want to till the soil at the beginning and end of each gardening season to destroy any overwintering larvae. Tilling is shown to kill larvae by 90%. Next season, try planting basil or dill. You’ve tried marigolds, and you say that didn’t work, but those two herbs might. Good luck!

12 Barbara Holliday { 10.02.17 at 8:07 am }

I have horn worms every year.tried marigolds,doesnt work.could u please advise what I can do.

13 Grandmacash { 09.01.17 at 11:14 am }

How can I control or prevent moldy leaves?

14 Lori { 08.31.17 at 3:12 pm }

I have some problems with viral desease, are those Tomatoes still safe to eat

15 Montana3802 { 08.31.17 at 7:21 am }

Great tips! Keep them coming.

16 Charles Garrison { 08.30.17 at 8:59 pm }

Thank you for your information on tomatoes. I have often wonder about problems fith tomatoes.

17 Darlene { 08.30.17 at 11:07 am }

Lots of good information, will use some of these ideas next year. Thanks

18 bigjohnt { 08.30.17 at 10:00 am }

I learned a lot, thanks!

19 BigJohn { 08.30.17 at 9:55 am }

I learned a lot.

20 Rickey Engle { 08.30.17 at 8:38 am }

thanks for all the tips,

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