9 Common Problems with Growing Tomatoes in a Greenhouse and How to Fix Them

Tomato Plant Problems and Diseases

Armed with the information above, you can easily scan this list and narrow down the possible tomato plant disease caused by poor cultivation habits, bacteria, or fungi, plus learn tips on how to fix it. If a disease isn’t the issue, then insects may be the culprit. Check out our list of common tomato pests.

• It looks like the tomato plants are healthy, but as the tomatoes get riper, a black spot shows up on the bottom of them that looks bad. The black spots on tomatoes look leathery. It looks like the tomato inside is mealy when you try to cut off the patch to eat it.
• What causes it: Your plants aren’t getting enough calcium. Either the soil doesn’t have enough calcium or the pH is too low for the plant to take in the calcium that is there. Tomatoes need a soil pH around 6. 5 in order to grow properly. They can also take in calcium because of the pH level of the soil. Uneven watering habits also contribute to this problem. Hot, dry spells tend to exacerbate blossom end rot.
• What to do: Get a soil test from your local garden center or Cooperative Extension before you plant tomatoes. They can give you recommendations to adjust your soil. For calcium, you can add lime and gypsum, but you need to make sure you use the right amounts for your soil. Crushed eggshells can also be added to your compost pile to naturally raise the calcium level. When you add compost to the soil, A foliar spray with calcium chloride can keep tomatoes from getting blossom end rot in the middle of the season. Spray it on early in the morning or late at night; if you do it in the middle of the day, it will burn the leaves. Water plants every day at the same time to make sure they get an even amount of water.

• What it looks like: Your tomato plants get flowers, but the flowers fall off before the tomatoes grow.
• What causes it: Temperature fluctuations cause blossom drop. For tomatoes to keep their flowers, the temperature at night needs to be between 55 and 75 degrees F. If the temperatures fall outside this range, blossom drop occurs. Other things that can cause tomato blossoms to fall off are insect damage, not enough water, too much or too little nitrogen, and not enough pollination.
• What to do: You can’t change the weather, but you can make the rest of the plant strong by fertilizing tomatoes, planting milkweed and cosmos to attract pollinators, and killing insects with neem oil.

• How they look: Ripe tomatoes get cracks, which are usually in the shape of circles. It’s possible for bugs or birds to get into the fruit through the cracks and eat it.
• What causes them: Hot, rainy weather causes fruit crack. After a long dry spell, tomatoes are thirsty. After the first heavy rain, plants may quickly take in water, which makes the fruit swell and crack.
• How to deal with them: You can’t change the rain, but you can water tomatoes evenly while they’re growing. So, they don’t get so thirsty that they drink too much water during a heavy rainstorm.

• How it looks: The plants look good, and the fruit grows normally. As tomatoes ripen, yellow patches form on the red skin. Patches of yellow turn white and paper-thin, making the food look and taste bad.
• Why it happened: As the name suggests, the sun’s rays burned the tomato.
• What to do: Tomato cages, which are a wire support system that goes around the plants, give the best branch support and naturally shade the tomatoes as they grow. Sunscald usually happens on staked plants that have been pruned too hard, leaving many of the tomatoes open to the sun’s rays. Leaving some leaves and branches on the tree gives shade during the hottest parts of the day.

• It looks like you have some flowers but not many tomatoes. The tomatoes that are on the plant are small or don’t taste good.
• It happens because there is too much nitrogen in the soil, which makes plants grow lots of 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. Tomato flowers have both the male (stamens) and female (pistils) parts inside them, so they can pollinate themselves. Tomatoes are pollinated by wind, but if the plants are too close together, the wind can’t get to the flowers.
• What to do about it: Have your soil tested. Leave at least two feet of space between tomato plants when you plant them in the spring so that air can flow and help the plants get pollinated. If your plants are already in the garden, all you have to do to get the pollen from the stamens to the pistils is shake the flowering branches to make it look like wind.

• What it looks like: Catfacing makes tomatoes appear deformed. The blossom end is rippled, bumpy and lumpy.
• What causes it: Catfacing can happen to plants that were pollinated in the cool evenings, when the temperature is around 50 to 55 degrees F. Blossoms fall off when temperatures drop too low. But if the flower is pollinating before the petals fall off, some of the pollen stays on the tomato buds. This creates the lumps and bumps typical of catfacing.
• What to do: Plant tomatoes later in the season if you can. It should be warm enough for tomatoes to grow properly. Things like a “Wall of Water” can help keep temperatures high enough on cold nights to keep problems from happening because of the cold. Using black plastic on the soil can also help. The plastic gets hot during the day and gives the heat back to the plants at night. Use until the weather gets warmer and you don’t need it anymore.

• What it looks like: The leaves of fully grown tomato plants curl up all of a sudden, especially the older leaves near the bottom. Leaves roll up from the outside towards the center. Sometimes up to 75% of the plant is affected.
• What makes it happen: Leaf roll is often caused by high temperatures, wet soil, and too much pruning.
• What to do: Leaf roll is ugly, but it won’t stop tomatoes from growing, so you will still get tomatoes that you can eat from your plants. Don’t prune too much, and make sure the soil can drain away any extra water.

• What it looks like: The tomato plants are healthy and blooming as planned. There are ripe red tomatoes ready to be picked. When the tomato is cut in half, there are big empty spaces inside and not much fruit. Tomatoes may feel light when harvested. You might notice that the outside of the tomato looks sharp and square.
• What causes it: Under-fertilization, poor soil nutrition or inadequate pollination.
• Do something about it: Make sure you feed your tomato plants all season long. Every two weeks or once a month, you should use a balanced fertilizer like 10-10-10 on your plants. Tomatoes need fertilizer all through the growing season because they eat a lot. For gardeners, adding homemade compost and compost teas as top dressings often is a must.

• This is what it looks like: bacterial cankers start as yellow dots on ripening red tomatoes. They are often mistaken for cloudy spot disease. If you look closely at the spots (with a magnifying glass if you have one), you’ll see that each of the yellow spots has a dark, birds-eye edge around it. This is what distinguishes bacterial canker from cloudy spot disease.
• What causes it: A bacteria called Clavibacter michiganensis. The bacteria are found in nature, but infected plants or tools can bring them into the garden. It gets into the soil and rainwater splashes it on the plants. If the plant has an open wound, like one caused by an insect bite or a leaf that was cut off, the pest can get in.
• What to do: Get rid of the infected plants right away, and don’t plant tomatoes in that soil again for at least three years. To keep these and other diseases from taking over the soil, rotate your crops often. To keep the bacteria from spreading, don’t compost the dead plants. Instead, throw them away.

• To see it, a dark bull’s-eye circle shows up on the blossom end or bottom of the tomato as it ripens. The spot is sunken and mushy to the touch. Cut the tomato in half and look under it. There’s a black, mushy spot that looks like rot.
• What causes it: A fungus called Colletotrichum phomoides. The fungus grows best in warm, wet weather. It is usually spread by overhead irrigation, sprinklers hitting infected soil and splashing the fungus onto plants, and plants that are already infected to begin with.
• What you can do: Change the way you water your plants so that the water drips on their roots instead of their leaves. Pick tomatoes when they are ripe because tomatoes that are too ripe tend to get fungus more quickly than tomatoes that are still not ripe.

• What it looks like: first the older tomato leaves will have brown spots. Each spot starts to develop rings, like a target. Around the brown spots, the leaves turn yellow. Then the whole leaf turns brown and falls off. Eventually the plant may have few, if any, leaves.
• What causes it: A fungus called Alternaria solani. There is a fungus that can live in the soil all winter. If your plants have had problems like this in the past and you planted tomatoes in the same spot, it’s likely that they will have the same problem this year.
• How to fix it: crop rotation keeps the disease from spreading to new plants. If you plant peppers, tomatoes, or eggplants in the same spot every year, they could get early blight. A garden fungicide can treat infected plants.

• What it looks like: The lower leaves get yellow spots after the plants start to grow tomatoes. There are dark gray centers inside the yellow spots with dark edges. Black dots appear in the center of the spots. Foliage dies and falls off.
• What makes it happen: a fungus called Septoria lycopersici infects the leaves.
• What to do: Don’t water tomatoes from the top down, because the spray can push the spores that are growing on the leaves back into the soil, which keeps the disease going. Safer® Brand 3-in-1 Garden Spray is a spray that can be used to kill fungi.

• Things that happen: Your tomato plants look fine one minute, but then they start to wilt. The plant may be hurt on one side at first, but soon the whole thing is wilting. You water them, and the problem gets worse. Within a day or two, the plant is dead!.
• What causes it: A nasty fungus called Fusarium oxysporum f. sp. lycopersici that attacks the plant’s vascular system, which is like a person’s veins. The fungus breaks down the xylem tubes, which bring water and food from the roots to the leaves.
• How to deal with it: The best way to fight fusarium wilt is to attack it first. Change where you plant your crops so that you don’t always put tomatoes in the same spot in the garden. If you’ve lost tomatoes to wilting diseases in the past, buy varieties that don’t get it. The fungus can live in garden and lawn soils all winter.

• It looks like the lower leaves have yellow spots on them. The veins in the leaves turn brown as the spots get bigger. After the leaves turn brown, they fall off. The disease spreads up the stem until the plant can’t grow any longer.
• Verticilliurn albo-atrum, a fungus that lives in the soil, attacks the roots and moves up the xylem tubes with water. Then, it stops the leaves from getting the water and nutrients they need.
• There isn’t much you can do to treat Verticillium wilt once it has happened to plants. Change the plants you grow because the fungus can stay in the soil for a long time and even live with weeds like ragweed. The best way to stop Verticillium wilt is to plant varieties that don’t get wilt.

• What they look like: Tomatoes are mostly affected by viral diseases. Tolons may have black spots or strange stripes on them. Disease signs are not the same as the way some heirloom tomatoes look with their natural stripes.
• Why do they happen? A lot of these viruses spread when plants are under a lot of stress, like from heat, drought, or bad soil.
• Do something about them: If you’ve read all of these tomato problems and think your tomatoes might have a virus, spray neem oil on their plants. Tomato plants stay healthy when you take care of the soil and use organic fertilizer. This can help them naturally fight off viruses better.

• Powdery mildew is easy to spot on tomato plants because the leaves look like they were brushed with white powder. There may be white spots on the stem or leaves of the tomato. The fungi will turn your tomato leaves yellow and then brown if you let them grow.
• Why does it happen? Because greenhouses don’t let air flow and are very humid, powdery mildew on tomatoes is more common there than in an outdoor garden.
• What to do: A sulfur-based preventative spray is the best way to keep tomato plants from getting powdery mildew. Read this post to learn more about how to keep plants from getting powdery mildew and how to treat it if they do.

SOLVE TOMATO PROBLEMS WITH SAFER® BRAND

Before diving into the list, it’s important for you to correctly identify the problem or tomato plant disease. When trying to identify tomato plant diseases, use these steps:

• Figure out what part of the plant is hurt. Is it the tomato, the leaves, the stems, the flowers, or the roots?
• Write down the differences: What makes your tomato plant different from a healthy one? For example, a healthy tomato plant has medium-green leaves that are softly fuzzy. Write down if your plant’s leaves have brown or black spots, holes, chewed edges, or fuzzy mold growing on them before you read the list of problems.
• Look for bugs. What bugs do you see on your plants? If you don’t know what they are, take a picture and call your local Cooperative Extension agent. They can help you figure it out.

Now that you know this, it’s easy to look over this list and narrow down the possible tomato plant diseases that are caused by bad growing practices, bacteria, or fungi. You can also learn how to fix them. If a disease isn’t the issue, then insects may be the culprit. Check out our list of common tomato pests.

7 Mistakes to AVOID When Growing Tomatoes |Are You Guilty of These?|

FAQ

What are the disadvantages of growing tomatoes in a greenhouse?

Greenhouse Tomatoes are susceptible to many diseases caused by fungi, bacteria and viruses. They are also plagued by many abiotic problems caused from fertility and environmental problems.

Do tomatoes do well in a greenhouse?

Tomatoes can grow in pots, troughs, or greenhouse borders. – The containers should be deep enough and provide adequate soil for your tomato plants.

Should you take the bottom leaves off of tomato plants?

Getting Rid of Lower Leaves: It’s a good idea to get rid of a few lower leaves that have turned yellow or been bit off by a slug. Plants stay healthy because bugs and germs can’t eat the leaves that are falling off. It also helps air flow around the plants’ bases.

Why are my tomato plants dying in the greenhouse?

Possible causes include lack of water, fungal wilt diseases, tomato spotted wilt virus, walnut toxicity and stalk borers. Lack of Water.

Can a tomato plant die in a greenhouse?

The Problem with Tomatoes Grown in a Greenhouse: According to the University of Delaware, tomato plants can handle high temperatures for short periods of time. However, if they are exposed to temperatures above 90oF (32oC) during the day or 72oF (22oC) at night for several days or nights, the plants will lose their flowers and fruit. Why are my tomatoes dying in my greenhouse?.

Why do you need a greenhouse for tomato plants?

A greenhouse provides a natural barrier between your tomato plants and creepy-crawlies. You can limit diseases. A well-maintained greenhouse offers healthy circulation and consistent watering, which minimizes the conditions in which tomato blight and tomato funguses flourish. Q. What types of greenhouses are best for growing tomatoes?

Can Tomato plants grow in a greenhouse?

Tomato plants are one of the top plants that greenhouse growers choose to grow inside of a greenhouse. The warm and protected climate makes for a perfect tomato-growing environment. Unfortunately, tomato plants aren’t the only thing that thrive in a greenhouse. Tomato pests and diseases can get inside and threaten the health of your tomato crop.

Should you cram a tomato plant in a greenhouse?

It’s tempting to cram in more tomato plants to maximize limited greenhouse space. However, overcrowded tomatoes compete for light, water, and nutrients, stunting their growth. Follow spacing guidelines and allow at least 18 inches between plants. Prune regularly to improve light and air penetration to lower leaves. 6.

What should I look for in a tomato greenhouse?

Look for tomato varieties with good resistance to common greenhouse issues like blight, fusarium wilt, verticillium wilt, and viruses. There are a few key elements to take into account while setting up the perfect greenhouse for producing tomatoes:

What fungus affects tomato plants?

Stemphylium gray leaf spot is another common fungal disease that can affect your tomato plants. While cherry tomatoes and grape tomatoes are especially prone to this particular fungal disease, greenhouse plants are particularly desirable environments for this fungus to thrive.