What’s Wrong With My Tomato?

Get the scoop on common tomato issues—along with tips to make things right.

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Photo By: Image courtesy of Burpee

Photo By: Photo by Julie A. Martens

Photo By: Photo by Julie A. Martens

Photo By: Photo by Julie A. Martens

Photo By: Photo by Julie A. Martens

Photo By: Photo by Julie A. Martens

Photo By: Image courtesy of Gardeners.com

Photo By: Photo by Julie A. Martens

Photo By: Photo by Julie A. Martens

Photo By: Photo by Julie A. Martens

Picture-Perfect Tomatoes

Sun-ripened tomatoes easily earn their keep in even the smallest garden patch. But growing the perfect tomato can prove somewhat elusive. Flip through our gallery to diagnose your tomato problems—and discover strategies to set your world of vine-ripened flavor right again.

Blossom End Rot on Tomatoes

Those dark, sunken spots on the bottom of tomatoes are blossom end rot. It’s so common that in tomato circles they call it BER for short. It’s not a disease but a symptom of calcium deficiency. It occurs due to uneven watering (wet-dry cycles in soil), too-high nitrogen or root damage. You can eat tomatoes with BER—just cut the bottoms off. For a quick fix, treat plants with a calcium spray for BER. Keep soil consistently moist; using mulch helps. Test soil when tomato harvest ends. Amend as needed.

Tomato Flowers Drop

When tomato plants look healthy and flowers appear but drop without setting fruit, it’s usually not your fault. Blame this one on the weather. When day temperatures linger around 85°F to 90°F and nights stay above 75°F, tomato flower pollen becomes unviable. Once the hot spell passes, flower pollination will resume and tomatoes will form. Until then, keep plants well-watered and fertilized, so they’re ready to jump back into production. In regions where summer sizzles, grow heat-tolerant varieties, like ‘Solar Flare’, ‘Summer Set’, ‘Heatmaster’, or ‘Phoenix’.

Cracked Tomatoes

A cracked tomato means that while fruit was ripening, the water supply was uneven. A heavy downpour that soaks soil can result in roots sending huge amounts of water to ripening tomatoes—so much that they pop their skins. Cracked fruit is edible, but the cracks are more susceptible to mold. Eat ripe, cracked tomatoes before ones with smooth skins. 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.

Holes in Tomatoes

Small holes in tomatoes are usually caused by slugs. The problem is, once slugs open a hole, the tomato weeps juice, and soon other critters join the party, like pill bugs, fruit flies and wasps. The wound in the fruit also invites early decay and mold. Slugs attack low-hanging fruit first, but they also slime their way up tomato vines and supports. Research slug treatments and adopt several strategies to deal with them. When tomato season is done, before frost, continue to use slug treatments to kill adult slugs before they lay eggs.

Half-Eaten Tomatoes

If you’re discovering half-eaten tomatoes or ones with bite marks, you’re likely dealing with squirrels or chipmunks. These critters are notorious for clambering onto plants and taking a small bite out of fruits. Usually they’re after the water in the tomatoes, which is why they don’t eat the whole thing (although sometimes they do). A pet dog or cat does the best job of keeping these varmints away from your produce. Some gardeners distract the critters with treats set out just for them—in a remote corner of the yard. Check out the next photo for another idea to save your harvest.

Protect Tomatoes

Protect ripening fruit by swaddling it with plastic bird netting. This treatment keeps nibbling rodents (squirrels, chipmunks, mice) at bay, along with birds and wood turtles, who love to snack on low-hanging fruit. Cut small pieces of netting and wrap it around coloring fruits. Store netting pieces in the garden clipped to tomato supports.

Tomato Hornworm

Finding holes in leaves and missing leaves? You likely have a tomato hornworm at work. These large green worms can gobble a mature tomato plant almost overnight. The worms hide under leaves during the daytime. Get rid of them by visiting your tomato patch at night, when they come out to feed. Knock worms into a container of soapy water. If you see a worm with white tic tac-looking things sticking out of it, leave it alone. It’s been attacked by a parasitic wasp, and it’s on a death march. You want those white eggs to hatch and release more wasps into your tomato patch.

Tomato Early Blight

Dark spots on leaves with concentric rings followed by yellowing between spots is a sign of early blight, a tomato disease caused by a fungus. It occurs on lower leaves first; spots can also appear on stems. Control this blight by spraying plants with fungicide. Remove all fallen leaves and destroy them; do not add them to your compost. To prevent disease spread, avoid getting water on leaves and don’t work with plants when they’re wet. Early blight is contagious and winters over on plant debris. Destroy—do not compost—infected plants at the end of the season.

All Leaves, No Fruit

When your tomato plants are all leaves and no flowers, there’s likely too much nitrogen in the soil. Nitrogen fuels leafy growth, and when it’s abundant, your plants will have lush growth with dark green leaves. Your soil likely lacks phosphorus, which helps trigger flowering and fruit formation. Tomatoes are heavy feeders and benefit from receiving specialized tomato fertilizer, which is usually higher in phosphorous (the middle number on the fertilizer bag). It might read something like 2-3-1.

Tomato Late Blight

Late blight is another fungus disease on tomatoes, and it appears as water-soaked spots on leaves, fruits and stems. It’s a death sentence once it attacks a plant and usually spreads quickly to other plants. Track the disease spread by region online, and start treating your plants with fungicide when it occurs in your area. Destroy infected leaves and plants; do not compost them. To help prevent the disease, space tomato plants so they have good air circulation and avoid overhead watering.

Squirrels Might Be the Problem

If squirrels are the reason your plump, juicy tomatoes are now missing bits and pieces, you may be contending with pesky critters in the garden.