8 Causes of Mealy, Mushy Tomatoes
Mealy, mushy tomatoes are no fun, no matter what stage of the ripening process. Get to the bottom of this issue with tomato grower Jerad Bryant as we look at the eight main reasons tomatoes get mushy. We’ll identify the issue behind your mealy tomatoes using the process of elimination.
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I’ll let you in on a gardening secret: every gardener picks a mealy tomato once and most of us don’t initially know the cause! This is a right of passage for all, as it helps us understand that a diligent eye is important. Looking closely at our harvests helps us find clues to novel garden discoveries.
A mushy tomato is no fun though, and will have you thinking you have a black thumb. Don’t worry, as this gross texture is correctable. Catch it early in your growing season and you’ll have gorgeously ripe tomatoes in a few days.
I once had mealy tomatoes because of infrequent watering, which led to a calcium deficiency. I simply watered more, and the issue fixed itself! By autumn, I was eating ripe heirloom tomatoes.
Here are 8 main causes of mealy, mushy tomatoes. Cross-reference them with your recent garden practices to see if they match. Correct each issue until your tomatoes are ripe, perfectly firm, and delicious.
Watering Infrequency
Water fluctuations stress your plants out! With too little water, tomatoes struggle to swell, forming cracks or crevices on their skin. But too much water causes the fruits swell over their normal size. They eventually split and decay quicker than non-split fruits.
Keep mushy tomatoes away by watering when the top layer of soil dries. Avoid watering too often or too little, and you’ll have plenty of perfect tomatoes with wonderful textures. This video details the best watering practices and a few other things we wish we knew when first growing this crop:
Blossom-End Rot
Blossom-end rot is a very common cause of mealy, mushy tomatoes. It typically results from a calcium deficiency or pH imbalance in your tomato plant. This happens for a few reasons. The most likely is infrequent watering. Calcium is water soluble, so more of it is available in wet soils than in dry ones. If your tomatoes experience drought after soggy soil, they may form blossom-end rot.
This condition manifests in brown, black, and mushy spots on the bottoms of tomatoes. They’ll slowly creep upwards as your tomato ripens, resulting in inedible fruits.
Before adding calcium fertilizer, see if your tomato’s soil is dry or wet. Add a timer to your watering system, or set a schedule to ensure consistent irrigation. If tomatoes still have blossom-end rot, consider adding a calcium and magnesium fertilizer, or “calmag.” Using a tomato-specific fertilizer like Espoma Liquid Tomato food will give you a fast-acting solution.
Early Harvest
If you harvest too early, the fruits might still ripen, but they’ll have a weird texture and bland flavor. During fall, you may have leftover unripe fruit on tomato vines. Most green tomatoes struggle to properly ripen if picked before they reach 40-60% ripeness. This half-ripe level is the “breaker stage.”
If you must pick early, like if there’s an early fall frost approaching, harvest to ripen indoors. Place them under bright light near a window in a warm spot in your kitchen. This encourages wholesome ripeness without mealiness or mushiness. Once they reach 90-100% ripeness, place them in the fridge for up to two weeks, or eat them fresh!
Late Harvest
Late harvests also cause significant ripening issues that lead to mealy tomatoes. When left to ripen too long on the vine, these fruits grow mushy as they start to rot. Bright red fruits attract fruit flies, birds, and small mammals. If over-ripening doesn’t cause mushiness, one of these critters might.
Try taking a garden walk once a day, especially from midsummer onwards, as tomatoes ripen quickly. It doesn’t have to be long, but a little walk helps you see ripening fruit. That way, you’ll catch them before they go too far. Sometimes it’s best to harvest at 50-80% ripeness to prevent over-ripening.
Fertilizer Imbalance
A few nutrients cause mushy fruits when they’re out of whack, like excess nitrogen, low calcium, or low potassium. Nutrient and water availability affect each other, especially in terms of calcium. Ensure that your tomato plants receive regular moisture before adding fertilizer.
The best way to know what your soil needs is with a soil test, although some deductive reasoning will help you determine what it needs, too. If leaves curl at the top of plants, and flowers drop before they form fruits, your plants could have too much nitrogen.
Calcium deficits cause blossom-end rot, leading to stressed plants. Potassium helps tomato plants grow flowers and fruits continuously. Fruits in the process of ripening can rot when missing this nutrient, and new leaves sprout with yellowing margins. If nutrients are at a deficit, apply a balanced, low-nitrogen fertilizer high in potassium, phosphorous, and calcium.
Tomato Variety
In some cases, you may never get away from mealy tomatoes! Certain varieties naturally ripen this way, making soft fruits. If you prefer juicy textures, these types might be right for you. Eat these varieties before they ripen fully to have less mushy texture, or try a different type with less juice next year.
Some famous varieties known for their occasional mushiness are ‘Cherokee Purple’ and ‘Brandywine.’ Although delicious, their texture quickly degrades when they go past peak ripeness. Harvest fruits before they excel above 60% ripeness, and let them continue indoors until they’re ready for slicing.
If you’d like to avoid mealy textures, try firm Roma-type varieties like ‘San Marzano.’ They grow fruits with thick flesh, perfect for sauces, canning, or slicing.
Pests
Some pests cause tomatoes to get mealy before they’re ready to eat. Ripe red fruits attract them, so avoid dealing with these critters by ripening indoors. Picking at the “breaker stage” extends your harvest window and reduces the risk of pest damage.
Tomato Fruitworm
This worm is the larvae form of a common moth. It tunnels into ripening tomatoes at their stems, as evident by a black hole in this region. When you slice into your tomato, tunnels, decay, and worm poop will be inside. This nasty caterpillar causes your tomato to become mushy, mealy, and rotten inside.
If you spot worms, dispose of them away from your garden. This ensures the larvae won’t form adult moths that lay eggs and repeat the destructive cycle. Harvesting at the breaker stage helps avoid this, as tomato fruitworms often target ripe fruit.
If you have particularly heavy infestations, look for biological predator bugs like native parasitic wasps. Release them for low-impact organic pest control.
Tomato Pinworm
This worm generally feeds on leaves, although in severe infestations, larvae spread to ripening fruits. You’ll notice small, round, black pinholes on the tops of the fruit. The pinworms burrow into fruits, eating the flesh inside. When full, they’ll drop to the soil to finish pupating. After a few weeks, they’ll emerge as winged moths to lay more eggs.
Inspect soil before you transplant it into your garden—these worms invade gardens through foreign soils, pots, and plants. If they’re already in your garden, practice sanitary measures by destroying infested plants at the end of your growing season. Consider burying infected plant material over a foot deep so adults can’t emerge, or dispose of them in your yard waste container.
Tobacco Budworm
A native species, tobacco budworms attack ripening crops throughout North America. They prefer tobacco and field crops but sometimes invade tomato plants when hungry. They, like the two pests above, are the larval stage of a moth’s development. They eat through tomato blossoms and fruits quickly, gaining energy to transform into moths.
Lure tobacco budworm moths with pheromone traps, then release the dead moths where birds or critters can eat them. Sprays with Bacillus thuringiensis bacteria in them, known as BT sprays, are extremely effective against tobacco budworm. Follow the label to use this pesticide correctly.
Diseases
Aside from blossom-end rot (not technically a disease), three other diseases cause mealy tomatoes. They often result from poor garden conditions, like low airflow or moisture. Ensure tomato plants have continuous access to wind and water throughout the growing season.
Anthracnose
This nasty tomato disease causes black, mushy, or mealy spots. It is spread by a fungus that infects ripening fruit.
Keep it at bay with these simple cultural controls:
- Water once the top of the soil dries.
- Ensure good airflow.
- Space tomato plants at least a foot apart.
- Use well-draining soil.
If anthracnose has spread to multiple other plants, an organic copper fungicide may help prevent the spread of the disease to healthy parts.
Bacterial Speck
This disease, like anthracnose, happens from high humidity, lots of moisture, and warm temperatures. It is also a fungus, and it infects tomato leaves and fruits. You’ll notice round brown scabs on infected fruits.
Keep bacterial specks at bay by creating the cultural conditions above and practicing crop rotation every few years. This ensures bacterial speck populations stay low as the pathogenic bacteria struggle to grow without their host plants.
Gray Wall
This odd disease is most often the result of a potassium deficiency. It’ll cause gray, necrotic areas inside fruits that grow over time. It manifests differently, sometimes on the fruit’s surface near its skin. Keep gray wall disease away by ensuring your plants receive consistent moisture and sufficient potassium during their lifetime.
