7 Common Tomato Problems and How to Fix Them This Season

I’ve been growing tomatoes for over a decade, and every season I learn something new—often the hard way. Last year, I walked out to my garden on a July morning to find half my prize Brandywines split open like little red mouths screaming for help. Another year, I lost a whole row of San Marzanos to a sneaky fungus I didn’t catch until it was too late. If you’ve ever stared at a wilting plant or a fruit with a black bottom, you know the frustration. But here’s the good news: most common tomato problems are fixable once you know what you’re looking at. In this guide, I’ll walk you through seven issues I’ve faced myself—and exactly how to fix them this season.

Why Your Tomato Plants Are Wilting (and What to Do)

Wilting is one of those symptoms that can mean two very different things: either your plant is thirsty, or it’s sick. I’ve made the mistake of overwatering a plant that actually had fusarium wilt, thinking I was helping. That just made things worse.

First, check the soil. If it’s bone-dry an inch down, your plant likely needs water. Tomatoes need about 1–2 inches of water per week, and consistent moisture is key. But if the soil is damp and the plant still wilts—especially if the lower leaves turn yellow first—you might be dealing with a soil-borne disease like fusarium or verticillium wilt. These fungi live in the soil and attack the plant’s vascular system. Once they’re in, there’s no cure. Your best bet is to remove the plant (don’t compost it) and rotate crops next year.

I once lost three plants to fusarium wilt in a row. It turned out I’d planted tomatoes in the same spot three years running. Now I rotate my nightshades (tomatoes, peppers, eggplants) on a four-year cycle. If you’re starting fresh, choose resistant varieties—look for “VF” or “VFN” on the label.

Quick fix checklist: Check soil moisture at root level. If dry, water deeply. If wet and wilting persists, suspect disease and remove the plant. Always water at the base, not overhead, to reduce disease spread.

Cracking and Splitting: The Real Reason Fruit Splits Open

That morning I found my Brandywines cracked—some had deep radial splits, others had concentric rings around the stem. It looked like a disaster, but the fix is simple: inconsistent watering.

Tomatoes crack when they take up water too fast after a dry spell. The inside swells faster than the skin can stretch. This is especially common after a heavy rain following a dry week. Mulching helps buffer those swings. I use a 2–3 inch layer of straw around my plants, which keeps the soil moisture more even. Also, water consistently—don’t let the soil go bone-dry then flood it.

If you see a big storm coming and your fruit is nearly ripe, pick it early. It’ll ripen on the counter just fine, and you’ll avoid the cracks. Cracked fruit is still edible—just cut away the damaged part—but it won’t store long, so eat it fast.

My rule of thumb: Never let the soil dry out completely for more than a day during fruit set and ripening. A drip irrigation system on a timer changed my game completely.

Blossom End Rot: Black Spots on the Bottom

Blossom end rot (BER) is probably the most alarming problem for new gardeners. You see a beautiful green tomato, flip it over, and there’s a black, leathery patch on the bottom. I remember my first year—I thought it was some alien fungus. It’s not a disease; it’s a physiological disorder caused by a calcium imbalance.

Calcium is needed for cell wall development, and when the plant can’t move enough calcium to the fruit fast enough, the cells at the blossom end collapse. The most common trigger? Inconsistent watering. When the soil goes from wet to dry, the plant can’t take up calcium properly, even if there’s plenty in the soil.

Here’s what I do now: I test my soil pH every spring (tomatoes like 6.2–6.8) and add lime if needed. I also use a calcium spray on the leaves weekly during fruit set, though it’s a band-aid—fixing the watering is the real solution. Mulch, water evenly, and don’t over-fertilize with high-nitrogen stuff, which can compete with calcium uptake.

Can you eat tomatoes with BER? Yes! Just cut off the black spot—it’s not harmful, just ugly. The rest of the fruit is fine.

Yellow Leaves and Stunted Growth: Nutrient Deficiencies vs. Disease

Yellow leaves are a classic tomato worry, and they can mean a few things. I once panicked over a whole row of plants turning pale at the bottom. Turned out it was just nitrogen deficiency—easy fix.

If the lower leaves turn yellow and the plant looks stunted, it’s often a lack of nitrogen. I give them a side-dressing of fish emulsion or a balanced organic fertilizer (like 5-5-5) and they green up in a week. If the yellowing happens between the leaf veins (the veins stay green), that’s magnesium deficiency. A tablespoon of Epsom salt dissolved in a gallon of water, sprayed on the leaves, does the trick.

But here’s the tricky part: early blight also starts as yellow spots on lower leaves, then turns into brown rings. The key difference is that blight spots have a target-like pattern. If you see that, remove the affected leaves immediately and improve air circulation—prune the lower branches and space plants at least 3 feet apart. I use a copper fungicide spray at the first sign.

My honest take: Don’t assume disease first. Check your watering and fertilizer schedule. More often than not, it’s a simple deficiency you can fix in a weekend.

Pests That Steal Your Harvest: Aphids, Hornworms, and Whiteflies

I’ll never forget the year I found a hornworm the size of my thumb munching a branch clean. They blend in perfectly with the stem. Now I scan my plants every morning with a cup of coffee—it’s become a ritual.

Aphids are tiny and cluster on new growth. They suck sap and excrete sticky honeydew that attracts sooty mold. A strong blast of water from the hose knocks them off, or I spray neem oil (mix 1 teaspoon per quart of water with a drop of dish soap). Whiteflies are similar—they swarm when you shake the plant. Sticky yellow traps help, and neem works.

Hornworms are the biggest threat. They can defoliate a plant in days. Hand-picking is the most effective—look for black droppings on leaves. I also plant dill and basil nearby, which attract beneficial wasps that prey on hornworms. If you see a hornworm with tiny white cocoons on its back, leave it—those are parasitic wasp eggs that will kill it and help control the population.

Organic pest control I swear by: Neem oil for soft-bodied bugs, hand-picking for caterpillars, and companion planting for prevention. It’s not 100% perfect, but it keeps my harvest intact without harsh chemicals.

Fungal Diseases: Late Blight, Septoria Leaf Spot, and Powdery Mildew

Fungal diseases are the silent killers in a tomato patch. Late blight is the one that caused the Irish Potato Famine—it turns leaves and stems into watery, brown mush, and it spreads fast. I lost an entire crop to it one humid August. Now I plant resistant varieties (like ‘Mountain Magic’) and apply a copper fungicide every 10 days if the weather is wet.

Septoria leaf spot starts as small circular spots with dark edges and light centers on lower leaves. It doesn’t kill the plant but weakens it. The fix: remove infected leaves, water at the base, and space plants for airflow. Powdery mildew looks like white powder on leaves—it thrives in high humidity. I use a baking soda spray (1 teaspoon per quart of water with a few drops of soap) as a preventative.

Crop rotation is your best defense. Don’t plant tomatoes in the same spot two years in a row. I rotate with beans or corn, which break the disease cycle. Also, never compost infected plant material—bag it and toss it.

Fruit Not Ripening? Blossom Drop? Temperature and Pollination Problems

Last summer we had a heatwave in June, and my tomato flowers just dropped off without setting fruit. I was furious—all that work for nothing. Turns out tomatoes stop setting fruit when night temperatures stay above 75°F or day temperatures exceed 95°F. The pollen becomes sterile.

What I do now: I use shade cloth (40% shade) over the plants during extreme heat, and I water deeply in the morning. For pollination, I gently shake the plants when they’re in flower to help the pollen move. You can also use an electric toothbrush to vibrate the flowers—it mimics the buzz of bees. For fruit that just won’t ripen on the vine (common in cool fall weather), I pick them and ripen them indoors in a paper bag with a banana—the ethylene gas does the job.

Heat-tolerant varieties save the day: I now grow ‘Heat Master’ and ‘Solar Fire’ in my garden for summer planting. They set fruit even when it’s hot.

Worth bookmarking before your next heatwave—this knowledge has saved my harvest more than once.

Practical Takeaway

Every tomato problem I’ve listed here comes down to a few core principles: consistent watering, good soil health, proper spacing, and a watchful eye. You don’t need to be a plant scientist—just pay attention and act fast. Start with the most common culprits (water and nutrients) before jumping to diseases. And remember, even experienced gardeners lose plants. The season isn’t over until the first frost. Keep growing.