What Is Wrong With My Tomato Plant

If you’re asking “what is wrong with my tomato plant,” you’re not alone. It’s a common question for gardeners of all levels. Tomatoes can be a bit fussy, but most problems have clear signs and straightforward fixes. This guide will help you diagnose the issue and get your plant back on track.

Start by taking a close look at your plant. Check the leaves, stems, and fruit. Look for discoloration, spots, wilting, or strange growth. The location of the problem—old leaves, new growth, or fruit—is a big clue. Also, think about your recent weather and watering habits. These details are the first step to finding a solution.

This section covers the most common symptoms. Match what you see on your plant to the descriptions below to identify the likely culprit.

Yellowing Leaves

Yellow leaves are probably the top complaint. The pattern of yellowing tells you alot.

Lower, Older Leaves Turning Yellow: This often signals a nitrogen deficiency. The plant moves nitrogen to support new growth. A balanced fertilizer can help. It can also be a natural process of older leaves dying off.
Yellow Leaves with Green Veins: This is a classic sign of magnesium deficiency. Epsom salt (magnesium sulfate) dissolved in water and applied to the soil can correct this.
Overall Yellowing, Starting with New Growth: This could indicate overwatering, which causes root rot, or a lack of essential nutrients like iron.

Leaf Spots, Blights, and Fungi

Spots and lesions are usually caused by fungal or bacterial diseases, especially in humid weather.

Early Blight: Looks like dark, concentric rings on lower leaves, like a bullseye. Leaves eventually turn yellow and fall off.
Late Blight: More serious. Causes irregular greasy gray spots on leaves, with white fuzzy mold underneath in damp conditions. Stems get blackened areas.
Septoria Leaf Spot: Many small, dark brown spots with lighter centers appear on lower leaves. Leaves yellow and drop.

For all fungal issues, remove affected leaves immediately. Improve air flow, water at the soil level (not the leaves), and use a fungicide if needed. Rotate your crops each year.

Wilting Plants

A drooping tomato plant is a sad sight. The cause depends on the timing.

Wilting During the Day, Perking Up at Night: This is often just heat stress. The plant is losing water faster than it can absorb it. Provide shade during the hottest part of the day.
Wilting That Doesn’t Recover: This is serious. It could be Fusarium or Verticillium Wilt, soil-borne fungi that clog the plant’s vascular system. There is no cure; remove the plant. Next time, choose wilt-resistant varieties (marked with F, V, or VF on the tag).
Sudden, Severe Wilting: Check the base of the stem for holes or sawdust-like material. This could be a borer insect. Also, check if you’ve accidentally damaged the stem with garden tools.

Blossoms Falling Off or No Fruit

It’s frustrating when flowers appear but no tomatoes follow. This is called blossom drop.

The main cause is temperature stress. Night temperatures below 55°F (13°C) or day temperatures consistently above 90°F (32°C) can prevent pollination. Other causes include too much nitrogen fertilizer (which promotes leaves, not fruit) or extreme underwatering. Be patient; fruit will often set when weather improves.

Problems with the Fruit

Sometimes the plant looks healthy, but the fruit has issues.

Blossom End Rot: A dark, leathery spot on the bottom of the fruit. It’s caused by a calcium deficiency in the fruit, usually due to irregular watering (drought followed by a flood) that prevents calcium uptake. Maintain consistent soil moisture and avoid over-fertilizing with high-nitrogen feeds.
Cracking or Splitting: Caused by a sudden influx of water after a dry period, which makes the fruit expand to fast. Keep watering even, and choose crack-resistant varieties.
Catfacing (Misshapen, Scarred Fruit): Often caused by cool temperatures during flowering. It’s mainly cosmetic; the fruit is still edible.
Sunscald: Pale, white, or blistered patches on fruit exposed to direct, hot sun. Provide adequate leaf cover through proper pruning (but don’t over-prune).

Insect Pests

Tiny bugs can cause big problems. Inspect the undersides of leaves.

Aphids: Small, soft-bodied insects in green, black, or white clusters. They suck sap and excrete sticky “honeydew.” Blast them off with a strong jet of water or use insecticidal soap.
Tomato Hornworms: Large, green caterpillars that can strip a plant overnight. Hand-pick them off (they’re camouflaged well) or use a biological control like Bt (Bacillus thuringiensis).
Whiteflies: Tiny, white, moth-like insects that swarm when disturbed. They also secrete honeydew. Use yellow sticky traps and insecticidal soap.
Spider Mites: Tiny pests that cause stippling (tiny yellow dots) on leaves. Fine webbing may be visible. Increase humidity and spray with water or horticultural oil.

Quick-Step Diagnostic Checklist

Look at the Leaves: Yellow? Spotted? Curling? Wilting?
Examine the Stems: Any holes, lesions, or discoloration?
Check the Fruit: Any rot, spots, or cracks?
Inspect for Bugs: Look under leaves and along stems.
Review Your Care: Has watering been consistent? What’s the weather been like? Did you fertilize recently?

Prevention is the Best Medicine

Healthy plants resist problems better. Here’s how to set them up for success:

Choose Resistant Varieties: Look for letters like V, F, N, T on plant tags indicating disease resistance.
Water Deeply and Consistently: Water at the soil level, not the leaves. Aim for 1-2 inches per week. A soaker hose is ideal.
Provide Support and Space: Use cages or stakes for good air circulation. Don’t crowd plants.
Rotate Crops: Don’t plant tomatoes in the same spot for at least 3 years.
Mulch: A layer of straw or wood chips conserves moisture, suppresses weeds, and prevents soil-borne diseases from splashing onto leaves.

FAQ: Tomato Plant Problems

Why are the leaves on my tomato plant curling?
Leaf curl can be caused by high heat, drought stress, over-pruning, or a viral infection. Physiological leaf roll (upward curling) from environmental stress often doesn’t harm the fruit.

What causes tiny holes in tomato leaves?

This is often flea beetles or caterpillar damage. Inspect leaves closely, especially in the evening. Floating row covers can protect young plants.

Should I remove yellow leaves from my tomato plant?
Yes, carefully prune and discard any yellow or diseased leaves from the bottom of the plant. This improves air flow and redirects energy to healthy growth.

How often should you water tomato plants?
There’s no single schedule. Water when the top inch of soil feels dry. Deep, infrequent watering is better than daily light sprinkles. Container plants need water more often.

What is the best fertilizer for tomatoes?
Use a balanced fertilizer when planting. Switch to a fertilizer lower in nitrogen and higher in phosphorus (the middle number) when flowering begins to promote fruit set.

Figuring out what is wrong with your tomato plant takes a little detective work, but it’s a skill you’ll quickly develop. Start with the most obvious symptoms, check your plant care basics, and take action early. With these tips, you’ll be on your way to a healthier, more productive tomato harvest in no time.