Water deeply and consistently, not daily sprinkles
Tomatoes need steady moisture, not wet soil. Water at the base of the plant — not the leaves — and soak the ground until it is moist 6 to 8 inches down. Check the soil with your finger before watering; if it is still damp an inch below the surface, wait another day.
Most tomatoes need water every two to three days in warm weather, but this depends on your soil, rainfall, and temperature. Sandy soil dries faster than clay, so you may water more often. Mulch around the plant with 2 to 3 inches of straw or wood chips to hold moisture and keep roots cooler.
Inconsistent watering causes problems: too little leads to blossom end rot (dark spots on the bottom of the fruit), and too much can split ripe tomatoes or encourage fungal disease. Drip irrigation or soaker hoses work better than overhead sprinklers because they deliver water where it is needed and keep foliage dry.
Key Takeaways
- Water at the soil level, not the leaves, and soak deep enough that moisture reaches 6 to 8 inches down every two to three days in warm weather.
- Mulch the base of the plant with 2 to 3 inches of straw or wood chips to retain moisture and prevent soil-borne disease from splashing onto leaves.
- Prune suckers (shoots that grow between the main stem and branches) on indeterminate varieties to direct energy toward fruit rather than foliage.
- Support the plant with a cage, stake, or string as it grows so branches do not break under the weight of fruit.
- Remove the lowest leaves once the plant is established to improve air flow and reduce fungal disease.
Support the plant as it grows taller
Tomato branches become heavy as fruit develops, and unsupported plants break or sprawl across the ground. Install a support system early — when the plant is 6 to 12 inches tall — rather than trying to prop it up later.
A cage (the wire cylinder kind) works for compact determinate varieties and requires no tying. Drive it into the soil at planting time so you do not damage roots later. A stake (a 5- to 6-foot wooden or metal post) suits taller indeterminate varieties; tie the main stem loosely to the stake every 8 to 12 inches as it grows, using soft cloth strips or garden twine so the ties do not cut into the stem.
String trellising is common in commercial growing: tie a string to the base of the plant and to a horizontal wire or beam above, then gently wind the stem around the string as it grows. This method saves space and keeps fruit off the ground where it can rot or attract pests.
Prune suckers on indeterminate varieties to focus energy on fruit
Indeterminate tomatoes (the tall, vining kind that grow all season) produce suckers — small shoots that sprout between the main stem and branches. These shoots will grow into full branches if left alone, creating a dense plant that produces more leaves than fruit and traps moisture inside.
Pinch off suckers when they are small — 1 to 2 inches long — by snapping them off with your fingers or cutting them with pruning shears. Focus on the lower half of the plant first. You do not need to remove every sucker; removing the largest ones is enough to open up the plant and improve air flow.
Determinate varieties (bush types that stop growing at a set height) produce fewer suckers and do not need pruning. If you are unsure which type you have, check the seed packet or plant label.
Remove lower leaves to prevent fungal disease
Once the plant is 12 to 18 inches tall and has set its first fruit, remove the lowest 6 to 8 inches of leaves. These leaves are closest to the soil, where fungal spores live, and they are shaded by upper foliage so they do not photosynthesize well anyway.
Removing lower leaves improves air circulation around the base of the plant, which reduces the humidity that fungal diseases like early blight and septoria leaf spot need to spread. Cut or pinch off leaves cleanly; do not tear them, which leaves ragged wounds.
Continue removing lower leaves throughout the season as the plant grows taller. Stop removing leaves about four weeks before your first expected frost, because the plant needs foliage to ripen remaining fruit.
Watch for common pests and diseases
Hornworms are large green caterpillars that eat leaves and fruit. Check the plant weekly and remove them by hand, or spray with Bacillus thuringiensis (Bt), a natural bacterial insecticide that kills caterpillars but is safe for people and beneficial insects.
Early blight appears as brown spots with concentric rings on lower leaves, usually starting in mid-summer. Remove affected leaves and improve air flow by pruning. If the disease spreads, spray with a copper fungicide or sulfur dust every 7 to 10 days, following the label directions.
Blossom end rot shows as a dark, sunken spot on the bottom of the fruit and is caused by calcium deficiency linked to inconsistent watering. It cannot be cured once it appears, but consistent watering and mulch prevent it. Remove affected fruit so the plant can focus energy on healthy ones.
Whiteflies are tiny white insects on the undersides of leaves that weaken the plant by sucking sap. Spray the undersides of leaves with insecticidal soap or neem oil every 7 days until they are gone.
Fertilize every two to three weeks once fruit sets
Tomatoes are heavy feeders and need nutrients throughout the growing season. At planting time, mix compost or aged manure into the soil. Once the plant flowers and begins setting fruit, feed it every two to three weeks.
Use a balanced fertilizer (equal parts nitrogen, phosphorus, and potassium, like 10-10-10) or a tomato-specific fertilizer (higher in phosphorus and potassium to encourage fruiting). Follow the package directions for the amount; too much nitrogen produces leafy plants with few tomatoes.
Liquid fertilizers work faster than granular ones and are easier to explore without burning roots. Water the plant first, then explore the fertilizer, then water again to help it soak in.
Pinch off flowers in late summer to ripen existing fruit
Four to six weeks before your first expected frost, pinch off new flower clusters. The plant will not have time to ripen tomatoes from these flowers before cold weather arrives, so removing them directs the plant's energy toward ripening the fruit already on the vine.
You can also remove some of the upper foliage at this time to let more sunlight reach the fruit, but leave enough leaves to protect the fruit from sunscald (white or yellow patches from direct sun exposure).
Frequently Asked Questions
How often should I water tomatoes in hot weather?
In temperatures above 85°F, tomatoes may need water every day, especially in sandy soil or containers. Check the soil moisture with your finger before watering. If the top inch is dry, water deeply. Mulch helps reduce how often you need to water.
Can I use tap water on tomatoes?
Yes, tap water is fine for tomatoes. If your tap water is very high in chlorine, let it sit in a bucket overnight before using it, or water with rainwater collected in a barrel. Most municipal tap water is safe to use directly.
What does it mean if tomato leaves turn yellow?
Yellow leaves can mean nitrogen deficiency (fertilize), overwatering (let soil dry out slightly), or disease (remove affected leaves and improve air flow). Lower leaves naturally yellow and die as the plant grows; this is normal. Upper leaves turning yellow usually signals a problem.
Should I remove all the leaves from a tomato plant?
No. Remove only the lowest leaves (the bottom 6 to 8 inches) to improve air flow and reduce disease. The plant needs foliage to photosynthesize and produce energy for fruit. Removing too many leaves stresses the plant and can sunscald the fruit.
When should I stop watering tomatoes before harvest?
Keep watering until the plant dies or you pull it out. Consistent moisture right up to the end helps the final tomatoes ripen fully and prevents them from cracking. Only reduce watering if the soil stays soggy or if disease pressure is very high.