Water tomato plants deeply and regularly, but let the soil dry slightly between waterings
Tomato plants need consistent moisture, but not soggy soil. Water at the base of the plant — not the leaves — to reduce disease. Aim for about 1 to 2 inches of water per week, either from rain or from you. In hot weather or sandy soil, you may need to water more often. In cool weather or heavy clay, you may need less.
The best way to know if your plant needs water is to push your finger 2 inches into the soil near the stem. If it feels dry, water. If it still feels moist, wait another day or two. Inconsistent watering — especially letting the plant dry out and then soaking it — causes problems like blossom end rot (dark spots on the fruit) and fruit cracking.
Water early in the morning if you can. This gives the foliage time to dry and reduces fungal disease. If you water in the evening, the leaves stay wet overnight, which invites mildew and early blight.
Key Takeaways
- Water at the soil level, not the leaves, and aim for 1 to 2 inches per week depending on weather and soil type.
- Feed tomato plants every 2 to 3 weeks with a balanced fertilizer once they start flowering, or use a slow-release fertilizer at planting time.
- Prune suckers (shoots that grow between the main stem and branches) on indeterminate varieties to direct energy into fruit, but leave them on determinate types.
- Support the plant with a cage, stake, or string as it grows to keep fruit off the ground and improve air circulation.
- Remove lower leaves once the plant is established to reduce disease pressure from soil-borne fungi.
Feed tomato plants with nitrogen early, then switch to phosphorus and potassium when flowers appear
Young tomato plants need nitrogen to build strong stems and leaves. Once the plant starts flowering, it needs more phosphorus and potassium to produce fruit. A balanced fertilizer like 10-10-10 works for the early stage. Once flowers appear, switch to something like 5-10-10 or 5-20-20.
If you mixed compost or aged manure into the soil before planting, you may not need to feed for the first 3 to 4 weeks. After that, feed every 2 to 3 weeks. Slow-release fertilizers (pellets that break down over time) are simpler — you add them at planting and they feed the plant all season. Liquid fertilizers work faster but need to be applied more often.
Too much nitrogen causes the plant to grow lots of leaves but few flowers. Too little phosphorus and potassium means small fruit or no fruit at all. If you see yellowing leaves on an otherwise healthy plant, that can signal a nutrient problem — a soil test from your local extension office can tell you what is missing.
Support the plant with a cage, stake, or string to keep it upright and improve air flow
Tomato plants get heavy as they grow, and the weight of the fruit can break branches or tip the whole plant over. A cage, stake, or string keeps the plant upright, keeps fruit off the ground (where it rots or gets eaten by pests), and lets air circulate around the leaves (which prevents disease).
A cage works well for determinate varieties (bush types that stop growing at a set height). Push it into the ground at planting time, before the plant is large. A stake works for any variety — drive it 12 inches into the ground and tie the main stem to it loosely with cloth strips or soft ties as the plant grows. String or twine works too: tie one end to a stake or overhead support and loop it around the stem every 8 to 12 inches as the plant grows taller.
Whatever you use, install it early. Trying to cage or stake a plant that is already 3 feet tall and heavy with fruit damages roots and branches.
Prune suckers on indeterminate varieties to focus energy on fruit production
A sucker is a shoot that grows in the angle between the main stem and a branch. On indeterminate varieties (plants that keep growing all season), removing these suckers directs the plant's energy into making fruit instead of more leaves and stems. On determinate varieties (bush types), leave the suckers alone — they are part of the plant's natural shape.
Pinch off suckers when they are small and tender, ideally less than 2 inches long. Use your fingers or a clean knife. Do this every week or two during the growing season. If you wait until they are thick and woody, removing them wounds the plant and wastes energy.
Stop pruning suckers about 4 weeks before your first expected frost. At that point, the plant should focus on ripening the fruit it already has, not making new growth.
Remove lower leaves once the plant is 12 inches tall to reduce disease from soil splash
Soil-borne fungi like early blight and septoria leaf spot live in the soil and splash onto the lowest leaves when you water or it rains. Removing leaves that are within 6 to 12 inches of the ground stops the spores from reaching them in the first place.
Start removing lower leaves once the plant is established and at least 12 inches tall. Remove only a few leaves at a time — never strip the plant bare. Do this gradually over several weeks as the plant grows. Stop removing leaves by mid-summer so the plant has enough foliage to feed itself and protect the fruit from sunscald.
If you see spots or yellowing on any leaf, remove that leaf as soon as you notice it. Dispose of it in the trash, not the compost pile, so the disease does not spread.
Watch for pests and diseases, and act early when you spot them
Common tomato pests include hornworms (large green caterpillars), whiteflies, and spider mites. Common diseases include early blight (brown spots with rings), septoria leaf spot (small circular spots), and powdery mildew (white coating on leaves). Early action stops small problems from becoming big ones.
Check the undersides of leaves once a week. Look for discolored spots, holes, sticky residue, or tiny insects. If you find hornworms, pick them off by hand — they are large and straightforward to spot. For whiteflies or mites, spray the undersides of leaves with water to dislodge them, or use neem oil or insecticidal soap if the problem is severe.
For leaf diseases, remove the affected leaf and improve air circulation by pruning lower branches. If the problem spreads, spray with a fungicide labeled for tomatoes. Copper and sulfur are organic options; chlorothalonil and mancozeb are synthetic. Always follow the label instructions and stop spraying 7 to 14 days before you harvest, depending on the product.
Pinch off flowers in the first 3 to 4 weeks to encourage root and stem growth
If your tomato plant flowers very early — within the first 3 to 4 weeks after planting — pinch off those flowers. This sounds counterintuitive, but it works. Early flowers often drop without setting fruit anyway, and removing them lets the plant put energy into building a strong root system and sturdy stem. Once the plant is established, it will produce far more fruit.
After the first month, let all flowers stay. The plant is ready to make fruit now, and you want it to.
Frequently Asked Questions
How often should I water tomatoes in hot weather?
In temperatures above 85°F, check the soil every day. You may need to water daily or even twice a day if the soil is sandy or the pot is small. The key is consistent moisture — let the soil dry slightly between waterings, but do not let it bake hard. Mulch around the base with 2 to 3 inches of straw or wood chips to keep the soil cooler and retain moisture.
What does blossom end rot look like, and how do I prevent it?
Blossom end rot is a dark, sunken spot on the bottom of the fruit. It is caused by inconsistent watering and low calcium in the soil. Prevent it by watering deeply and regularly, and by adding crushed eggshells or gypsum to the soil at planting time. Once a fruit shows the spot, it will not heal — remove it and focus on preventing it on new fruit.
Can I grow tomatoes in a pot, and what size do I need?
Yes. Use a pot at least 5 gallons for determinate varieties and 10 gallons for indeterminate types. Larger is better — bigger pots hold more soil and moisture, so the plant is less stressed. Make sure the pot has drainage holes. Water potted tomatoes more often than in-ground plants because the soil dries faster.
When should I stop watering and feeding tomatoes?
Stop feeding about 4 weeks before your first expected frost date. Continue watering until the plant dies or you harvest the last fruit. Watering late in the season helps the fruit ripen and improves flavor.
Do I need to remove all the leaves to ripen green tomatoes at the end of the season?
No. Removing too many leaves exposes the fruit to sunscald (white or yellow patches). If you have green tomatoes in late summer, stop pruning and let the plant keep its foliage. The fruit will ripen slower, but it will ripen. If frost is coming, pick the green tomatoes and ripen them indoors in a paper bag with a ripe banana or apple.