Water your tomato plant deeply and consistently
Tomato plants need steady moisture to produce fruit and avoid problems like blossom-end rot and fruit cracking. Water at the soil level rather than overhead—wet leaves invite fungal disease. The soil should feel damp a few inches down, not soggy. Most tomato plants need water every two to three days in warm weather, but this depends on your soil type, rainfall, and how hot it is where you live.
The best time to water is early morning, so any splash on the leaves dries quickly. If you use a soaker hose or drip line, you'll lose less water to evaporation and keep the foliage dry. Mulch around the base with 2 to 3 inches of straw or wood chips to hold moisture in the soil and keep roots cooler during heat waves.
Key Takeaways
- Water at soil level in the early morning, aiming for damp (not soggy) soil a few inches down every two to three days in warm weather.
- Pinch off suckers—the shoots that grow between the main stem and branches—on indeterminate varieties to direct energy into fruit instead of leaves.
- Support the plant with a cage, stake, or string as it grows so branches don't snap under the weight of fruit.
- Watch for yellowing leaves, brown spots, or soft spots on fruit, which signal disease or pest problems that spread quickly if left alone.
- Stop fertilizing once the plant flowers; too much nitrogen pushes leafy growth and delays ripening.
Support the plant as it grows taller
Tomato plants get heavy once fruit sets. Without support, branches break, fruit touches the ground and rots, and air can't circulate around the plant. Install a cage, stake, or string trellis when you plant—waiting until the plant is large makes it harder to tie without damaging stems.
For determinate varieties (bush types that stay compact), a sturdy cage is usually enough. For indeterminate varieties (vining types that grow all season), a tall stake or string system works better because the plant will outgrow a cage. Tie the stem loosely to the support with soft material like cloth strips or plant tape—tight ties cut into the stem as it thickens.
Pinch off suckers on vining varieties
On indeterminate tomatoes, suckers are shoots that grow in the angle between the main stem and a branch. They look like small stems with leaves. If you leave them, they grow into full branches that produce leaves instead of fruit, shading the plant and wasting energy.
Pinch off suckers when they're small—just snap them off with your fingers or a clean knife. Do this once a week during the growing season. Determinate (bush) varieties don't need this; they're bred to stay bushy and produce most fruit at once.
Fertilize early, then stop
Tomato plants are heavy feeders and need nutrients to grow and fruit. At planting time, work compost or a balanced fertilizer into the soil. Once the plant starts flowering, switch to a fertilizer higher in phosphorus and potassium (the second and third numbers on the bag) and lower in nitrogen—something like 5-10-10 instead of 10-10-10.
Stop fertilizing once fruit is setting and ripening. Extra nitrogen at this stage pushes leafy growth and delays ripening. If leaves look pale or growth slows, a light feeding mid-season is fine, but less is usually better. Overfed plants produce lots of foliage and few tomatoes.
Watch for common pests and diseases
Tomato plants attract hornworms (large green caterpillars), spider mites, and whiteflies. Check the undersides of leaves weekly. If you see damage or insects, spray with insecticidal soap or neem oil early in the morning or late in the evening. Remove heavily infested leaves by hand.
Fungal diseases like early blight (brown spots with rings on lower leaves) and powdery mildew (white coating on leaves) spread in wet conditions. Space plants so air flows between them, water at soil level only, and remove infected leaves as soon as you spot them. If disease is severe, prune off the bottom 6 to 12 inches of the plant to improve air flow. Blossom-end rot—a dark, sunken spot on the bottom of the fruit—signals inconsistent watering or low calcium; keep soil moisture steady and avoid overhead watering.
Prune lower leaves as the plant matures
Once the plant is 2 to 3 feet tall and has set fruit, remove the lowest 6 to 12 inches of leaves. These leaves are oldest, most likely to carry disease, and contribute little to fruit production. Removing them improves air flow, reduces disease pressure, and makes it easier to water at soil level without splashing leaves.
Continue removing yellowing or spotted leaves throughout the season. Never remove more than one-third of the foliage at once—the plant needs leaves to photosynthesize and ripen fruit. Stop heavy pruning about four weeks before your first frost date so the plant has enough leaves to finish ripening the remaining fruit.
Harvest ripe fruit and manage end-of-season ripening
Pick tomatoes when they're fully colored but still slightly soft—they'll taste better than hard, picked-too-early fruit. Ripe tomatoes come off the vine with a gentle twist. If frost is coming and you have green tomatoes still on the plant, pick them and set them on a windowsill indoors; they'll ripen slowly over a few weeks in room temperature.
Once nighttime temperatures drop below 55°F, tomatoes stop ripening on the vine. At that point, pull the entire plant and hang it upside down in a garage or shed, or pick all remaining fruit and ripen it indoors. This gives you a few extra weeks of harvest before the season ends.
Frequently Asked Questions
Why are my tomato leaves turning yellow?
Lower leaves yellow naturally as the plant ages and should be removed. If yellowing spreads up the plant or appears suddenly on new growth, it usually signals nitrogen deficiency, overwatering, or disease. Check soil moisture first—soggy soil causes root problems. If soil is moist but not waterlogged, a light fertilizer feeding may help. If you see spots or patterns on the yellow leaves, it's likely disease; remove those leaves and improve air flow.
How often should I fertilize my tomato plant?
At planting, work compost or balanced fertilizer into the soil. Once flowers appear, feed every two to three weeks with a phosphorus-rich formula until fruit starts ripening, then stop. Overfertilizing pushes leaves at the expense of fruit. If growth slows mid-season, one light feeding is fine, but watch for signs of excess nitrogen—lots of leaves, few tomatoes.
Can I grow tomatoes in a pot?
Yes, but use a large container—at least 5 gallons for determinate varieties, 10 gallons or larger for indeterminate types. Pots dry out faster than garden soil, so you'll water more often, sometimes daily in heat. Use quality potting soil (not garden soil), add compost at planting, and fertilize more frequently because water drains nutrients away. All other care—watering, support, pruning, pest management—stays the same.
What's the difference between determinate and indeterminate tomatoes?
Determinate (bush) varieties grow to a set size, flower all at once, and produce most fruit in a short window—good for canning. Indeterminate (vining) varieties grow all season, flower continuously, and produce fruit until frost—good for fresh eating. Indeterminate plants need taller support, regular sucker removal, and pruning. Determinate plants stay compact and need less maintenance but produce less total fruit over the season.
When should I stop watering my tomato plant?
Keep watering until the plant dies back from frost or you pull it up at season's end. Consistent moisture is important right up to harvest—inconsistent watering late in the season causes fruit cracking and blossom-end rot. Once nighttime temperatures drop below 55°F and fruit stops ripening on the vine, you can reduce watering slightly, but don't let the plant dry out completely.