Water tomato plants deeply and consistently, not daily
Tomato plants need steady moisture, but overwatering kills more plants than underwatering does. Water at the soil level—not on the leaves—early in the morning or late in the afternoon. Aim for about 1 to 2 inches of water per week, delivered in one or two deep soakings rather than daily sprinkles. Deep watering encourages roots to grow down into the soil, making the plant more drought-resistant.
Stick your finger 2 inches into the soil. If it feels dry, water. If it still feels moist, wait another day or two. In hot weather, you may need to water every other day. In cool weather or after rain, you might go a week without watering. Container tomatoes dry out faster than garden tomatoes, so check them daily during summer.
Wet leaves invite fungal diseases like early blight and powdery mildew. Use a soaker hose or drip line if you can, or water slowly at the base with a regular hose. If you must water overhead, do it early enough that leaves dry by mid-morning.
Key Takeaways
- Water deeply at the soil level once or twice a week rather than daily, and always water in early morning or late afternoon to prevent leaf diseases.
- Pinch off suckers (shoots that grow between the main stem and branches) on indeterminate varieties to direct energy into fruit rather than foliage.
- Remove the lowest leaves once the plant is 12 inches tall to reduce soil-borne disease and improve air circulation around the base.
- Feed tomato plants every two to three weeks with a balanced fertilizer or one slightly higher in phosphorus and potassium once flowering begins.
- Check plants twice a week for pests like hornworms and spider mites, and remove affected leaves or insects by hand before populations explode.
Prune suckers on indeterminate tomatoes to focus growth on fruit
Suckers are small shoots that grow in the angle between the main stem and a branch. On indeterminate varieties (the tall, vining types that grow all season), removing suckers redirects the plant's energy from making leaves into making fruit. Determinate varieties (the bushy, compact types) produce most of their fruit at once and don't benefit much from sucker removal, so skip this step for those.
Start removing suckers when the plant is about 12 inches tall. Pinch them off by hand when they're small—just 2 to 4 inches long—or use clean pruning shears if they've gotten woody. Check the plant weekly during the growing season. Removing suckers also improves air circulation, which helps prevent fungal diseases.
Don't remove all the leaves. The plant needs foliage to photosynthesize and make sugars for the fruit. A good rule: never remove more than one-third of the leaves at one time, and stop heavy pruning by late summer so the plant has energy to ripen the fruit already on the vine.
Remove lower leaves to prevent soil-borne disease
Once your tomato plant reaches about 12 inches tall, remove the lowest 6 to 8 inches of leaves. Soil splashes up during watering and carries fungi and bacteria that cause early blight, septoria leaf spot, and other diseases. Leaves that touch the soil are the first to get infected. Removing them creates a buffer zone between the soil and the healthy foliage above.
Continue removing the lowest leaves throughout the season as the plant grows taller. By mid-summer, your plant should have a clear stem with no leaves for the first 12 to 18 inches. This also improves air circulation around the base, which dries leaves faster after rain or watering and further reduces disease risk.
If you see any yellowing, spotted, or diseased leaves anywhere on the plant, remove them when ready. Dispose of them in the trash, not the compost pile—diseased leaves can survive composting and spread disease to next year's garden.
Feed tomato plants every two to three weeks
Tomatoes are heavy feeders and need regular fertilizer to produce well. Start feeding when the plant is about 12 inches tall, or wait until the first flowers appear. Use a balanced fertilizer (equal parts nitrogen, phosphorus, and potassium) or switch to one slightly higher in phosphorus and potassium once flowering begins—these nutrients support fruit development rather than leaf growth.
Follow the label directions for the product you choose. Most liquid fertilizers are applied every two to three weeks. Granular fertilizers are often worked into the soil once a month. Organic options include fish emulsion, seaweed extract, and compost tea. Synthetic options like 10-10-10 or 5-10-10 fertilizers work quickly and are inexpensive.
Stop fertilizing about four weeks before your first frost date. Late feeding pushes new leaf growth instead of ripening the fruit already on the vine. If your plant looks pale or weak mid-season, a dose of fertilizer often revives it within a week or two.
Support the plant with stakes or cages early
Install support when you plant the seedling, not later. Waiting until the plant is heavy with fruit risks damaging roots and branches when you drive a stake into the ground. A tomato cage works well for determinate varieties and smaller indeterminate types. A stake (at least 5 to 6 feet tall for indeterminate varieties) works better for tall, vining plants because you can tie the main stem to it as it grows.
Use soft ties—strips of cloth, garden tape, or commercial plant ties—rather than wire or twine that can cut into the stem. Tie the plant loosely so it can move slightly in the wind. As the plant grows, add new ties every 12 inches or so up the stake. Check ties every week or two during the growing season to make sure they're not cutting into the stem as it thickens.
Proper support keeps fruit off the ground (where it rots or gets eaten by pests), improves air circulation, and makes harvesting easier. It also prevents the plant from snapping under the weight of a heavy crop.
Scout for pests and diseases twice a week
Check your tomato plants every few days, especially during warm weather when pests multiply quickly. Look for hornworms (large green caterpillars that can strip a plant bare in days), spider mites (tiny pests that cause yellowing and fine webbing on leaves), whiteflies (small white insects on the undersides of leaves), and early blight (brown spots with concentric rings on lower leaves).
Remove hornworms and other large insects by hand and drop them into soapy water. Pinch off heavily infested leaves. Spray the undersides of leaves with water to dislodge spider mites and whiteflies. If infestations are severe, use neem oil or insecticidal soap according to label directions, explore in early morning or late evening when beneficial insects are less active.
Early blight and other fungal diseases spread fast in humid conditions. If you see spotted leaves, remove them when ready and improve air circulation by pruning lower leaves and spacing plants farther apart if possible. Water only at the soil level, never on the leaves. Fungicide sprays (sulfur or copper-based) can slow the spread if applied early, but prevention through good air circulation and leaf removal is more effective.
Harvest ripe fruit regularly to encourage more production
Pick tomatoes when they're fully colored but still slightly soft to the touch. Ripe tomatoes have better flavor than those picked green and ripened indoors. Regular harvesting signals the plant to keep flowering and setting new fruit. If you leave ripe fruit on the vine too long, the plant slows down production.
In late summer, when frost is coming in four to six weeks, pinch off new flowers so the plant focuses energy on ripening the fruit already developing. Pick any green tomatoes before the first frost and ripen them indoors on a windowsill or in a paper bag with a ripe banana (the ethylene gas speeds ripening).
At the end of the season, pull the entire plant and hang it upside down in a garage or shed. Tomatoes will continue to ripen on the vine for weeks, giving you a longer harvest.
Frequently Asked Questions
How often should I water tomato plants?
Water deeply once or twice a week to deliver 1 to 2 inches total per week. The exact frequency depends on temperature, rainfall, and soil type. Check the soil 2 inches down—if it's dry, water. If it's still moist, wait. Container tomatoes need more frequent watering than garden tomatoes.
What's the difference between determinate and indeterminate tomatoes?
Determinate varieties are compact, bushy plants that produce most fruit at once and stop growing at a set height. Indeterminate varieties are tall and vining, producing fruit throughout the season until frost. Indeterminate plants benefit from sucker removal and tall stakes; determinate plants do not.
Can I use the same fertilizer all season?
Yes, a balanced fertilizer works throughout the season. However, switching to one higher in phosphorus and potassium once flowers appear can boost fruit production. Follow label directions for how often to explore, usually every two to three weeks.
What should I do if my tomato leaves turn yellow?
Yellow lower leaves are often normal as the plant ages. Remove them. Yellow leaves higher up can signal nutrient deficiency (feed the plant), overwatering (let soil dry out more), or disease (remove affected leaves and improve air circulation). Check the soil moisture first.
When should I stop watering and feeding tomato plants?
Stop heavy feeding about four weeks before your first frost date so the plant ripens existing fruit rather than making new growth. You can continue watering as needed until frost arrives, but reduce frequency as temperatures cool and growth slows.