Water deeply and consistently, but not every day
Tomato plants need 1 to 2 inches of water per week, delivered in one or two deep soakings rather than daily sprinkles. Water at the soil level, not on the leaves — wet foliage invites fungal disease. The soil should feel moist 2 inches down when you press your finger into it; if it is bone-dry, the plant will drop flowers and fruit.
How often you water depends on your climate, soil type, and whether the plant is in a pot or the ground. Sandy soil dries faster than clay. Container plants dry out much faster than garden soil. In hot weather, you may water every two or three days; in cool weather, every five to seven days. The goal is steady moisture, not soggy roots — overwatering kills tomatoes as surely as drought does.
Water early in the morning so any splash on the leaves dries quickly. If you live in a dry climate or have sandy soil, mulch around the base with 2 to 3 inches of straw or wood chips to hold moisture and regulate soil temperature.
Key Takeaways
- Water at soil level once or twice a week for 1 to 2 inches total, aiming for moist but not waterlogged soil.
- Feed with a balanced fertilizer every two to three weeks once the plant flowers, or use a slow-release fertilizer at planting time.
- Support the plant with a stake or cage early — waiting until the plant is heavy with fruit makes tying difficult and risks breaking branches.
- Remove the bottom leaves once the plant is 12 inches tall to reduce fungal disease and improve air flow.
- Pinch off suckers (shoots between the main stem and branches) on indeterminate varieties to direct energy toward fruit instead of foliage.
Feed the plant once flowers appear
Tomatoes do not need fertilizer at planting time if your soil is decent — too much nitrogen early on produces leafy plants with few flowers. Once the plant flowers, feed every two to three weeks with a balanced fertilizer (equal parts nitrogen, phosphorus, and potassium) or a formula slightly higher in phosphorus and potassium, which promote fruiting.
You have two main routes: liquid fertilizer mixed into water every two to three weeks, or a slow-release granular fertilizer worked into the soil at planting time. Liquid is easier to adjust if the plant looks hungry; slow-release is simpler if you do not want to remember a schedule. Follow the label rate — more fertilizer does not speed ripening and can burn roots.
If leaves turn yellow while the plant is still growing, the plant may need nitrogen. If fruit is slow to set or small, phosphorus or potassium may be low. A soil test from your local extension office tells you what your soil actually contains, which saves guessing.
Install support early, before the plant is heavy
Stake or cage your tomato plant when you plant it or within the first two weeks of growth. Waiting until the plant is tall and heavy makes tying difficult, risks breaking branches, and leaves the root system exposed if you drive a stake in later.
A cage (the wire cylinder kind) works well for determinate varieties, which grow to a set height and stop. Push the cage into the soil so it stands firm, and the plant will grow up through it. A stake (a 5- to 6-foot wooden or bamboo pole) works better for indeterminate varieties, which grow taller and need tying as they climb. Tie the main stem loosely to the stake with soft string or cloth strips every 8 to 12 inches, leaving room for the stem to thicken.
Without support, branches break under the weight of fruit, fruit touches the soil and rots, and air cannot flow through the plant, which invites disease. Even a short stake is better than nothing.
Remove lower leaves and thin out dense foliage
Once the plant is 12 inches tall, remove the bottom 6 to 8 inches of leaves. These lower leaves are most likely to touch soil, pick up fungal spores, and spread disease upward. Removing them also improves air flow, which dries the foliage faster after rain or watering and reduces fungal problems like early blight and septoria leaf spot.
As the plant grows, continue removing leaves that show spots, yellowing, or signs of disease. If the foliage is so dense that you cannot see light passing through the canopy, thin it out — the plant needs air movement more than it needs every leaf.
Do your pruning in the morning on a dry day, and wash your hands or dip your pruners in a 10 percent bleach solution (1 part bleach to 9 parts water) between cuts if you are removing diseased leaves. This prevents spreading disease from one plant to another.
Pinch off suckers on indeterminate varieties
Suckers are shoots that grow in the angle between the main stem and a branch. On indeterminate varieties (the tall, vining kinds that grow all season), removing suckers directs the plant's energy into fruit rather than foliage. On determinate varieties (the bush types), suckers are less of a problem and you can leave them.
Pinch off suckers when they are small — just an inch or two long — by snapping them off with your fingers. If you wait until they are thick, use pruners. You do not need to remove every sucker, but removing the ones on the lower half of the plant keeps the plant open and manageable.
Indeterminate plants can grow 6 feet or taller and produce fruit all season. Determinate plants usually max out at 3 to 4 feet and produce most of their fruit in a short window. Know which type you planted so you know how much pruning makes sense.
Watch for common pests and diseases
Hornworms are large green caterpillars that can strip a plant bare. Check the undersides of leaves and remove them by hand, or spray with spinosad (an organic insecticide) if the infestation is heavy. Whiteflies and spider mites cause yellowing and stippling on leaves; spray the undersides of leaves with water or insecticidal soap.
Early blight shows as brown spots with concentric rings on lower leaves and spreads upward. Remove affected leaves and improve air flow. Septoria leaf spot looks like small round spots with dark borders and gray centers. Again, remove leaves and thin foliage. Blossom end rot — a dark, sunken spot on the bottom of the fruit — is caused by inconsistent watering and low calcium; keep soil moisture steady and mulch to regulate it.
Most problems are easier to prevent than to cure. Consistent watering, good air flow, removing lower leaves, and spacing plants so they do not touch prevent most fungal diseases. If you do see disease, remove affected leaves when ready and do not compost them — throw them in the trash.
Harvest when fruit is fully colored but still firm
Pick tomatoes when they are fully colored but still slightly firm — they will soften on the counter over a day or two. Ripe tomatoes come off the vine with a gentle twist; if you have to pull hard, they are not quite ready. Picking ripe fruit encourages the plant to keep flowering and setting new fruit.
If frost is coming and you have green tomatoes still on the vine, pick them and ripen them indoors on a windowsill or in a paper bag with a ripe banana (the ethylene gas speeds ripening). Tomatoes will not ripen once the plant dies back, so do not leave them on the vine hoping for color.
A healthy tomato plant can produce fruit for three to four months in warm climates, or until the first frost in cooler areas. Once the plant stops flowering and setting new fruit, or once disease becomes unmanageable, pull it out and compost it (unless it had late blight, which can survive in compost).
Frequently Asked Questions
How often should I water if my tomato is in a pot?
Container tomatoes dry out faster than garden soil and may need water every two to three days in hot weather. Check the soil 2 inches down — if it is dry, water deeply until it drains from the bottom. In cool weather, every four to five days may be enough. Mulch the top of the pot to slow evaporation.
Can I use regular garden fertilizer on tomatoes?
Yes, as long as it is balanced or slightly higher in phosphorus and potassium. A 10-10-10 or 5-10-10 formula works fine. Avoid fertilizers very high in nitrogen (the first number), which push leaf growth at the expense of flowers and fruit. Always follow the label rate.
What is the difference between determinate and indeterminate tomatoes?
Determinate varieties grow to a set height (usually 3 to 4 feet), produce most fruit in a short window, and need less pruning. Indeterminate varieties grow tall all season (6 feet or more), produce fruit continuously, and benefit from staking and sucker removal. Check your seed packet or plant label to know which you have.
Why are my tomato flowers falling off without setting fruit?
Flowers drop when the plant is stressed — usually from inconsistent watering, temperature swings below 55°F at night, or too much nitrogen. Keep soil moisture steady, avoid overfeeding, and be patient. Once temperatures warm and watering settles into a rhythm, the plant will set fruit again.
Can I grow tomatoes in a pot all season?
Yes, but use a pot at least 5 gallons (for determinate varieties) or 10 gallons (for indeterminate). Larger pots hold moisture longer and give roots more room. You will water more often than in-ground plants, and you may need to feed more frequently since water drains nutrients out the bottom.