Start with the right soil and sunlight
Tomatoes need at least six to eight hours of direct sunlight each day to produce fruit. Plant them in a spot that gets morning sun and afternoon sun without shade from buildings or trees. If your yard does not have that much light, container growing on a south-facing patio or balcony works, as long as you can move the pot to follow the sun.
Use soil that drains well. Garden soil mixed with compost works better than plain garden soil alone. If you are planting in containers, use potting mix rather than garden soil — potting mix is lighter and holds moisture more evenly. Fill containers at least twelve inches deep for determinate varieties (bush types) and eighteen inches or deeper for indeterminate varieties (vining types that grow all season).
Before planting, work compost or aged manure into the top six inches of garden soil. Tomatoes are heavy feeders and will pull nutrients from the soil throughout the growing season.
Key Takeaways
- Tomatoes need six to eight hours of direct sun daily and soil that drains well, whether in the ground or in containers at least twelve inches deep.
- Plant seedlings deeper than they grew in their starter pot — bury the stem up to the first true leaves to encourage a stronger root system.
- Water at the soil level early in the morning, not on the leaves, to prevent disease and keep moisture consistent as the plant grows.
- Support indeterminate varieties with stakes or cages from the time you plant them, and prune suckers (shoots between the main stem and branches) on vining types to direct energy to fruit.
- Harvest tomatoes when they reach full color but are still slightly firm, or pick them at the breaker stage (first blush of color) and ripen them indoors if pests or disease pressure is high.
Plant seedlings at the right depth
Start seeds indoors six to eight weeks before your last spring frost, or buy seedlings from a nursery. Seedlings are ready to transplant outdoors when they have their first true leaves (the second set of leaves that appear) and are four to six inches tall.
Harden off seedlings by setting them outside in a sheltered spot for a few hours each day over one week before planting them in the garden. This acclimates them to wind and direct sun. When you plant them in the ground or in containers, bury the stem deeper than it was growing in the starter pot — bury it up to the first set of true leaves. Tomato stems will develop roots all along the buried portion, creating a stronger root system that can support a larger plant and heavier fruit load.
Space plants two to three feet apart for determinate varieties and three to four feet apart for indeterminate varieties. Indeterminate types grow taller and wider and need more room for air circulation.
Water consistently and at the right time
Water at the soil level in the early morning, not on the leaves. Wet leaves invite fungal diseases like early blight and powdery mildew. Tomatoes need about one to two inches of water per week, either from rain or from you. In hot weather or in containers, they may need water more often.
Inconsistent watering causes problems: too little water stresses the plant and can cause blossom end rot (a dark sunken spot on the bottom of the fruit), and too much water can crack ripe fruit or cause roots to rot. A soaker hose or drip line delivers water directly to the soil and keeps it steady. If you hand-water, water deeply so the moisture reaches the root zone, which is at least six inches down.
Mulch around the base of the plant with two to three inches of compost or straw to keep soil temperature even and reduce water loss on hot days. Keep mulch a few inches away from the stem to prevent rot.
Support vining plants and manage growth
Determinate varieties (bush types) stay compact and do not need much support. Indeterminate varieties (vining types) grow continuously throughout the season and can reach six feet or taller. Install stakes or cages at planting time, before the plant is large, so you do not damage roots later.
On indeterminate varieties, you can prune suckers — the shoots that grow between the main stem and the branches. Removing suckers directs the plant's energy into fruit production rather than leafy growth. On determinate varieties, pruning is less important because the plant naturally stops growing at a certain height.
Tie the main stem loosely to the stake with soft twine or cloth strips as the plant grows. Avoid tying too tightly, which can cut into the stem as it thickens.
Feed the plant as it grows
Tomatoes need nitrogen early in the season to build leaves and stems, and phosphorus and potassium later to support flowering and fruit development. A balanced fertilizer like 10-10-10 works for the first month. Once the plant begins to flower, switch to a fertilizer lower in nitrogen, like 5-10-10, to avoid encouraging too much leaf growth at the expense of fruit.
Feed every two to three weeks once the plant is established. Follow the package directions for the amount — too much fertilizer can burn roots or cause the plant to grow leaves instead of fruit. Compost worked into the soil at planting time provides slow, steady nutrition throughout the season and may be all you need if your soil is already rich.
Harvest at the right stage
Pick tomatoes when they reach full color but are still slightly firm. A ripe tomato yields a little to gentle pressure but is not soft. Tomatoes continue to ripen after picking, so you can harvest them at the breaker stage — when the first blush of color appears — and let them finish ripening on the counter indoors. This is useful if you see disease pressure building or if pests are damaging ripe fruit on the vine.
Harvest regularly to encourage the plant to keep producing. Leaving ripe fruit on the vine signals the plant that its job is done, and it may slow or stop flowering. In late summer, pinch off new flower clusters so the plant directs energy into ripening the fruit already on the vine rather than starting new fruit that will not mature before frost.
Watch for common pests and diseases
Early blight appears as brown spots with concentric rings on lower leaves and spreads upward. Remove affected leaves as soon as you see them, water at soil level only, and improve air circulation by pruning lower branches. Powdery mildew looks like a white coating on leaves and thrives in humid conditions — thin the plant and space it away from other plants to increase airflow.
Hornworms are large green caterpillars that eat leaves and fruit. Hand-pick them or spray with spinosad, an organic insecticide. Whiteflies cluster on the undersides of leaves and weaken the plant by sucking sap. Spray the undersides of leaves with insecticidal soap or neem oil every few days until they are gone.
Blossom end rot is a dark sunken spot on the bottom of the fruit caused by calcium deficiency, usually triggered by inconsistent watering. Keep soil moisture steady and mulch to prevent it. Affected fruit cannot be saved, but consistent watering will prevent it on new fruit.
Frequently Asked Questions
Can I grow tomatoes in a pot on a balcony?
Yes. Use a container at least twelve inches deep filled with potting mix, place it where it gets six to eight hours of direct sun, and water daily in hot weather. Determinate varieties and smaller heirloom types work better in containers than large indeterminate varieties, which need more root space.
Why are my tomatoes not turning red?
Tomatoes need consistent warmth and sunlight to ripen. If nights are below 55 degrees Fahrenheit, ripening slows or stops. If the plant is shaded, move it to a sunnier spot or prune excess leaves to let light reach the fruit. Overwatering or overfertilizing with nitrogen can also delay ripening by encouraging leaf growth.
How do I know when to stop watering before frost?
In late summer, reduce watering slightly to encourage the plant to ripen existing fruit rather than produce new growth. Stop fertilizing four to six weeks before your first expected frost so the plant focuses on ripening rather than new leaves. You can still water if the soil is dry, but do not feed.
What is the difference between determinate and indeterminate tomatoes?
Determinate varieties are bush types that grow to a fixed height (usually two to four feet), flower all at once, and produce most of their fruit in a short window. Indeterminate varieties are vining types that grow continuously, flower throughout the season, and produce fruit until frost. Indeterminate types are better for a long harvest; determinate types are better for canning because the fruit ripens all at once.
Can I save seeds from my tomatoes to plant next year?
Yes, but only from heirloom or open-pollinated varieties. Hybrid tomatoes will not produce seeds that grow into plants identical to the parent. Scoop seeds and pulp into a jar, add a little water, let them ferment for two to three days, rinse them, dry them completely on a paper towel, and store them in a cool, dry place.