Start with the right variety for your climate and space

The tomato variety you choose matters more than almost anything else. Determinate tomatoes grow to a fixed size, stop growing, and produce most of their fruit at once—good for canning or if you have limited space. Indeterminate tomatoes keep growing and producing fruit all season, which means more tomatoes over time but also more pruning and staking. Check your seed packet or nursery label for your USDA hardiness zone; a tomato bred for zone 9 will struggle in zone 5, no matter how well you care for it.

If you have less than six hours of direct sun daily, choose varieties labeled as shade-tolerant: 'Sungold', 'Early Girl', and 'Stupice' handle partial light better than large slicing types. If you garden in a container, look for compact varieties like 'Tiny Tim' or 'Patio' rather than full-size plants that will outgrow their pot and produce poorly. Seed catalogs and plant labels tell you days to maturity—count backward from your first frost date to make sure the variety will finish before cold weather arrives.

Key Takeaways

  • Tomatoes need at least six hours of direct sun daily and soil that drains well but holds moisture; poor drainage causes root rot and disease.
  • Plant seedlings deeper than they grew in their pot—bury the stem up to the first true leaves so roots develop along the buried stem.
  • Water at the soil level early in the morning, not from above, to keep leaves dry and prevent fungal disease.
  • Indeterminate varieties need pruning and staking or caging to keep fruit off the ground and improve air flow around the plant.
  • Blossom end rot (dark spots on the bottom of fruit) signals uneven watering; water deeply and consistently rather than in bursts.

Prepare soil that holds moisture without staying wet

Tomatoes are heavy feeders and need rich, well-draining soil. Before planting, work compost or aged manure into the top 8 to 10 inches of soil. If your soil is clay-heavy and stays soggy after rain, add compost to break up the clay and improve drainage—tomatoes in waterlogged soil develop root rot and fungal diseases like early blight. If your soil is sandy and dries out fast, compost helps it hold water longer.

Test your soil pH if you can; tomatoes prefer slightly acidic soil between 6.0 and 6.8. If you are planting in containers, use potting mix, not garden soil—potting mix is formulated to drain and hold air. A 5-gallon bucket works for one determinate plant; indeterminate varieties need at least a 10-gallon container to produce well all season.

Plant seedlings deep and space them for air flow

When you transplant seedlings outdoors, bury the stem deeper than it grew in the pot. Tomato stems develop roots all along their length, so burying the stem up to the first set of true leaves creates a stronger root system. Remove the lower leaves before planting so no foliage sits in contact with soil, where disease spores live.

Space plants 24 to 36 inches apart depending on variety—indeterminate types need more room because they grow larger and bushier. Crowded plants trap moisture and create conditions for fungal disease. If you are planting in rows, orient them north to south so both sides get sun during the day.

Water deeply and consistently at soil level

Tomatoes need about 1 to 2 inches of water per week, delivered at the soil level, not from above. Water early in the morning so any splash dries quickly. Wet foliage invites early blight, septoria leaf spot, and other fungal diseases that spread in humid conditions. Use a soaker hose or drip line if you can—they deliver water slowly to the root zone and keep leaves dry.

Inconsistent watering causes blossom end rot, the dark, sunken spots that appear on the bottom of fruit. This happens when the plant cannot move calcium to the fruit because the soil alternates between wet and dry. Water deeply enough that the soil is moist 6 to 8 inches down, then let the top inch dry slightly before watering again. In hot weather, this may mean daily watering; in cool weather, every two or three days.

Stake or cage indeterminate plants and prune for air flow

Indeterminate tomatoes grow tall and need support. Drive a stake or cage into the soil at planting time so you do not damage roots later. As the plant grows, tie the main stem loosely to the stake with soft ties—cloth strips or tomato clips work better than wire, which can cut into the stem. Space ties every 8 to 12 inches.

Prune suckers—the shoots that grow in the angle between the main stem and branches—to direct energy into fruit production and improve air flow. Remove lower leaves once the plant is established and producing fruit; this keeps foliage off the soil and reduces disease. Do not remove so many leaves that fruit gets sunburned, but aim for enough space between branches that air moves freely through the plant.

Feed regularly once flowering begins

Tomatoes need nitrogen early to build leaves and stems, then shift to phosphorus and potassium once they start flowering to support fruit production. A balanced fertilizer like 10-10-10 works for the first month. Once flowers appear, switch to a lower-nitrogen formula like 5-10-10 or use a tomato-specific fertilizer. Follow the package rate—too much nitrogen produces lots of leaves but few tomatoes.

Feed every two to three weeks during the growing season. If you worked compost into the soil at planting, you may not need to feed as often. Slow-release fertilizers release nutrients gradually and require fewer applications than liquid fertilizers.

Watch for common pests and diseases

Hornworms are large green caterpillars that eat leaves and fruit; hand-pick them or spray with Bacillus thuringiensis (Bt), a natural insecticide that targets caterpillars. Whiteflies cluster on the undersides of leaves and weaken the plant; spray the undersides with insecticidal soap or neem oil. Spider mites cause yellowing and fine webbing; increase humidity by misting or spraying with water, or use neem oil.

Early blight appears as brown spots with concentric rings on lower leaves and spreads upward. Remove affected leaves and improve air flow by pruning. Septoria leaf spot looks like small circular spots with dark borders and gray centers; remove infected leaves and avoid wetting foliage. If disease is severe, spray with a fungicide labeled for tomatoes, following the label rate and harvest interval.

Harvest when fruit is fully colored but still firm

Tomatoes develop their best flavor when they ripen on the vine, but you can pick them at the "breaker stage"—when the first blush of color appears—and let them finish ripening indoors if pests or disease are a problem. Ripe tomatoes come off the vine with a gentle twist; if you have to pull hard, they are not quite ready.

In late summer, pinch off new flowers and the growing tips of indeterminate plants so the plant directs energy into ripening existing fruit before frost arrives. If frost is coming and you have green tomatoes still on the vine, pick them and ripen them indoors in a paper bag with a ripe banana or apple, which release ethylene gas and speed ripening.

Frequently Asked Questions

Why are my tomato flowers falling off without making fruit?

Flowers drop when temperatures are too hot (above 90°F at night) or too cold (below 55°F at night), when the plant is stressed by inconsistent watering, or when nitrogen is too high. Keep soil consistently moist, avoid over-fertilizing with nitrogen, and wait for temperatures to moderate. Some varieties are more heat-tolerant than others.

Can I grow tomatoes in a pot on a patio?

Yes, but use a container at least 5 gallons for determinate varieties and 10 gallons for indeterminate types. Use potting mix, not garden soil. Containers dry out faster than garden beds, so check soil moisture daily and water when the top inch is dry. Feed every two weeks because water drains nutrients out of the pot.

What should I do with green tomatoes at the end of the season?

Pick them before the first frost and ripen them indoors. Place them in a single layer in a cardboard box or paper bag at room temperature, away from direct sun. Add a ripe banana or apple to speed ripening. They will ripen in one to three weeks depending on how mature they were when picked.

How do I prevent early blight from spreading?

Remove infected leaves as soon as you see them, dispose of them in the trash (not compost), and wash your hands and tools before touching other plants. Water at soil level only, not from above. Improve air flow by pruning lower branches and spacing plants far enough apart that air moves freely.

Do I need to prune determinate tomatoes?

Determinate varieties need less pruning than indeterminate types. Remove lower leaves once the plant is established to reduce disease, and remove any dead or diseased foliage. You do not need to remove suckers, but removing a few can improve air flow without reducing fruit production.