Start with seeds indoors or buy seedlings from a nursery

You can grow tomatoes two ways: start from seed indoors six to eight weeks before your last spring frost, or buy seedlings already started at a garden center and plant them directly outside. Starting from seed costs less and gives you more variety to choose from, but requires grow lights or a sunny windowsill and takes longer. Buying seedlings is faster and simpler if you want to harvest sooner — you'll be planting transplants that are already several inches tall instead of waiting for germination and growth indoors.

If you choose seeds, fill a seed tray or small pots with seed-starting mix (not garden soil), plant seeds about a quarter-inch deep, keep the soil moist but not waterlogged, and maintain a temperature between 70 and 80 degrees Fahrenheit. Seeds sprout in five to ten days. Once they have their first true leaves — the second set that appears — move them under grow lights positioned two to three inches above the seedlings, or place them in a south-facing window. Water from below by setting pots in a tray of water rather than pouring from above, which can cause damping off (a fungal disease that kills seedlings at soil level).

If you buy seedlings, look for stocky plants with dark green leaves and no flowers yet. Leggy, pale seedlings or ones already flowering will struggle after transplanting. Harden them off before planting outside by setting them in a sheltered spot for a few hours on day one, then gradually increasing outdoor time over seven to ten days.

Key Takeaways

  • Tomatoes need at least six to eight hours of direct sunlight daily, and eight to ten hours is better for faster growth and sweeter fruit.
  • Plant seedlings deeper than they grew in their pot — bury the stem up to the first true leaves, and roots will form along the buried stem for a stronger plant.
  • Space plants 24 to 36 inches apart depending on variety, because crowding reduces air flow and invites disease.
  • Water deeply and consistently at the soil level, aiming for one to two inches per week, and avoid wetting the leaves to prevent fungal problems.

Choose a location with full sun and well-draining soil

Tomatoes are heavy feeders and sun lovers. Pick a spot that gets at least six to eight hours of direct sunlight — ideally eight to ten hours. Morning sun is especially valuable because it dries dew off the leaves, which reduces disease. If your yard is shaded most of the day, tomatoes will grow slowly, produce fewer flowers, and the fruit that does form will be less sweet.

Soil matters as much as sunlight. Tomatoes prefer soil that drains well but holds moisture — a balance that sounds contradictory but straightforward means soil with organic matter mixed in. Before planting, work two to three inches of compost or aged manure into the top six to eight inches of soil. This improves drainage in clay soil and water retention in sandy soil. If you're planting in containers, use potting mix, not garden soil, which compacts in pots and suffocates roots.

Test your soil pH if possible. Tomatoes prefer slightly acidic soil between 6.0 and 6.8. If your soil is very alkaline (above 7.5), adding sulfur can lower it, but this takes time — start adjusting in fall for spring planting. If you're short on time, containers with fresh potting mix sidestep this problem entirely.

Plant seedlings after the last frost date in your area

Tomatoes are killed by frost. Planting too early is the most common mistake home growers make. Find your local last spring frost date by searching your zip code plus "frost date" or asking at a local garden center — it varies by region and can shift year to year. Wait until that date has passed and nighttime temperatures stay above 50 degrees Fahrenheit before moving seedlings outside.

When you're ready to plant, dig a hole slightly deeper than the seedling's root ball. Bury the stem up to the first set of true leaves — tomatoes will root along the buried stem, creating a stronger root system. Space plants 24 to 36 inches apart depending on the variety (check the seed packet or plant label). Determinate varieties (bush types) can be closer; indeterminate varieties (vining types) need more room.

Water thoroughly after planting and keep the soil consistently moist for the first two weeks while roots establish. A two-inch layer of mulch around each plant (but not touching the stem) helps retain moisture and keeps soil temperature steady.

Water deeply and consistently at soil level

Tomatoes need one to two inches of water per week, delivered as deep watering rather than frequent shallow sprinkling. Deep watering encourages roots to grow down into the soil, making plants more drought-tolerant. Shallow daily watering keeps roots near the surface where they dry out quickly and become stressed.

Water at the soil level, not on the leaves. Wet foliage invites fungal diseases like early blight and powdery mildew, especially in humid climates or when leaves stay wet overnight. The best time to water is early morning, so any accidental leaf wetting dries quickly. If you use a soaker hose or drip irrigation, water runs directly to the soil and never touches leaves — this is the ideal setup for tomatoes.

Check soil moisture by pushing your finger two inches into the soil. If it feels dry, water. If it's still moist, wait. Inconsistent watering — alternating between dry and soaked — causes problems like blossom end rot (a dark sunken spot on the fruit) and fruit cracking. Mulch helps regulate moisture by keeping soil temperature steady and reducing evaporation.

Support indeterminate varieties with stakes or cages

Indeterminate tomatoes (vining types that grow all season) need support to keep fruit off the ground and improve air circulation. Determinate varieties (bush types) may not need support, but staking them anyway improves air flow and makes harvesting easier. Install stakes or cages at planting time rather than later, when you risk damaging roots.

Cages work for smaller determinate varieties but often collapse under the weight of a full indeterminate plant. A sturdy stake — at least five to six feet tall for indeterminate types — is more reliable. Drive the stake into the ground at planting time, then loosely tie the main stem to the stake as it grows, using soft ties like cloth strips or tomato twine. Tie every eight to twelve inches of growth, leaving a little slack so the stem can expand.

Some growers use the Florida weave method: a single string run horizontally between stakes at intervals, with the plant woven through it as it grows. This works well for rows of tomatoes and uses less material than individual cages.

Fertilize every two to three weeks once flowering begins

Tomatoes are heavy feeders. If you worked compost or aged manure into the soil before planting, plants will have nutrients for the first few weeks. Once flowers appear, start fertilizing every two to three weeks. Use a balanced fertilizer like 10-10-10 or one slightly higher in phosphorus and potassium, like 5-10-10, which encourages flowering and fruiting rather than excessive leaf growth.

Follow the package directions for the amount — too much fertilizer, especially nitrogen, produces lots of leaves but few flowers. Liquid fertilizers work faster than granular ones if you need a quick boost. Organic options include fish emulsion, seaweed extract, or compost tea. Water the soil before fertilizing to avoid burning roots, and explore fertilizer to the soil, not the leaves.

Stop fertilizing about four weeks before your first expected frost. Late fertilizing pushes new growth that won't have time to mature and diverts energy from ripening existing fruit.

Watch for common pests and diseases

Hornworms are large green caterpillars that can strip a plant bare. Hand-pick them if you see them, or use spinosad (an organic insecticide) if the infestation is heavy. Aphids cluster on new growth and can be sprayed off with water or treated with insecticidal soap. Spider mites cause yellowing and fine webbing on leaves — they thrive in hot, dry conditions, so consistent watering and misting help prevent them.

Early blight appears as brown spots with concentric rings on lower leaves and spreads upward as the season progresses. Remove affected leaves and improve air circulation by pruning lower branches. Powdery mildew looks like a white coating on leaves and thrives in humid conditions — water at soil level only, space plants for air flow, and remove heavily affected leaves. Blossom end rot (a dark sunken spot on the fruit) is caused by inconsistent watering and calcium deficiency — maintain steady soil moisture and avoid over-fertilizing with nitrogen.

The best defense against disease is prevention: space plants for air flow, water at soil level, remove lower leaves as plants grow, and clean up fallen leaves and debris. If problems develop, address them early before they spread.

Frequently Asked Questions

Can I grow tomatoes in containers?

Yes. Use a pot at least five gallons for determinate varieties and ten gallons or larger for indeterminate types. Fill with potting mix, not garden soil. Container tomatoes dry out faster than in-ground plants, so check soil moisture daily and water more frequently. They still need six to eight hours of direct sunlight and the same fertilizing schedule.

Should I prune tomato plants?

Determinate varieties need little pruning. Indeterminate varieties benefit from removing lower leaves (up to the first flower cluster) once the plant is established, which improves air flow and reduces disease. Some growers remove suckers (shoots that grow between the main stem and branches) on indeterminate types to focus energy on fewer, larger fruits, but this is optional and reduces total yield slightly.

When do I harvest tomatoes?

Pick tomatoes when they reach full color — they don't need to be rock-hard. Tomatoes picked at the breaker stage (when they first show color) will ripen indoors at room temperature. Harvesting regularly encourages the plant to produce more flowers and fruit throughout the season.

Why are my tomato flowers dropping without setting fruit?

Flowers drop when nighttime temperatures drop below 55 degrees Fahrenheit or exceed 75 degrees, when soil is too dry or too wet, or when plants are over-fertilized with nitrogen. Maintain consistent watering, avoid excessive nitrogen, and wait for temperatures to stabilize. Once conditions improve, new flowers will set fruit.

Can I save seeds from my tomatoes for next year?

Yes, but only from heirloom or open-pollinated varieties. Hybrid tomatoes won't produce seeds that grow into plants identical to the parent. Scoop seeds and gel into a jar, ferment for two to three days to remove the gel coating, rinse, dry completely on a plate, and store in a cool, dry place. Seeds stay viable for three to four years.