Start with seeds or seedlings, depending on your timeline and space
You can grow tomatoes from seed indoors six to eight weeks before your last frost date, or buy seedlings from a garden centre and plant them directly outside after frost danger passes. Seeds take longer but cost less and give you more variety choices. Seedlings are faster — you can harvest fruit within two to three months of planting — and work better if you have limited indoor space or no grow lights.
If you choose seeds, plant them in seed-starting mix in small containers under a light source (a sunny window works, but a basic shop light is more reliable). Keep the soil moist but not waterlogged. Seedlings should sprout in five to ten days and be ready to transplant into larger pots after they develop their first true leaves — the second set that looks like actual tomato leaves, not the smooth seed leaves.
Seedlings need six to eight hours of light daily and temperatures between 65 and 75 degrees Fahrenheit. If you are using a window, rotate the containers every few days so they grow straight instead of leaning toward the light.
Key Takeaways
- Tomatoes need at least six to eight hours of direct sunlight daily and soil that drains well but stays consistently moist, not soggy.
- Plant seedlings outside only after your last frost date has passed, and harden them off by gradually exposing them to outdoor conditions over seven to ten days.
- Determinate varieties (bush types) stop growing at a set height and produce most fruit at once; indeterminate varieties (vining types) grow continuously and produce fruit until frost.
- Stake or cage your plants early to prevent root damage later, and remove lower leaves once the plant is established to reduce disease.
- Water deeply and at soil level rather than from above, and harvest fruit when it reaches full colour but is still slightly firm.
Choose a location with full sun and prepare the soil
Tomatoes need six to eight hours of direct sunlight daily — more is better. A south-facing spot works well in most climates. If you live somewhere very hot, afternoon shade can prevent fruit from sunscald, but morning sun is essential.
Soil should drain well but hold moisture. Mix compost or aged manure into the top six to eight inches of garden soil before planting. If you are using containers, fill them with potting mix (not garden soil, which compacts in pots). A five-gallon container is the minimum for a determinate variety; indeterminate types need ten gallons or more because they grow taller and produce longer.
Test your soil pH if possible — tomatoes prefer slightly acidic soil between 6.0 and 6.8. If your soil is very alkaline or acidic, amending it before planting saves trouble later. You can get a straightforward test kit from any garden centre.
Harden off seedlings and plant at the right depth
Before moving seedlings outside permanently, expose them to outdoor conditions gradually over seven to ten days. Start with two hours in a sheltered spot, then increase time and exposure to wind and sun each day. This toughens the plants so they do not wilt or stop growing when transplanted.
Plant seedlings outside only after your last frost date has passed and soil has warmed to at least 60 degrees Fahrenheit. Bury the stem deeper than it was growing in the pot — tomatoes develop roots all along the buried stem, which strengthens the plant. You can bury up to the first true leaves if the seedling is leggy (tall and thin).
Space determinate varieties 24 to 36 inches apart and indeterminate varieties 36 to 48 inches apart. Crowding reduces air circulation and increases disease risk.
Support the plant with stakes or cages early
Install support structures at planting time, not later. Driving a stake or cage into the soil after roots have spread damages them and stresses the plant. A straightforward wooden stake or metal cage both work — choose based on your space and how tall the variety grows.
For indeterminate varieties that grow six feet or taller, a sturdy stake or string trellis is better than a cage, because cages often collapse under the weight of fruit. Tie the main stem loosely to the stake with soft material like cloth strips or plant tape, leaving room for the stem to thicken as it grows.
Determinate varieties stay compact and work well in cages. Whichever you choose, the goal is to keep fruit off the ground and improve air circulation around the leaves.
Water consistently and remove lower leaves as the plant grows
Water deeply at soil level rather than from above — wet leaves invite fungal disease. Tomatoes need about one to two inches of water per week, depending on temperature and rainfall. In hot weather, you may need to water every two to three days. Let the top inch of soil dry slightly between waterings, but never let the plant wilt.
Once the plant is established and flowering, remove leaves from the bottom six to twelve inches of the stem. This improves air circulation, reduces disease, and directs energy toward fruit rather than excess foliage. Continue removing lower leaves throughout the season as the plant grows taller.
Mulch around the base with two to three inches of compost or straw to keep soil temperature steady, reduce watering frequency, and prevent soil-borne disease from splashing onto leaves during rain.
Fertilize regularly once flowering begins
Tomatoes are heavy feeders. If you mixed compost into the soil at planting, the plant has nutrients to start with, but you need to feed it once flowers appear. Use a balanced fertilizer (like 10-10-10) or a tomato-specific formula every two to three weeks, following the package directions for your container or garden size.
Too much nitrogen produces lots of leaves but few flowers and fruit. If your plant is leafy but not flowering, switch to a fertilizer higher in phosphorus and potassium (the second and third numbers on the package).
Calcium deficiency causes blossom-end rot — dark, sunken spots on the bottom of fruit. If you see this, add crushed eggshells or a calcium supplement to the soil and water consistently to prevent it from worsening on new fruit.
Harvest fruit when it reaches full colour
Tomatoes continue to ripen after picking, so you can harvest them when they reach full colour but are still slightly firm. This is especially useful if pests or disease threaten the plant — picking early saves the crop. Fruit picked at the "breaker stage" (when the first blush of colour appears) will ripen indoors in three to five days at room temperature.
Indeterminate varieties produce fruit continuously until frost, so you can harvest throughout the season. Determinate varieties produce most fruit within a short window, usually four to six weeks, so you get a large harvest all at once — useful if you plan to preserve or can the tomatoes.
Store ripe tomatoes at room temperature, not in the refrigerator, which damages flavour and texture. Use them within a few days of ripening for best taste.
Frequently Asked Questions
What is the difference between determinate and indeterminate tomatoes?
Determinate varieties grow to a set height (usually three to four feet), stop growing, and produce most fruit within a short window. Indeterminate varieties grow continuously throughout the season, reaching six feet or taller, and produce fruit until frost. Choose determinate if you want one large harvest; choose indeterminate if you want fresh tomatoes all summer.
Why are my tomato leaves turning yellow?
Yellow lower leaves are normal as the plant matures — remove them. Yellow leaves higher up can mean nitrogen deficiency (feed the plant), inconsistent watering (water deeply and regularly), or fungal disease (improve air circulation and remove affected leaves). If yellowing spreads quickly, take a photo to a local garden centre for diagnosis.
Can I grow tomatoes in a pot on a balcony?
Yes, if the balcony gets at least six to eight hours of direct sun. Use a pot at least five gallons for determinate varieties and ten gallons for indeterminate types. Containers dry out faster than garden soil, so check moisture daily in hot weather. Wind on a balcony can dry plants quickly and stress stems, so stake or cage them securely.
What should I do with green tomatoes at the end of the season?
Pick them before the first frost and ripen them indoors at room temperature, away from direct sunlight. They will turn colour over one to three weeks. You can also make fried green tomatoes or green tomato jam with unripe fruit. Tomatoes picked after frost has killed the plant will not ripen further.
How do I prevent pests and disease?
Remove lower leaves to improve air circulation, water at soil level only, and space plants far enough apart for air to move around them. Inspect plants weekly for insects or spots on leaves. Pinch off affected leaves early. Neem oil or insecticidal soap work for many common pests. Rotate where you plant tomatoes each year to reduce soil-borne disease.