How to Grow Tomato

Choosing the Right Variety

Tomatoes come in two growth habits, and the difference will shape how you plan your bed. Determinate (bush) varieties grow to a fixed height, set all their fruit in a concentrated window, then stop. Good for canning and small spaces. Indeterminate (vining) types keep growing and producing fruit until frost kills them. Most heirloom slicers and cherry tomatoes are indeterminate.

Beyond growth habit, pick varieties that match what you want from your harvest. Cherry and grape tomatoes (Sun Gold, Sweet 100, Juliet) are the easiest to grow and produce reliably even in tough seasons. Slicers (Better Boy, Celebrity, Early Girl) give you the classic sandwich tomato. Beefsteaks (Brandywine, Cherokee Purple, Mortgage Lifter) produce the largest fruit with complex flavor, but take longer and demand more patience. Paste tomatoes (San Marzano, Roma, Amish Paste) have dense, low-moisture flesh ideal for sauces and canning.

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Starting from Seed

Start tomato seeds indoors 6–8 weeks before your last frost date. Plant seeds ¼" deep in a sterile seed-starting mix, keep the soil consistently moist (not soggy), and maintain temperatures of 70–80°F. Seeds germinate in 6–14 days. Once sprouts appear, they need strong light: at least 14–16 hours daily under grow lights, or a bright south-facing window.

When seedlings develop their first set of true leaves (the second pair, with serrated edges), transplant them into individual 3–4" pots. Bury the stems up to the lowest leaves — tomatoes form adventitious roots along buried stems, which builds a stronger root system.

Harden off seedlings for 7–10 days before transplanting outdoors. Start with 1–2 hours of outdoor shade, gradually increasing exposure to direct sunlight and wind each day.

Transplanting & Spacing

Transplant after all danger of frost has passed and nighttime temperatures stay consistently above 50°F. In square foot gardening, each tomato gets one full square foot. They need the space. Plant them deep: bury two-thirds of the stem. The buried portion will develop roots, giving the plant a much stronger root system from day one.

Place tall varieties on the north side of your bed so they don’t shade shorter crops. Tomatoes pair well with basil (plant it in the adjacent square), which may repel aphids and whiteflies.

Support & Training

Every tomato plant needs support. Without it, fruit rests on soil and rots. Your options:

• Cages: the easiest approach. Use sturdy 5-foot concrete reinforcing wire cages (not the flimsy cone-shaped ones from hardware stores). One cage per plant, set at transplanting time.
• Stakes: drive a 6-foot stake 12" into the soil beside each plant. Tie the main stem loosely with soft cloth or garden twine as it grows.
• Florida weave: best for rows. Run twine between end stakes, weaving between plants on alternating sides. Add a new level of twine every 8–10" of growth.

For indeterminate varieties, prune suckers (the shoots that grow in the crotch between the main stem and a branch). Removing suckers below the first flower cluster directs energy into fruit production. Above the first cluster, you can leave some suckers for extra yield.

Watering & Feeding

Tomatoes need deep, consistent watering: about 1–2" per week. Water at the base of the plant, never overhead, to prevent foliar diseases. Mulch heavily (3–4" of straw or shredded leaves) to maintain soil moisture and keep roots cool.

Fertilize at transplanting with a balanced or phosphorus-heavy starter fertilizer. Once fruit begins to set, side-dress every 3–4 weeks with compost or a balanced organic fertilizer. Tomatoes are heavy feeders, but too much nitrogen produces lush foliage at the expense of fruit.

Common Problems

Blossom End Rot

Dark, sunken spots on the bottom of the fruit. This is a calcium uptake issue caused by inconsistent watering in the vast majority of cases — not a lack of calcium in the soil. Mulch heavily and water on a schedule. In rare cases, very acidic soil (pH below 5.5) or heavy ammonium-nitrogen fertilization can also block calcium uptake even with consistent moisture.

Early Blight

Brown spots with concentric rings on lower leaves, progressing upward. Remove affected leaves promptly, improve air circulation by pruning lower branches, and mulch to prevent soil splash. Resistant varieties (Celebrity, Mountain Magic) help.

Cracking

Heavy rain after a dry spell causes fruit to absorb water faster than the skin can expand. Consistent watering and mulching prevent this. Harvest mature fruit before expected storms when possible.

Hornworms

Large green caterpillars that can strip a plant overnight. Hand-pick them (they’re large enough to spot easily). If you see a hornworm covered in small white projections, leave it alone. Those are braconid wasp cocoons — the larvae have already fed on the hornworm internally and are pupating on its surface. The hornworm is doomed, and the emerging wasps will parasitize more hornworms in your garden.

Late Blight

Unlike early blight, late blight is fast-moving and can destroy an entire plant in days. Symptoms: large, dark, water-soaked patches on leaves and stems, often with white mold on the underside in humid conditions. Remove affected plants immediately. Do not compost them. Copper-based fungicides applied preventively can help in regions where late blight is common.

Blossom Drop

Flowers fall off without setting fruit. This usually happens when nighttime temperatures drop below 55°F or rise above 75°F, disrupting pollination. High humidity and excessive nitrogen also contribute. It’s temporary. Fruit set resumes once temperatures moderate.

Harvesting

Pick tomatoes when they are fully colored and slightly soft to the touch. They’ll continue to ripen off the vine. Cherry tomatoes should come off easily with a gentle twist; slicers can be cut with a stem stub attached.

Never refrigerate fresh tomatoes. Cold temperatures destroy volatile flavor compounds. Store at room temperature, stem-side down. If you have more than you can eat, tomatoes freeze well: just wash, core, and freeze whole in bags. The skins slip off after thawing.

At the end of the season, when frost threatens, pick all remaining fruit, including green tomatoes. Wrap green ones individually in newspaper and store in a cool, dark place. They’ll ripen slowly over 2–4 weeks. Or slice green tomatoes, bread, and fry them.

Frequently Asked Questions

How much water do tomatoes need per week?

Tomatoes need 1–2 inches of water per week, delivered at the base of the plant. In hot weather (above 90°F) or windy conditions, they may need more. The key is consistency. A deep soak every few days beats light daily watering, which encourages shallow roots.

What causes blossom end rot on tomatoes?

Blossom end rot looks like calcium deficiency, but it’s almost always a water problem. When soil moisture swings between dry and saturated, roots can’t absorb calcium fast enough to feed developing fruit. Consistent moisture and mulch fix it, not calcium sprays.

When should I start tomato seeds indoors?

Start tomato seeds indoors 6–8 weeks before your last frost date. Plant seeds ¼ inch deep in sterile seed-starting mix at 70–80°F. Seeds germinate in 6–14 days.

How many tomato plants per square foot?

One tomato plant per square foot. Tomatoes are large plants that need the full 12×12 inch square for root spread and airflow. Place tall varieties on the north side of the bed.

Should I prune tomato suckers?

For indeterminate varieties, remove suckers below the first flower cluster to direct energy into fruit production. Above the first cluster, you can leave some suckers for extra yield. Determinate varieties should not have suckers removed (they fruit on branch tips, so removing suckers reduces yield), but stripping lower leaves below the first fruit cluster still helps with airflow and blight prevention.