Tomatoes are the crop most gardeners judge their whole season by, and for good reason: nothing from a shop tastes like a tomato picked warm from your own plant. They are also one of the most rewarding vegetables to grow, because a single healthy plant can keep you in fruit for months — provided you give it sun, support and steady water from the start.
This guide covers the whole season, from starting seeds indoors to the last harvest.
Tomatoes at a glance
| Growing factor | What tomatoes need |
|---|---|
| Sun | full sun |
| Soil pH | 6.0–6.8 |
| Days to germination | 7–14 |
| Days to maturity | 60–85 |
| Spacing | 24–36 inches |
| Water needs | high |
| Cold tolerance | tender |
| Family | Solanaceae |
Starting seeds
This is a start-indoors crop: sow under cover in trays, cells or small pots of seed compost, keep the mix moist but not waterlogged, and expect germination in 7–14 days. Give seedlings strong light from the moment they emerge.
Work backwards from your last frost date to time your sowing, using our seed-starting calculator and the frost-date calculator. Zones 11–13 are frost-free, so there the calendar is about heat and rain instead — check your local extension service for sowing windows that fit your area.
Tomato seed germinates readily indoors in warm conditions, and starting indoors is the standard approach because the plants need a long season. Sow in small pots or trays of seed compost, keep them somewhere warm and bright, and pot seedlings on into individual pots as they grow so they are sturdy, stocky plants by the time they go outside — leggy seedlings never quite catch up.
Transplanting and planting out
Tomatoes are planted out only once all danger of frost has passed and the soil has warmed up; a cold snap at this stage can set them back for weeks. Plant them deep — burying the stem up to the first true leaves encourages extra roots along the buried stem — and give each plant its full spacing, because crowded tomatoes mean poor airflow and more disease. Put supports in at planting time rather than later: a tall stake or a sturdy cage for each plant, tied loosely as it grows, saves you wrestling with a heavy, fruit-laden plant in midsummer.
Space plants 24–36 inches apart — crowding is one of the commonest causes of small harvests. Harden seedlings off for a week before planting out, and plant on a cloudy day or in the evening. Our plant-spacing calculator works out how many plants fit your bed.
Soil and feeding
Tomatoes grow best in rich, well-drained soil with plenty of organic matter. Dig in compost before planting: it improves heavy soil, helps light soil hold moisture, and feeds the soil life that feeds your plants. Aim for a soil pH of 6.0–6.8 — a simple soil test will tell you where you stand, and garden lime or sulfur can nudge pH up or down over a season, so test before you amend rather than guessing.
Feed lightly and steadily rather than in one heavy dose: too much fast nitrogen late in the season pushes leafy growth at the expense of the part you eat. Our fertiliser calculator works out amounts for your bed size, and the soil-volume calculator tells you how much mix a new bed needs.
Watering
Water needs are high, so this crop punishes neglect: keep the soil consistently moist — not waterlogged, but never allowed to dry right out. Deep, regular watering beats a light daily sprinkle, because it pulls roots down, and a thick mulch layer is almost essential.
Water at the base of the plant, in the morning, so the leaves dry quickly and the water reaches the roots. Our watering calculator gives a starting point for your bed size, and the watering schedule generator can build a routine around it. A mulch layer cuts evaporation and keeps moisture even.
Sunlight and temperature
Tomatoes need full sun — a spot that gets sun for most of the day. Our sunlight calculator can check your spot.
This crop is rated tender for cold tolerance, so frost will kill it: it needs warm soil and frost-free nights, and should only go outside once all danger of frost has passed. In Zones 11–13, which are frost-free, it can be grown for much of the year, though the hottest months may still stress it. Our hardiness-zone finder will confirm your zone, and the frost-date calculator gives you the frost dates to plan around.
Pests and diseases
The pests and diseases most often reported on tomatoes are aphids, tomato hornworm, whiteflies, cutworms, blight. Healthy, well-watered plants resist attack better than stressed ones, and rotating beds so the Solanaceae family does not repeat in the same spot helps keep soil-borne problems down.
- Aphids — small sap-sucking insects on new growth; wash off with a strong jet of water and encourage ladybirds.
- Tomato Hornworm — a large green caterpillar that strips leaves fast; hand-pick it, looking for its droppings on leaves below.
- Whiteflies — tiny white insects that rise in a cloud when disturbed; yellow sticky traps help monitor them.
- Cutworms — caterpillars that chew through young stems at soil level; a cardboard collar around each stem protects it.
- Blight — a fungal disease showing as dark spots on leaves, starting low and spreading in wet weather; water at the base and remove affected leaves.
Inspect plants weekly, especially leaf undersides, and act early. Our pest-identifier helper can help identify what you are seeing.
Companion plants
Good companion plants for tomatoes include:
- Basil — attracts pollinators
- Marigolds — their roots discourage some soil pests
- Carrots — use a different soil layer, so no competition
- Onions — their scent is said to confuse pests
- Parsley — attracts beneficial insects
Our companion-planting finder can suggest more pairings for your bed plan.
Harvesting
Pick tomatoes when they are fully coloured for their variety and give slightly when squeezed gently. Fruit left to ripen fully on the plant has the best flavour, so resist picking early unless the weather turns or pests are taking fruit. Pick regularly — every day or two in peak season — and the plant keeps producing. Green fruit left at the end of the season can be ripened indoors in a warm spot or used for chutney.
Expect the crop to be ready about 60–85 days after sowing, though weather and variety shift that window by a week or two either way. Our harvest-date calculator works out your expected harvest date from your sowing date, and the vegetable-yield estimator can estimate how much a bed should produce.
Common problems and fixes
| Problem | Likely cause | Fix |
|---|---|---|
| Blossom-end rot | uneven watering that disrupts calcium uptake | Keep the soil evenly moist with regular watering and a mulch layer, and avoid letting plants dry out and then flooding them. |
| Fruit cracking | a sudden flush of water after a dry spell | Water consistently rather than in bursts, mulch to even out soil moisture, and pick fruit as soon as it ripens so a rainstorm cannot split it.. |
| No fruit setting | temperatures too hot or too cold while flowers are open | Be patient: flowers often drop in a heatwave or a cold snap and set again when conditions ease. |
Blossom-end rot
Keep the soil evenly moist with regular watering and a mulch layer, and avoid letting plants dry out and then flooding them.
Fruit cracking
Water consistently rather than in bursts, mulch to even out soil moisture, and pick fruit as soon as it ripens so a rainstorm cannot split it..
No fruit setting
Be patient: flowers often drop in a heatwave or a cold snap and set again when conditions ease.
Frequently asked questions
When should I plant tomatoes?
Start seeds indoors before your last frost and plant out only after all frost danger has passed, since this is a tender crop. For zone-specific timing, see zone 5 or zone 7, and check your local extension service for the dates that fit your area.
How long do tomatoes take to grow?
Tomatoes take 60–85 days from sowing to maturity, and seed germinates in 7–14 days. Weather and variety shift the harvest window by a week or two, so judge readiness by look and feel rather than the calendar alone.
How far apart should I plant tomatoes?
Space plants 24–36 inches apart — that is the room a mature plant needs, and crowding means poor airflow and small harvests. Our plant-spacing calculator works out how many fit your bed.
Do tomatoes need pruning?
Most gardeners remove the side shoots that appear between the main stem and a leaf on tall, indeterminate varieties, which keeps the plant to one or two stems and lets light and air in. Bush or determinate varieties are usually left alone, since they fruit on many stems.