Plant care

Tomato care

Solanum lycopersicum

Also called garden tomato.

Light

Tomato is a sun-lover and needs the brightest spot in the home to thrive. 6-8 hours of direct sun daily. Less than 6 hours produces leggy plants with poor fruit set. Indoors that almost always means a south or west-facing windowsill in the northern hemisphere. Plants moved abruptly from low light to direct sun will scorch — acclimate them over 7-10 days by giving a little more sun each day.

Watering

Outdoor tomato crops want deep watering 2-3 times per week, more in heat. The single best habit is a finger-test before watering — push a finger 3-4 cm into the soil. If it comes back damp, wait a day. If it comes back dust-dry, water deeply at the base of the plant. Aim for 2-3 cm of water per week as a few deep soaks rather than daily sips. Mulch heavily to even out moisture and reduce blossom-end rot.

Soil and pot

Tomato grows best in rich, well-drained loam. Compost-amended garden soil or a deep container mix. pH 6.0-6.8 is ideal. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Tomato sits happiest at around 40-70% (outdoor) humidity and 18-29°C (65-85°F). Outdoor humidity rarely matters; greenhouse growers ventilate to prevent disease. If you keep the room above 18 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed tomato sparingly. Balanced feed at planting; switch to a higher-potassium feed (tomato food) once flowering starts. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on tomato in the Growli community. Where a problem matches one of our diagnostic guides, click through for the full step-by-step recovery plan written for tomato specifically.

Yellow lower leaves — Early blight, nitrogen depletion, or natural senescence.
Curling leaves — Heat stress, herbicide drift, or a tomato virus.
Brown spots on leaves — Early blight or septoria leaf spot.
Blossom-end rot — Inconsistent watering, not a calcium deficiency. Mulch and water deeply.
Cracking fruit — Sudden water swings after dry spells; mulch helps.

Companion plants

Tomato pairs well with Basil, Marigold, Onion, and Carrot. These are species with similar light and water needs, so you can grow them in the same bed or container without conflict.

Propagation

Sow seed indoors 6-8 weeks before the last spring frost; transplant out after nights stay above 10°C. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Tomato is mildly toxic to pets. ASPCA lists tomato foliage and unripe fruit as toxic to cats, dogs and horses due to solanine. The ripe fruit is safe. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Tomato care — frequently asked questions

What is Tomato?

Tomato (Solanum lycopersicum) is a edible crop with a determinate (bush) or indeterminate (vine) annual growth habit, reaching 60 cm bush types, 1.5-2 m+ vine types at maturity. Tomato is a warm-season fruiting crop from the Andes, the cornerstone of the home vegetable garden. It needs 6-8 hours of direct sun, consistent water, and steady feeding to set heavy fruit.

How much light does tomato need?

Tomato grows best in direct sun (at least 4-6 hours). 6-8 hours of direct sun daily. Less than 6 hours produces leggy plants with poor fruit set.

How often should I water tomato?

Water tomato deep watering 2-3 times per week, more in heat. Aim for 2-3 cm of water per week as a few deep soaks rather than daily sips. Mulch heavily to even out moisture and reduce blossom-end rot. The finger-test (or lifting the pot to feel its weight) beats a fixed weekly calendar because pot size, light, and season all change how fast the soil dries.

Is tomato toxic to cats and dogs?

Tomato is mildly toxic to pets. ASPCA lists tomato foliage and unripe fruit as toxic to cats, dogs and horses due to solanine. The ripe fruit is safe.

What USDA hardiness zone does tomato grow in?

Tomato is rated for USDA zone Grown as an annual in zones 3-11 and RHS hardiness H1c (tender; outdoors only in summer). Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Tomato deep-dive guides

Every aspect of tomato care, each with its own calibrated guide:

Related guides

Tomato is also commonly called garden tomato.