Tomato Care: Sowing, Feeding & Disease Guide
Solanum lycopersicum
Tomatoes are heavy feeders that reward consistent water, full sun, and early pruning. Most failed crops trace back to one of four things: uneven watering, calcium deficiency, late blight, or planting out too early.
Sowing
Start indoors 6–8 weeks before your last frost. Bottom heat (21–24°C) speeds germination to 5–7 days. Pot up once true leaves appear; bury stem deep — tomatoes root from buried stem hairs.
Transplanting out
Wait until night temperatures stay above 10°C and soil is 15°C+. Harden off over 7 days. Plant deep (2/3 of the stem), 60–90 cm apart for indeterminate types.
Watering
Deep, even watering at the base — 2–4 cm per week, more in heat. Uneven watering causes cracking and blossom end rot. Mulch heavily to buffer.
Feeding
Balanced feed at planting, then switch to high-potassium (tomato feed) once the first truss sets fruit. Weekly feeds during heavy fruiting.
Staking & pruning
Stake or cage immediately. For indeterminates, pinch out side-shoots in leaf axils weekly and top the main stem above the 5th–6th truss in short seasons.
Leaves and stems are toxic to pets (solanine). Fruit is fine for humans; green/unripe fruit causes stomach upset in some.
Frequently asked questions
Why do my tomatoes have black bottoms?
Blossom end rot — calcium uptake failure caused by uneven watering, not low soil calcium. Mulch, water more evenly, never let the soil dry out completely.
When should I plant tomatoes outside?
When night temperatures are reliably above 10°C and soil is 15°C+ — typically 2 weeks after your last frost date.
Why are the leaves curling?
Heat or drought stress curls leaves upward; viral disease curls them downward and stunts growth. The first resolves with watering; the second means pulling the plant.
How do I prevent late blight?
Water at the base only (never the foliage), space plants for airflow, remove lower leaves once fruit sets, and rotate crops — don't plant tomatoes where potatoes or tomatoes grew last year.
Track your Tomato in PlantbookOS
Adaptive reminders learn your plant's actual dry-down rate in your home — not a generic schedule. Log waterings by voice, snap photos to track growth, and ask FloraAI when something looks off.