Germination temperature
24-29 °C (75-85 °F); no germination below about 10 °C (50 °F).

Vegetable growing guide
Start seedlings warm and bright, harden them gradually, then transplant after frost when the soil has warmed. Tomato seed sprouts in about six days at 25-30 °C.
24-29 °C (75-85 °F); no germination below about 10 °C (50 °F).
About 6 mm (1/4 in).
About 6 days at 25-30 °C; 2 weeks at 15 °C.
Seed is covered; strong overhead light from emergence.
No soaking needed; biocontrol seed treatment helps in the tropics.
Transplant at 25 days (tropics) to 5-6 weeks (indoors).
Use clean containers and sterile soilless germination mix. Check the packet for growth habit (bush or vining), days to maturity and disease-resistance codes. In India TNAU treats seed 24 hours before sowing with Trichoderma viride (4 g per kg) or Pseudomonas fluorescens (10 g per kg) against damping off.
Not needed. Tomato seed takes up water readily.
Not needed. Tomato is a warm-season crop and needs no cold treatment.
Not needed. Steady warmth and moisture after sowing matter far more.
Keep the mix at 24-29 °C (75-85 °F) until emergence, using a heat mat if needed, then about 21 °C (70 °F) after emergence. Seed fails below about 10 °C (50 °F) and above 35 °C (95 °F). In Tamil Nadu TNAU sows in May-June and November-December.
About 6 mm (1/4 in) deep in moist germination mix. In nursery beds TNAU sows in lines 10 cm (4 in) apart and covers the seed with sand.
Sterile, soilless seed mix in trays or cells. Commercial nurseries in India sow one seed per cell in 98-cell protrays.
Keep the mix moist but not waterlogged; heated trays dry faster, so check daily. Remove any cover once seedlings appear.
Give 12-16 hours of strong light daily from emergence, with grow lights 5-10 cm (2-4 in) above the seedlings. Windowsill light alone gives tall, weak plants.
About 6 days at 25-30 °C (77-86 °F), 8 days at 20 °C (68 °F) and 14 days at 15 °C (59 °F).
Thin or pot seedlings to about 5 cm (2 in) apart when true leaves appear. Indoors, start about five to six weeks before the intended outdoor planting date; in the Indian plains TNAU transplants nursery seedlings at 25 days.
Over one to two weeks, expose seedlings to more outdoor sun and wind, starting with a few hours in a sheltered spot, while protecting them from freezing temperatures.
Plant outdoors after frost danger has passed and the soil has warmed. Bury the stem in a trench 8-10 cm (3-4 in) deep up to the lowest leaves, space vining types 60-90 cm (2-3 ft) apart (TNAU: 60 x 45 cm) and install stakes or cages at planting. Water on day 3 after planting, then weekly.
Cause: cold mix. Fix: keep it at 24-29 °C (75-85 °F); at 10 °C (50 °F) emergence takes about six weeks.
Cause: too little light or starting too early. Fix: use grow lights close to the plants for 12-16 hours a day and sow only 5-6 weeks before planting out.
Cause: damping off in cool, wet mix. Fix: sterile mix, bottom heat, biocontrol seed treatment and careful watering.
Cause: blossom end rot from uneven soil moisture. Fix: water regularly, about 2.5 cm (1 in) a week, and mulch.
Cause: tomato leaf curl virus spread by whiteflies. Fix: grow resistant hybrids; TNAU lists COTH 2 and TNAU Tomato Hybrid CO 3.
Bush and vining tomatoes grow differently. Bush types stay 60-75 cm (24-30 in) tall and ripen over 4-6 weeks; vining types reach 1-1.5 m (3-5 ft) or more and fruit until cold weather. TNAU stakes hybrids 30 days after planting and removes side shoots up to 20 cm above the ground.
Avoid beds where tomatoes, potatoes, peppers or eggplants grew in the past 3-4 years. TNAU solarizes nursery soil against Fusarium wilt.
Apply organic mulch 8-10 cm (3-4 in) deep and check with a trowel that water has reached the root zone. Sudden heavy rain after dry weather causes cracked fruit.
Aim for soil pH 5.5-7.0. Side-dress with nitrogen when the first fruits enlarge, not earlier, to avoid leafy plants with little fruit.
Start tomato seeds warm and bright for sturdy transplants and a long harvest.
In climates with a short warm season, starting indoors is usually more reliable. Direct sowing is practical only where the frost-free season and soil warmth are sufficient; even in India tomatoes are usually raised in a nursery and transplanted at about 25 days.
No. Pruning and support depend on whether the variety is determinate or indeterminate and on the growing system. Bush types need no staking or pruning.
About 6 days at 25-30 °C (77-86 °F) and about 2 weeks at 15 °C (59 °F). Below 10 °C (50 °F) they barely germinate.