Greenhouse Tomatoes - Key Growing Information
CULTURE: Tomatoes thrive in a tunnel or greenhouse environment, which increases your control over fruit quality and extends the harvest season, both early and late. Growing info is similar to field tomatoes, but transplants are typically started earlier and may need additional development time (6–7 weeks) and supplemental lighting to maintain strong seedlings.
TRANSPLANTING INDOORS: Provide 4–6 sq.ft. growing area per leader depending on variety, climate, disease pressure, and pruning methods. Plant deeply like field tomatoes unless grafted, in which case, plant with union above soil. For 5–7 days after transplanting, maintain 73–77°F (23–25°C) day and night temperature to promote rapid foliar and root growth. At fruit set, lower night temps to 62–66°F (17–19°C) and begin monitoring plants to manage them towards season-long productivity.
TRELLISING/PRUNING: Train plants to 1–2 branchless leaders onto separate vertical strings with trellis clips roughly 1" below every third leaf. Keep taut and reuse bottom clips, keeping at least 3–4 per string. Consider a lower-and-lean system if you have a long season, capable structure, and enough labor. Pruning leaves and clusters can help to manage diseases and steer towards maximum production. Keep grafted plants free from scion roots and rootstock suckers.
DISEASES & INSECT PESTS: A slightly different set of pests attack indoor crops than outdoor crops, but similar management strategies apply. The use of beneficial insects and grafting is generally more successful in tunnels/greenhouses than open field.
HARVEST/STORAGE: Same as field, plus potential for truss harvesting.
DAYS TO MATURITY: From transplanting.
TRANSPLANTS: Avg. 950 plants/1,000 seeds.
SEED SPECS: Avg. 11,000–13,000 seeds/oz.
PACKET: 15 seeds, plants about 20 feet.