How to Grow Hothouse Tomatoes for Off-Season Harvests

Overview

Greenhouse (hothouse) tomatoes extend the season for "out of season" freshness. South: plant summer for fall–spring harvest. North: plant winter for spring–fall harvest.

Growing Steps

Step 1: Start Seedlings

Poke drain holes in paper cups/milk cartons. Fill with moistened potting mix. Sow 3–4 seeds per container. Cover thinly. Check daily, water if dry. Germination in 7–10 days. Thin to one per container after first true leaves. Grow 5–6 weeks.

Step 2: Transplant to Large Containers

Add gravel layer to 5-gallon pots. Fill ⅔ with potting mix. Transplant 5–6 week seedlings. Fill around, water each.

Step 3: Water Daily

~2 quarts per plant daily or as needed.

Step 4: Fertilize Carefully

Use 5-10-10 fertilizer per package. Consider half-rate twice as often (NC State Extension) to avoid over-fertilization.

Step 5: Maintain Temperature

60–90°F for fruit set. Heater may be needed in winter.

Step 6: Provide Light

Several hours full sun daily. Supplement with artificial lights in winter.

Step 7: Support Plants

Add cage at ~10 inches tall. Eliminates pruning, conserves space, encourages upward growth. Tuck stray branches into cage.