key growing information

Growing Peppers in a Greenhouse: Sowing, Care & Harvest

How to grow peppers in a greenhouse: raising transplants, temperatures, feeding, plant and stem density, pruning and trellising, pest control and harvest.

By Hensley’s Seed Co. September 3, 2026

Greenhouse Peppers - Key Growing Information

Greenhouse peppers, grown on hanging trellises in greenhouse trials.

SCIENTIFIC NAME:

Capsicum annuum

CULTURE:

Sow 6–8 weeks before transplanting, keeping the soil at a steady 80–90°F (27–32°C). As soon as the first true leaves appear, move seedlings into cell-type containers or soil blocks. Containers 2" or larger build bigger, stronger roots; 4" blocks are standard. Grow at 70–74°F (21–23°C) by day and 68°F (20°C) at night, feeding as needed with a complete nutrient solution (EC 1.5–2, pH 5.2) or similar to keep plants deep green. For the first week in the greenhouse, aim for about 73–74°F (23°C) by day and 69–70°F (21°C) at night to encourage fast leafy growth and rooting. After 7–10 days, lower nights to 64–68°F (18–20°C) and keep days at 70–75°F (21–24°C). For two-stem plants, use 3–3½ plants per square meter (9 sq. ft.) for 6–7 stems per square meter. You can prune to 4 stems at the same stem density, but fruit will be smaller. Remove flowers up to the second or third node above the first branch so plants grow large enough before carrying fruit.

TRELLISING:

Prune to 2–4 stems and train them up strings as with greenhouse tomatoes.

HARVEST:

Pick once fruit shows 80% or more of its mature color.

DISEASES AND PESTS:

Rotate crops or use fresh growing media to reduce soilborne disease. Releasing beneficial insects on a regular schedule helps keep pests in check.

DAYS TO MATURITY:

From transplanting.

SEED SPECS:

About 3,200–4,150 seeds per oz. (average 3,700).

TRANSPLANTS:

About 950 transplants per 1,000 seeds.

MINI:

10 seeds.

PACKET:

25 seeds per packet unless noted.