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Year-Round Greenhouse: What to Grow Each Season
Winter growing is a light problem before it is a heat problem. Plan crops around the shortest day, not the coldest.
Direct answer: A year-round greenhouse runs four different crops: seedlings in spring, heat-lovers in summer, storage and salad in autumn, and hardy greens in winter. Winter production depends more on day length than temperature — below about 10 hours of daylight, most crops simply stop growing, no matter how warm it is.
Season-by-season table
| Season | Sow | Harvest | Job |
|---|---|---|---|
| Spring | Tomatoes, peppers, eggplant, brassicas | Overwintered greens, radish | Ventilation, hardening off |
| Summer | Succession salad, beans | Tomatoes, cucumbers, peppers | Shade cloth, maximum airflow |
| Autumn | Spinach, mache, claytonia, garlic | Late tomatoes, peppers | Remove spent crops, add compost |
| Winter | Nothing (or microgreens indoors) | Hardy greens, leeks, carrots | Insulate, ventilate on sunny days |
Winter greens
Spinach, mache (corn salad), claytonia, kale, and winter lettuce survive low light and cold better than anything else. Sow in late summer to early autumn so plants are established before days shorten. Growth slows to near zero in December and January; you are harvesting what grew in October, not what is growing now.
Summer heat management
A closed greenhouse in July can hit 120°F and cook everything. Use shade cloth (30–50%), open vents and doors early, and consider a ridge vent. Tomatoes set fruit poorly above 90°F, so afternoon shade actually improves yield in hot climates.
Frequently asked questions
Can I grow tomatoes in winter?
Only with supplemental heat and light, which makes them expensive. Hardy greens are the realistic winter crop.
What is the minimum temperature for winter greens?
Most survive 25–30°F inside a protected greenhouse. Below that, add a row cover over the plants as a second layer.
Do I need to water in winter?
Yes, but much less. Water in the morning on sunny days so foliage dries before night.
See the self-heating greenhouse guide for structure and thermal mass for night heat.
Frequently asked questions
Can I grow tomatoes in winter?
Only with supplemental heat and light, which makes them expensive. Hardy greens are the realistic winter crop.
What is the minimum temperature for winter greens?
Most survive 25–30°F inside a protected greenhouse. Below that, add row cover as a second layer.
Do I need to water in winter?
Yes, but much less. Water in the morning on sunny days so foliage dries before night.