grow Lettuce in a Greenhouse

How to grow Lettuce in a Greenhouse?

Feel free to know how to Grow Lettuce in a Greenhouse. Grow lettuce year-round with proper greenhouse care. Sow seeds shallowly, ensure sunlight, and manage temperature between 45-55°F.

Harvest young leaves for tenderness. Combat pests and provide consistent watering. Top varieties like Winter Density and Austral offer versatility. With succession planting, enjoy a steady lettuce supply.


How to grow lettuce in a greenhouse?

How to grow lettuce in a greenhouse

Sow lettuce seeds anytime when the greenhouse temperature (and soil) stays between 40-85°F for germination. Avoid freezing temperatures but also be cautious of excessive heat, as it’s not ideal for lettuce growth.

Start planting lettuce outdoors

When planting lettuce, sow seeds every 8-16 inches in rows 12 inches apart or broadcast them and thin later.

The spacing varies based on lettuce type: loose leaf or baby lettuce prefers 4-8 inches apart, while loose-headed and firm-headed varieties thrive at 8 inches and 16 inches apart, respectively.

When growing lettuce in pots or seed trays

Sprinkle lettuce seeds on top of soil in a container or tray, cover with a shallow layer of fine soil, and gently press down.

 Keep the seeds near the surface as they need light to germinate. Water gently, preferably with a mist setting.

Maintain soil temperature between 65-70°F for optimal germination; use a seedling heat mat or greenhouse heater if needed in cooler temperatures.

Top Lettuce Varieties for Production in Greenhouses

Top Lettuce Varieties for Production in Greenhouses

Lettuce thrives in greenhouse gardening, excelling in spring, fall, and mild winter climates with added warmth. With numerous types and varieties available, here are some top picks for greenhouse growing.

Winter Density Lettuce:

Combines romaine texture with butterhead sweetness. Frost-tolerant variety. Available for purchase from High Mowing.

Australe Lettuce:

 Stunning and delicious butterhead (or bib) variety. Purchase available from High Mowing.

Sulu Baby Leaf Lettuce:

Quick-growing, ready to harvest in 29 days. Ideal for fresh salads. Available for purchase from High Mowing.

Red Salad Bowl Lettuce:

 Fast-growing red oak leaf variety, resistant to bolting. Perfect for fall greenhouse cultivation. Available for purchase from High Mowing.

Growing lettuce: All you need to know

Lettuce grows quickly, ready for harvest in just one month. However, it can bolt if temperatures rise, even in winter. Maintain ideal growing conditions for a perfect crop.

The Ideal Greenhouse Temperature for Growing Lettuce

Maintain greenhouse temperature between 50-70°F during the day. On warmer days, keep soil moist and ensure ample ventilation to prevent stress on lettuce. Night-time temperatures of 45-55°F are optimal. Lettuce can withstand short cold spells down to 35°F, but protect from hard freezes using insulation or heaters.

How much water is necessary to grow lettuce in your greenhouse?

Water lettuce consistently throughout its growth stages. During germination, lightly mist the seeding tray to keep the soil moist but not waterlogged.

Use a misting system for automatic watering to avoid excess moisture. Provide about an inch of water per week.

 After transplanting, sprinkle seedlings with a light seaweed or fish emulsion solution. Lettuce, being shallow-rooted and fast-growing, needs constant access to water for tender, juicy leaves.

Typical Issues in Growing Lettuce

Common lettuce problems include earwigs, cutworms, and aphids. Woodchucks and rabbits can also pose a threat, but keeping greenhouse doors and lower windows closed can prevent their entry.

Harvest lettuce leaves when full-sized but still young to avoid bitterness and woodiness. Watch for signs of rot, especially from overwatering, and adjust watering accordingly. Use shade cloth before summer to delay bolting and extend the harvest period.

Similarly, You should read about how to Grow Asparagus In A Greenhouse?

Tricks and Tips on how to grow lettuce in a greenhouse

  • Successive sowing ensures a continuous lettuce harvest.
  • For year-round growth, consider artificial heating or cooling in your greenhouse.
  • Use ventilation systems to regulate temperature and prevent overheating.
  • Protect lettuce from extreme cold with insulation or cloches if temperatures drop below freezing.
  • Plant garlic or chives nearby to manage aphids.

Harvest Lettuce

  • Harvest lettuce before full maturity for optimal tenderness, ideally in the early morning before sun exposure.
  • With romaine and butterhead varieties, you have two options: either cut the entire head at the base or pluck off the outer leaves.
  • Continuously harvesting outer leaves enables prolonged harvesting from a single plant.
  • For baby-leaf lettuce, use a knife to cut, leaving new growth to regrow (cut and come again). Use harvested leaves immediately or refrigerate for up to 10 days.

FAQs(Frequently Asked Questions)

Does a greenhouse deliver excellent lettuce growth?

Growing lettuce in a hydroponic greenhouse is simple: It’s easy with short crop cycles and low labor needs. You can grow it all year round. The process is like a factory, producing top-quality lettuce consistently.

How is lettuce grown in a greenhouse without heat?

In fact, keep night temperatures ideally between 45-55°F.It can handle short cold spells down to 35°F, especially in a greenhouse .Protect lettuce from hard freezes with insulation or heaters if needed.

Is it possible to grow lettuce year-round?

A “Butterhead” form of lettuce is available year-round. It has creamy, compact, and crisp white hearts encircled by delicious, juicy, textured green leaves.

As its name suggests, it may be harvested year-round if given proper shelter throughout colder months.

Seeds can be planted from the beginning of spring to late summer. Write this material in a clear, concise, and descriptive manner.


After reading the entire article, get complete knowledge how to grow lettuce in a greenhouse. With optimal care and suitable varieties like Winter Density and Austral, enjoy a continuous harvest.

Tackle common issues like pests and temperature fluctuations with strategic measures. With proper planning and execution, relish the satisfaction of homegrown, flavorful lettuce straight from your greenhouse.