What Can I Grow in a Greenhouse Over Winter?

A greenhouse does not have to sit empty and idle once the temperature drops. In fact, winter is one of the most rewarding times to use one. Whether you have a modest backyard structure or a fully equipped growing space, a greenhouse gives you the power to extend your growing season well beyond what the outdoor elements would allow.

What Grows Best in an Unheated Greenhouse in Winter

An unheated greenhouse typically maintains temperatures a few degrees above the outdoor air, which is often enough to keep cold-hardy crops alive and slowly growing through winter. The golden rule here is to choose crops that tolerate near-freezing temperatures and do not require active growth to be useful. Many of these plants will grow slowly but will remain harvestable throughout the colder months.

Best Choices For Unheated Greenhouses:

• Lettuce and salad leaves
• Spinach
• Kale and Swiss chard
• Garlic and onion sets
• Broad beans (started in autumn)
• Radishes
• Winter-hardy herbs such as chives and parsley
• Overwintering flower seedlings

What Grows Best in a Heated Greenhouse in Winter

A heated greenhouse one maintained at a minimum of 7°C to 10°C dramatically expands your options. Understanding how to keep a greenhouse warm in the winter becomes essential at this stage, whether through insulation, thermal mass, or controlled heating systems. You can keep warm-season crops alive, start early seedlings for spring, and even harvest fruiting plants well into the coldest months. The trade-off is energy cost, so choosing high-value crops that justify the heating bill makes practical and financial sense.

Best Choices For Heated Greenhouses:

• Tomatoes (with supplemental lighting)
• Cucumbers
• Peppers and chillies
• Basil and coriander
• Microgreens
• Strawberries
• Potted citrus and fig trees

Best Leafy Greens and Vegetables to Grow in a Winter Greenhouse

Leafy greens are the undisputed champions of winter greenhouse growing. They are fast-growing, nutritious, and require minimal heat to thrive.

• Lettuce
  Loose-leaf varieties such as ‘Winter Density’ and ‘Arctic King’ are specifically bred for cold conditions. Harvest outer leaves continuously for weeks.
• Spinach
  Extremely cold-tolerant and rich in nutrients. Grows slowly in winter but remains fresh and flavourful.
• Kale
  One of the hardiest brassicas available. Flavour actually improves after a cold spell.
• Swiss Chard
  Colourful, productive, and tolerant of low temperatures. A reliable winter staple.
• Pak Choi
  Quick to mature and well-suited to cool growing conditions.

Sow leafy greens in succession every two to three weeks to ensure a continuous harvest rather than one large glut.

Best Herbs to Grow in a Winter Greenhouse

Fresh herbs in winter are a genuine luxury, and a greenhouse makes them entirely achievable. Most herbs slow down in the cold but continue to produce if given adequate light and protection from frost.

• Chives
  Incredibly hardy and productive even in cool conditions. Snip regularly to encourage fresh growth.
• Parsley
  A biennial that handles cold well. Flat-leaf varieties tend to be more robust in winter.
• Coriander
  Prefers cool conditions, making winter actually ideal. Prone to bolting in summer heat.
• Mint
  Can be potted up from the garden and brought into the greenhouse to continue cropping.
• Basil
  The one exception; basil needs warmth (minimum 15°C) and is only suitable for heated greenhouses with grow lights.

Grow herbs in individual pots so you can move them closer to light sources or away from cold draughts as needed.

Root Vegetables You Can Grow in a Winter Greenhouse

Root vegetables are often overlooked for greenhouse growing, but they are well worth the effort. They take up vertical space efficiently and store naturally in the ground until you are ready to harvest.

• Radishes
  The fastest-growing root vegetable available. Ready in as little as four weeks and ideal for filling gaps between slower crops.
• Beetroot
  Hardy and versatile. ‘Boltardy’ is a reliable variety for cooler conditions.
• Carrots
  Slow in winter but sweet and tender. Short-rooted varieties such as ‘Chantenay’ work well in containers.
• Turnips
  Fast-maturing and cold-tolerant. Both roots and tops are edible.

Use deep containers or raised beds inside your greenhouse for root vegetables to allow proper development without compacting the soil.

Flowers and Ornamentals Worth Growing in Winter

A winter greenhouse is not purely about food. Growing flowers and ornamentals through the cold months adds colour, fragrance, and even commercial value to your growing space.

• Pansies and violas: Exceptionally cold-hardy and cheerful throughout winter
• Cyclamen: Thrives in cool greenhouse conditions and produces beautiful blooms
• Sweet peas: Sow in autumn for an early spring display
• Primulas: Compact, colourful, and well-suited to cool growing environments
• Bulbs (tulips, narcissi): Force bulbs in pots for early blooms well ahead of the outdoor season

Temperature Requirements for Common Winter Greenhouse Crops

Understanding minimum temperature thresholds is essential for planning your winter growth successfully. Use this table as a quick reference when deciding which crops suit your greenhouse setup and heating capacity.

Which Plants Need Grow Lights and Which Do Not

Winter days are short, and reduced light is one of the biggest limiting factors for greenhouse growing between November and February. Understanding which crops manage on natural light and which need supplemental lighting will save you both money and disappointment.

• Plants that manage on natural winter light alone: kale, spinach, lettuce, Swiss chard, chives, parsley, coriander, radishes, beetroot, turnips, pansies, cyclamen, and violas.
• Plants that benefit significantly from growing lights: tomatoes, cucumbers, peppers, basil, microgreens, and seedlings started before February.

This is also why growing herbs in individual pots is so useful you can reposition them easily as light conditions shift throughout the season.

LED grow lights are the most energy-efficient option for winter greenhouse use. Position them 30–60 cm above the plant canopy and aim for 14–16 hours of light per day for fruiting crops.

Watering and Soil Tips for Winter Greenhouse Growing

Overwatering is the single most common mistake made by winter greenhouse growers. Cold temperatures slow plant metabolism significantly, which means plants absorb water far more slowly than they would in summer.

• Water less frequently
  Check soil moisture by pressing a finger 2–3 cm into the compost. Only water when it feels dry at that depth.
• Water in the morning
  This allows any excess moisture on leaves to evaporate before temperatures drop at night, reducing the risk of fungal disease.
• Use well-draining compost
  A mix with added perlite or grit prevents waterlogging, which is a leading cause of root rot in winter.
• Avoid wetting foliage
  Direct water at the base of plants only.
• Reduce feeding
  Most plants need little to no fertilizer in winter. Resume feeding in late January or February as light levels begin to improve.
• Keep good ventilation
  Open vents slightly on mild days to prevent the humid, stagnant air that encourages mould and mildew.

Winter success inside a Greenhouse comes down to balancing matching crops to temperature, light, and available space. Hardy greens reward minimal effort, while fruiting plants justify added heat and lighting. Careful watering and ventilation prevent most common problems. When managed thoughtfully, winter growing becomes steady and reliable rather than challenging.

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