🌱🏡 What to Plant in a Greenhouse Each Month (UK)
🥕 Introduction: Using a Greenhouse All Year in the UK
A greenhouse allows UK gardeners to extend the growing season at both ends, protect crops from unpredictable weather, and grow vegetables that would struggle outdoors. From early seed sowing in winter to late harvests in autumn, a greenhouse can be productive every month of the year.
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This month-by-month guide explains what to plant in a greenhouse each month in the UK, helping you plan sowing, planting, and succession growing for consistent harvests.
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• Seed Trays & Module Pots
Perfect for organised greenhouse sowing.
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• Heated Propagator
Improves germination during colder months.
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• Ventilation & Shade Accessories
Helps control temperature and airflow year-round.
Click here to see them
🌱 January – Careful Early Starts
Greenhouse planting begins slowly.
✔ chillies
✔ peppers
✔ onions (from seed)
✔ leeks
Supplementary heat and light are beneficial.
🌱 February – Increasing Activity
More crops can be started.
✔ tomatoes
✔ aubergines
✔ lettuce
✔ herbs
Ventilation on mild days prevents mould.
🌱 March – Peak Greenhouse Sowing
March is one of the busiest months.
✔ tomatoes
✔ cucumbers
✔ lettuce
✔ brassicas (cabbage, cauliflower, broccoli)
✔ basil
Hardy plants may be moved to cold frames later.
🌱 April – Transition Month
Greenhouses are full and active.
✔ courgettes
✔ squash
✔ pumpkins
✔ sweetcorn
✔ cucumbers
Begin hardening off late in the month.
🌱 May – Planting Out and Final Sowing
Some crops remain under cover.
✔ cucumbers
✔ tomatoes (greenhouse varieties)
✔ basil
✔ peppers
Most seedlings move outdoors once frost risk passes.
🌱 June – Summer Growing Phase
Focus shifts from sowing to growing.
✔ basil
✔ lettuce
✔ spring onions
✔ coriander
Shading and watering become essential.
🌱 July – Heat Management and Succession
Greenhouse sowing continues carefully.
✔ lettuce
✔ spinach (summer varieties)
✔ herbs
Ventilation prevents overheating.
🌱 August – Preparing for Autumn
Greenhouse use increases again.
✔ winter lettuce
✔ spinach
✔ spring onions
✔ pak choi
Shade and moisture control remain important.
🌱 September – Overwintering Starts
Autumn crops are established.
✔ winter lettuce
✔ spinach
✔ rocket
✔ chard
Growth slows but plants establish well.
🌱 October – Protected Growing Only
Greenhouse protection is key.
✔ lettuce
✔ spinach
✔ rocket
Remove summer crops and improve soil.
🌱 November – Minimal Sowing
Only hardy crops continue.
✔ lettuce (winter varieties)
✔ rocket
✔ herbs (windowsill or greenhouse bench)
Water sparingly.
🌱 December – Planning and Light Use
December planting is limited.
✔ herbs (windowsill or heated greenhouse)
Focus on cleaning, maintenance, and planning.
❄️🌤️ Greenhouse Growing Tips
✔ ventilate regularly
✔ avoid overwatering
✔ clean glass for maximum light
✔ use fleece inside during frost
✔ rotate crops where possible
Good management keeps greenhouses productive year-round.
🌟 FAQs
Can I use a greenhouse all year in the UK?
Yes. With planning, greenhouses are productive in every month.
Do I need heating in winter?
Only for tender crops; hardy plants need protection, not heat.
What is the busiest greenhouse month?
March and April are usually the most active.
Can beginners use a greenhouse successfully?
Yes. It improves control and success rates.
Should I grow crops in the ground or containers?
Both work well, depending on space and drainage.