A growing year, under glass.Practical advice for UK gardeners
HomeTHE GREENHOUSE YEAR

March in the greenhouse

Longer days make this a useful month for propagation. A sunny greenhouse can still be followed by a freezing night.

UK seasonal guidance · Reviewed September 2026

Start with your conditions. Dates are a guide. Northern and exposed gardens can be several weeks behind sheltered southern ones. A greenhouse without heat does not guarantee frost protection.
01

Sow

Sow greenhouse tomatoes indoors, and make small sowings of lettuce, radish and hardy herbs. Give peppers and chillies warmth for germination.

02

Grow

Pot on seedlings once roots hold their compost together. Handle them by a leaf and water gently after moving.

03

Harvest

Pick the last winter salads while young spring leaves begin to fill the gaps. Do not strip plants bare.

04

Jobs this month

Clean the space for summer crops, arrange supports and keep fleece ready. Ventilate before heat builds on sunny mornings.

Make your own growing notes

Record what you sowed, your overnight minimum temperature and how the plants responded. Check the compost below the surface before watering: the same calendar date can bring very different conditions from one year to the next. Use the seed packet’s variety-specific guidance alongside this monthly plan.

For tender crops, distinguish the warmth needed for germination from the conditions needed after seedlings emerge. For winter leaves, choose varieties intended for the season and allow for slower growth as daylight falls.

Further reading: RHS greenhouse vegetable growing.

GROWERS’ NOTES

What’s happening in your greenhouse?

Ask a growing question or share your experience. Comments and replies are checked before publication.

Loading approved comments…

FURTHER READING

Keep growing your knowledge.

Explore useful books with reading levels, practical notes and links back to our growing guides.

Browse greenhouse beginners books ↗