Whether you're a first-time grower or a seasoned gardener, knowing what to sow and when is the foundation of a productive garden. The UK's climate means timing is everything — sow too early and seedlings struggle in cold soil; too late and you miss the growing season entirely. This guide takes you through every month of the year so you always know what to do next.
📥 Want to track your sowing schedule as you go? Download your free Seed Sowing Tracker PDF and keep it to hand throughout the season.
What You'll Need Before You Start
Before diving into the calendar, make sure you have the right equipment to give your seeds the best start:
- Seeds — browse our full range of Bulbs, Seeds and Tubers to find the right varieties for each season
- Seed trays — Grow It Standard Seed Tray or the Westland Gro-Sure Visiroot Twin Propagator Set for a complete setup
- Propagator lids — Grow It Half Seed Tray Lid to retain warmth and moisture
- Heat mat — Westland Gro-Sure Heated Propagation Mat for germinating heat-loving seeds indoors
- Cell trays — Westland Gro-Sure Visiroot 9 Cell Tray for pricking out seedlings
- Compost growing discs — Grow It Peat Free Compost Growing Discs — ideal for small spaces and mess-free sowing
- Gloves — Kent & Stowe Water Resistant Gloves for outdoor sowing
Browse our full Bulbs, Seeds and Tubers collection and Tools, DIY and Clothing collection to stock up.
January — Sow Indoors, Plan Outdoors
January is quieter in the garden but the perfect time to start planning and get a head start indoors.
Sow indoors: Onions, leeks, sweet peas (for early flowers), chillies and peppers (they need a long growing season).
Outdoors: Broad beans can go in under cloches in milder regions. Most outdoor sowing is too early this month.
Top tip: Use a heated propagation mat to maintain consistent soil temperature for chillies and peppers, which need warmth to germinate reliably.
February — Early Starters
Days are lengthening and light levels improve. More seeds can go under cover now.
Sow indoors: Tomatoes, aubergines, celery, celeriac, early lettuces, antirrhinums, and begonias.
Outdoors: Broad beans and hardy peas in sheltered spots.
Top tip: A windowsill propagator is ideal this month — maximises light while keeping seedlings warm.
March — The Season Begins
March is one of the busiest sowing months. Soil starts to warm and the range of sowable seeds expands significantly.
Sow indoors: Courgettes, cucumbers, squash, French beans, basil, half-hardy annuals (cosmos, marigolds, petunias).
Sow outdoors (direct): Carrots, parsnips, beetroot, spinach, radishes, spring onions, hardy annuals (cornflower, calendula, nigella).
Top tip: Protect early outdoor sowings with a Grow It Polythene Grow Tunnel to extend the season and guard against late frosts.
April — Peak Sowing Season
April is arguably the most important sowing month in the UK calendar. Soil temperatures rise and the risk of hard frost reduces in most regions.
Sow indoors: Runner beans, sweetcorn, tender bedding plants.
Sow outdoors (direct): Peas, lettuce, kale, chard, turnips, leeks, herbs (parsley, dill, coriander), hardy annuals.
Top tip: Watch for slugs as seedlings emerge — Growing Success Slug Killer or Copper Tape around trays and beds will protect vulnerable young plants. Browse our Weed and Pest Control collection for the full range.
May — Last Frost, Full Speed Ahead
After the last frost date (typically mid-May in most of the UK), the full range of tender crops can go outdoors.
Sow indoors: Final sowings of courgettes, squash, and cucumbers if not already done.
Sow outdoors (direct): French and runner beans, sweetcorn, outdoor tomatoes (in warm, sheltered spots), salad leaves, herbs, sunflowers.
Top tip: Protect young plants from birds and insects with Grow It Protective Crop Netting — essential once plants are in the ground.
June — Succession Sowing
The main sowing rush is over, but June is ideal for succession sowing to keep harvests coming.
Sow outdoors: Salad leaves, radishes, beetroot, French beans, courgettes (for late summer crops), herbs.
Flowers: Biennial flowers like wallflowers and foxgloves for next year's display.
Top tip: Keep seedlings consistently moist using Grow It Water Retaining Matting under pots and trays during warmer spells.
July — Quick Growers Only
Sowing slows in July as the season shortens, but fast-maturing crops are still worth starting.
Sow outdoors: Salad leaves, spring onions, radishes, turnips, kale (for autumn harvest), French beans (early July).
Top tip: Boost growth of established plants with Westland Seaweed Organic Liquid Plant Stimulant — particularly useful mid-season when plants need a lift.
August — Autumn and Winter Crops
August is about planning ahead for autumn and winter harvests.
Sow outdoors: Winter salads (lamb's lettuce, mizuna, rocket), spring cabbages, overwintering onions, land cress.
Indoors: Pot up herbs like parsley and chives to bring inside before the cold arrives.
Top tip: Protect late brassica sowings from cabbage white butterflies with crop netting.
September — Final Outdoor Sowings
The last chance for most outdoor sowing before temperatures drop too far.
Sow outdoors: Winter salads, garlic (from late September), overwintering broad beans, green manures.
Indoors: Hardy annuals like sweet peas can be sown now for stronger plants next spring.
Top tip: Sweet peas sown in autumn and overwintered in a cold frame or cool greenhouse will outperform spring-sown plants. Use a seed tray with lid to protect them.
October — Garlic and Green Manures
Sow/plant outdoors: Garlic cloves, overwintering onion sets, green manures (field beans, winter tares) to improve soil over winter.
Indoors: Nothing to sow, but a good time to clean and store seed trays and equipment ready for next year.
Top tip: Browse our Bulbs, Seeds and Tubers collection for garlic and overwintering bulbs.
November & December — Rest and Plan
The garden rests, but the gardener plans. Use these months to:
- Order seed catalogues and plan next year's layout
- Check and clean equipment — seed trays, propagators, and cell trays
- Sow amaryllis and hyacinths indoors for Christmas colour
Frequently Asked Questions
What is the easiest thing to grow from seed?
Radishes, salad leaves, and sunflowers are among the easiest — fast to germinate, forgiving of mistakes, and rewarding for beginners.
Can I sow seeds in winter?
Very few crops can be sown outdoors in winter, but indoors you can start chillies, peppers, and onions from January with the help of a heated propagation mat.
Do I need a greenhouse to grow from seed?
No — a sunny windowsill and a windowsill propagator is enough for most seeds. A greenhouse helps but isn't essential.
How do I protect seedlings from slugs?
Copper tape around pots and trays is highly effective, or use slug killer pellets around outdoor beds.
Get Your Free Seed Sowing Tracker
We've put together a handy PDF planner to help you stay on top of what to sow and when. Print it out, stick it in the greenhouse, and never miss a sowing window again.
👉 Download the free Seed Sowing Tracker PDF
Shop Seed Sowing Essentials at Grasmere Garden Centre
Need advice? Visit us in store or read our guide to choosing the right compost to give your seeds the best possible start.