What to Sow in April: UK Allotment Planting Guide

crissowden
Mar 31
3 min read

April is the month most UK allotment holders have been waiting for all winter. The soil is warming, the days are lengthening, and the growing season is finally underway in earnest. But April can also catch you out — late frosts are still very much a risk in most parts of Britain, and rushing tender crops outside too early can set you back weeks. This guide tells you exactly what you can sow, what to protect, and what to hold off until May.

April Weather: What to Expect in the UK

April is notoriously unpredictable across the UK. Soil temperatures are typically between 8–12°C in most regions, warm enough for many seeds to germinate but not yet warm enough for tender crops. Frost risk remains real, particularly in northern England, Scotland, and elevated sites, and a cold snap can arrive without much warning even in the south. Always check local forecasts before planting tender crops outside.

What to Sow Directly Outside in April

These crops are hardy enough to be sown directly into the ground in April across most of the UK:

Carrots — sow in drills 1cm deep; thin to 7cm once established. Earliest outdoor sowings benefit from cloche protection in colder areas.
Beetroot — sow in rows 30cm apart, 2–3cm deep. Succession sow every 3 weeks for continuous harvests.
Parsnips — sow now for autumn harvest; germination is slow (up to 3 weeks). Sow thickly and thin later.
Peas — direct sow in April into moist soil. Support with pea sticks or netting from the start.
Spinach — sow in rows 30cm apart; thin to 15cm. Prefers cool conditions so April is ideal.
Salad leaves — sow little and often from now through September. Mix varieties for continuous picking.
Spring onions — quick and easy; sow direct and thin to 1cm apart.
Radishes — sow every 2 weeks for continuous harvest; ready in as little as 4 weeks.
Broad beans — if not already in the ground, early April is the last good window for outdoor sowing.

What to Sow Under Cover or Indoors in April

Tender and half-hardy crops need to be started under cover in April, ready to plant out once frost risk has passed (usually late May in the south, June in the north):

Courgettes and squash — sow individually in 7–9cm pots on a warm windowsill or heated propagator. Plant out late May–June.
Tomatoes — if not already started, April is your last chance; sow in a propagator at 18–21°C.
Cucumbers — sow in individual pots with warmth; they are frost-tender and need 6–8 weeks before planting out.
Peppers and chillies — if not already started, sow now; they need a long growing season.
French and runner beans — start indoors in root trainers or deep modules for planting out in late May.
Leeks — sow in trays under cover; prick out when pencil-thick and plant out May–June.
Brassicas (cabbage, broccoli, kale) — sow in modules under cover for planting out May–June.
Sweetcorn — sow in individual pots under cover in late April for planting out in late May.

What to Plant Out in April

As well as sowing, April is the key month for planting out crops started earlier:

First and second early potatoes — plant now if soil is workable and not waterlogged. Earth up as shoots emerge.
Maincrop potatoes — plant in April for August–October harvest. Space at 37cm, rows 75cm apart.
Onion sets — push sets into prepared soil with tip showing; space 10–15cm apart.
Shallots — plant in the same way as onion sets; slightly earlier in spring is better.
Asparagus crowns — April is the ideal month to plant new asparagus crowns. Do not harvest in the first year.
Onion transplants — plant out module-grown onions once large enough to handle.

April Allotment Jobs Checklist

Hoe between rows weekly to keep weeds down before they establish
Earth up potatoes as shoots emerge — this protects from frost and increases yield
Keep fleece handy — April frosts can arrive without warning