What to Do on Your Allotment in March

March is the turning point. The soil begins to warm, the days lengthen noticeably, and the list of jobs suddenly becomes very long indeed. Prioritise ruthlessly — there is more to do than any one person can manage perfectly, and that is fine.

What to sow in March

Indoors: - Courgettes and pumpkins — start in 9cm pots in a propagator. They grow fast and will be ready to plant out after the last frost in May. - Tomatoes — if not started in February, sow now. Later sowings catch up quickly. - Celery and celeriac — need a long growing season. Sow thinly on the surface of compost (they need light to germinate). - Brassicas — cabbage, cauliflower, Brussels sprouts, and kale for summer/autumn harvest. Sow in modules.

Outdoors (from mid-March, once soil is workable and not frozen): - Peas — sow 5cm deep in double rows, 8cm apart. - Broad beans — make a second sowing if your first is looking sparse. - Carrots — a first sowing under fleece in a sheltered bed. - Parsnips — need a long season; sow now in a well-prepared, stone-free bed. - Lettuce and spinach — both cope with light frosts and will establish quickly. - Radishes — ready in 4 weeks; sow between slower crops. - Beetroot — from late March in warmer areas. - Onion sets — push into prepared beds leaving just the tip showing.

What to harvest in March

• Purple sprouting broccoli — still producing side shoots; keep cutting to encourage more.
• Spring onions — overwintered ones will be ready now.
• Leeks — last chance before they start to bolt.
• Kale and chard — continue cutting young leaves.

Key jobs for March

Plant first early potatoes. When chitted shoots are 2–3cm long, plant in trenches 10–12cm deep, 30cm apart. Cover and earth up as shoots emerge to protect from frost. The variety 'Rocket' is the fastest — you can be eating new potatoes by late June.

Weed early and often. Annual weeds germinate in vast numbers in March. A sharp hoe across the surface every 7–10 days kills them before they root. Fifteen minutes with a hoe in March saves hours of hand-weeding in May.

Set up supports. Get pea netting, bean poles, and canes in place now, before you need them in a rush.

Pests to watch

• Slugs and snails are highly active in wet March weather. Pellets (ferric phosphate, safe for wildlife), copper tape, and regular early-morning patrol all help.
• Pigeons will attack brassica seedlings and pea shoots immediately. Net the moment you sow.
• Carrot fly — avoid sowing near established beds where the pest overwinters.

Quick win: succession sow

Instead of sowing an entire packet of lettuce at once, sow a short row every two weeks from March through July. You will have a continuous harvest rather than a glut followed by nothing.