Chillies, peppers, and cucumbers

To be safe, continue to sow indoors. Outdoors in April, seeds may not germinate, even under cover.

Even once they’ve germinated keep chillies indoors. They still need a minimum temperature of 18ºC (64ºF) during the day and 16ºC (61ºF) at night.

Aubergines and tomatoes

April is probably your last chance to sow seeds indoors for transplanting out. Any later and the plants will have too short a growing season for fruits to ripen outdoors.

Broccoli, cabbages, and other brassicas

Brussels sprouts, calabrese, sprouting broccoli, summer and autumn cauliflowers, and cabbages of all kinds can now all be sown outdoors. Either sow them in pots or modules, or in a prepared seedbed from which you can transplant them in a couple of months’ time.

Carrots, beetroots, and other root vegetables

Most root crops can now be sown outdoors. Indeed, April may be your last chance to sow parsnips. Beetroot may need covering with cloches if the soil is cold and wet.

Celery, chicory, endive, and Florence fennel

Sow indoors to ensure that seeds germinate successfully. Harden off next month, and plant out in June.

Courgettes, pumpkins, and other squashes

Sow seeds indoors ready for planting out next month – or when you’re sure there will be no further frosts.

Leaf vegetables

Spinach, Swiss chard, and Oriental leaves such as mizuna, mibuna, and komatsuna can all be sown outdoors now, although prepare to cover them if necessary. Kale is best sown in pots or modules indoors.

Oriental mustards sown under cover in seed trays should now be emerging. Pick them young for use in salads.

Leeks and onions

Sow leeks outdoors now, either direct in the ground on an area of your plot reserved as a seedbed or clustered in modules or multiblocks for transplanting later. You can sow onion seeds, too, if you’re not growing them from sets.

Lettuces and other salad crops

Sow lettuce, rocket, land cress, summer purslane, corn salad, and other salad leaves outdoors this month, under cover if the weather is still cold.

Melons

Sow seeds one per pot, cover them with a plastic bag, and put them somewhere warm – an airing cupboard or propagator. When seedlings appear, move them into the light on an indoor windowsill or in a heated greenhouse.

Peas and broad beans

Continue to sow both pea and broad bean seeds outdoors, protecting them with cloches if the weather is still cold.

Sweetcorn

Sweetcorn has a long growing season so it’s worth starting early by sowing seeds in pots indoors.

Herbs

Follow up on last month with further sowings. Almost all herbs can be sown or planted outdoors now.

French and runner beans

To get ahead, sow a few seeds in pots and keep them on an indoor windowsill or in a heated greenhouse.