Sow French and runner beans, squash, cucumbers and pumpkin seeds directly into prepared beds outside - in colder areas may be wait until the end of the month. Be alert to late frosts (for which a covering of horticultural fleece should provide sufficient protection). French beans are best sown in traditional rows at 15-23cm (6-9in) spacing.
Sweetcorn works best sown in blocks, at 45cm (18in) spacing, with two seeds per hole. The strongest seedling can be selected later, and you will have the safety of knowing there is a fall-back in case of one seedling being devoured by slugs (link to advice) or similar.
Runner beans benefit from well-prepared ground with lots of well-rotted manure and organic matter dug in. They need to be planted alongside suitable supports (often a frame or wigwam of bamboo canes tied together with twine) for the shoots to twine around and grow upwards.
Sow cauliflowers and purple sprouting broccoli for harvesting next winter.
Try sowing some unusual vegetables such as kohl rabi (like a large white above-ground turnip), scorzonera and salsify (both of which produce edible roots, which are boiled and peeled like parsnip and are said to taste a bit like oysters).
Brussels sprouts for next winter should now be ready for transplanting after early or mid-spring sowing. The gaps between them can be used for short-term ‘catch-crops’ like radishes or gem lettuces, as they will take time to grow into their recommended spacing requirement.
Material courtesy of www.rhs.org.uk