April is a ‘let’s go for it!’ month on the allotment but proceed with caution. Hopefully we will all be feeling the benefit of the lengthening days and warm sunshine but beware, there is always a price to pay with the threat of hard, night frosts never far away. Hold back and wait a day or two rather than take a risk. It isn’t the loss of seedlings or young plants that causes the problems but the loss of your precious time that you will never get back that does the damage. The allotment will always catch up eventually and reward your patience with a bumper harvest.
Sowing and planting
Continue with planting out the seed potatoes; aim to complete the job by the end of April. Be prepared to cover the emerging shoots of the earlies with soil if a frost is forecast.
Complete the planting of onion sets and carry on making successional sowings of beetroot, carrots, parsnips, lettuce, spinach, spring onions, kohl rabi, radish, turnips, early peas, Swiss chard.
Sow maincrop peas and make the last sowing of summer broad beans. You could try an early sowing of dwarf and climbing French beans towards the end of the month. Use the darker seeded varieties they are hardier and more suited to the early sowings. Protect them from frosts.
On a prepared seed bed sow the seed leeks and summer cabbage. Plant out celeriac grown on earlier and keep the plants well watered all through the summer.
Sow under glass, in pots and trays filled with fresh seed compost, the seeds of runner beans, sweet corn, courgettes, pumpkins, squashes, outdoor/ridge cucumber.
It is now safe to transplant the cold greenhouse tomatoes in to their final positions keep some frost protection handy.
Plant out globe artichokes, either by slicing slips off the sides of main plants or plant out bought in roots. Seed raised plants sown earlier are best planted out towards the end of the month. Water well and feed regularly to build up the crowns removing any buds that may form as soon as possible.
Plant out Jerusalem artichokes but don’t allow them to overrun the allotment, if left unlifted at the end of the summer they will quickly develop into an impenetrable jungle.
Plant up a new asparagus bed but it will take two more years to establish before producing succulent shoots.
Early sowings of Brussels sprouts will need thinning out this month and the soil for next month’s transplanting of sweet corn, courgettes, marrows, pumpkins and outdoor/ridge cucumbers will need preparing.
Put up the runner bean poles and start to support the growing peas with brushwood or netting.
Prepare seed beds for outdoor sowing of main crop vegetables next month.
Pest and diseases
Check over top and soft fruit for the first broods of aphids and take appropriate action; spray the plant with soapy water (diluted washing up liquid) or squash the flies with your thumb and finger. You can buy insecticides if you prefer, including a fatty acid soap to spray on the plants
Protect any early strawberries with netting to keep birds and squirrels out.