Vegetables in April

At last it is time to sow most crops.

April weather is highly changeable in spite of good light levels, and the soil is still cool. All seeds germinate better, stronger and faster when the soil is warm. Try and spot a warm spell coming up on the BBC forecast—it’s so accurate!

Most seed come up better if not sown too deep, lettuce for instance only need a smattering of soil cover, ¼” at most. They appear above ground level in 3-4 days if warm, their first little roots go down quickly too, and so even if the surface looks dry, the soil below should be moist.

This brings us to soil tilth and compost richness in the surface layers of your soil. Germination is definitely quicker if you haven’t dug your compost down out of reach. If you have a layer of really fine rotted compost, like the recycled green waste we use, you can sow into this, rather like sowing in a seed tray, so long as you have worked a fine tilth in the soil layer beneath. The idea of a fine and firm tilth is that seeds won’t drop down through cracks, rather the crumby soil will surround the seed and keep it moist and fed.

We find it easier to sow indoors in modules. Just as with outdoor sowings, make sure the compost is well wet when you sow the seeds and cover lightly. They should not need watering every day, as the first roots go down into the moist compost beneath. Too much water prevents seeds and roots getting air. Composts now on the market without peat are more likely to waterlog.

Tiny seeds like celery and celeriac should be sprinkled on the compost surface. As they take 2-3 weeks to germinate, we put cling film over the top and leave in the airing cupboard for 10 days to get the seed thinking of coming up, and then move to the warm greenhouse.

Mid-month we sow courgettes, squash, basil and sweetcorn in the warmth of the greenhouse, and from the beginning of May our French and runner beans. None of these like being overwatered, especially basil.

And how do you know if the soil is warm enough? Take your trousers down and park yourself on the soil. This is revealing for you, the soil and those around you.