You can make your own potassium-rich fertiliser comfrey leaves or banana skins Sow some back-up brassicas

by soaking in water before applying.

These unexpectedly warm bouts of weather cause kale and cabbages to bolt, and an overblown brassica is not much good, coming too early and being too straggly to satisfy. If the heat causes your crop to peak too soon, have replacements at the ready and get them in as soon as you’ve cleared away the bolters.

This applies particularly when your crops are under glass or plastic, in a tunnelhouse or conservatory. There’s little you can do about the extra warmth except ventilate and that’s often difficult where there’s no movement from the wind. It’s advisable, when conditions get too hot, to coat the glass or plastic in some sort of water-based screen, such as paint or even a coat of clay and water, which will dry and shield the plants from the sun.

Cabbage white butterflies are searching for brassicas to lay their eggs. If you don’t want cabbages chewed or caterpillars lurking in your broccoli then cover with horticultural mesh. Inspect plants daily and flick off the eggs and squash the caterpillars. A paint brush is handy to winkle eggs and caterpillars out of kale leaves.