Planting out hardened-off seedlings

Hardening off thickens leaves and builds frost and wind tolerance, so plants do not collapse from transplant shock. Planting into moist soil in cool conditions lets roots take hold before the plant has to cope with heat.

When

After hardening off over seven to fourteen days, and for tender crops only once the last frost has passed (late May to early June in most of the UK). Choose a still, overcast day or the evening.

How

1. Harden off first by standing plants outside in the day and bringing them in at night, extending the outdoor time over one to two weeks. 2. Water the seedlings and the zone well beforehand. 3. Make a hole with a trowel, set the seedling at the depth it grew (brassicas and tomatoes can go a little deeper), and firm gently. 4. Space to the final spacing on the packet. 5. Water in and shade or cloche for a few days if the weather turns bright or windy.

Notes

A sudden move from a warm windowsill straight into the garden is the commonest cause of failure. Keep an eye on late frosts and fleece if one is forecast.