harden off

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harden something off

to accustom a young plant to normal weather so it can be moved from a protected environment to the out-of-doors. We put the plants by the open window to harden them off. We hardened off the plants.
See also: harden, off
References in periodicals archive ?
I try to harden off for a week to 10 days, depending on how "soft" the plants were initially and the weather conditions.
Transplant seedlings once the first leaves have formed and harden off before planting out at the end of spring, placing the seedlings around 30cm (12in) apart in rows 45cm (18in) apart.
Start standing bedding plants outside on warm, fine days to help them harden off.
n Harden off aubergines, marrow, peppers, pumpkins and tomatoes grown from seed before planting outside.
Harden off autumns own cauliflowers as conditions allow to be ready for planting out next month.
HARDEN off young plants, such as leeks, calabrese, cauliflower, pansies and penstemons, which have been in frames.
When the first two leaves are welldeveloped, gradually harden off before planting out - but don't do it too soon as they are frost-tender.
Harden off hanging baskets and window boxes, ready to put into position outdoors when all danger of frost is over.
n Continue to harden off hanging baskets and other annuals in containers ready to put outdoors when all danger of frost is past
Harden off autumn-sown cauliflowers being over-wintered in frames so they will be ready for planting out in March.