Definition of harden something off in English:
Inure a plant to cold by gradually increasing its exposure to it.
- Add moisture retaining granules and slow release fertiliser to the compost and gradually harden the plants off before putting them outside completely at the end of the month.
- Not everyone has the luxury of a greenhouse, but plants can be hardened off by taking them outdoors during the day and bringing them in again in the late evening.
- Gradually harden them off over three to five days by putting them in a protected shady spot, first for half a day, then a full day, and then gradually into full sun.