harden off

British

verb

(adverb) to accustom (a cultivated plant) or (of such a plant) to become accustomed to outdoor conditions by repeated exposure

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Remember to harden off, or acclimate, homegrown starts by giving them a few midday hours of sunbathing for about five days before planting them outside.

From Seattle Times • Apr. 28, 2022

If possible, move the potted seedlings into a cold frame to harden off for a few days before planting.

From Seattle Times • May 19, 2016

You can leave the tubers in the ground for a couple of weeks to harden off a bit, and then lift them carefully with a garden fork.

From Washington Post

When large enough prick off the seedlings into boxes of good light soil, and gradually harden off in readiness for planting out in May.

From The Culture of Vegetables and Flowers From Seeds and Roots 16th Edition by Sutton and Sons

Sow the seed early in spring in a slight heat, harden off gradually, and put out at the end of May in a warm, sheltered spot.

From Gardening for the Million by Pink, Alfred

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023