It means getting them used to cooler temps outdoors than they've had in the greenhouse or polytunnel where they were produced. Leave them outside by day and bring them in at night to a greenhosue, garage, carport or a sheltered corner that is free form frost. Do this for a week or two till they get accustomed = hardened off.
Vendée - 20kms from Atlantic coast.
"The price good men (and women) pay for indifference to public affairs is to be ruled by evil men (and women)."
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It means getting them used to cooler temps outdoors than they've had in the greenhouse or polytunnel where they were produced. Leave them outside by day and bring them in at night to a greenhosue, garage, carport or a sheltered corner that is free form frost. Do this for a week or two till they get accustomed = hardened off.
You often get ??? instead of
when you're working on a tablet Tanya - no idea why - just happens 
Doing colon, hyphen, close bracket usually results in a smiley on my iPad