Hi, welcome to GoY, it will depend on where you've been growing them, if you've had them indoors, or in a greenhouse, you will have to harden them off before you plant them out, but I wouldn't do it until the end of the month at the earliest, if you've grown them outside, they wont need hardening off, so you can plant them at any time, as long as the ground isn't frozen or waterlogged, Derek.