I know w/hardening off, shortly before they're transplanted, you gradually acclimate the seedlings to outdoor conditions; they're placed in a sheltered area, and gradually the length of time they're outside is prolonged.

My question is, do my seedlings need to be hardened off? They were under a grow light on a heat mat until they germinated; as soon as that happened, they were put outdoors in a sunny area, and have been outside since they sprouted. They've been exposed to outdoor conditions (hot weather, windy weather etc.); the only protection they've had is being brought indoors and/or put in a greenhouse at night when temps drop below 50.

The seedlings are mostly veggies (melons, cauliflower, broccoli, winter squash) and some flowers (currently marigolds and a few zinnias....will also be adding sunflowers, cosmos, nasturiums, and 4'o clocks).

I don't really have time to harden them off, I got a late start w/starting the seedlings to begin with. The cool weather stuff transplants will be probably for fall plantings.