I would harden them off for a week or so before planting them out permanently. Bring the flats inside if temps are expected to go into the 40's at night.

I live on Long Island and usually plant out on Mother's Day weekend, weather permitting.

Do you mean leave them outside for a week or so before planting? I will wait a bit then before planting. If I wait too long to buy them though they are always all gone when I'm ready. Thanks!

Yes. You can buy them now and "harden them off" by gradually increasing their exposure to wind and sun. This process can be done over 1-2 weeks.

If the weather is expected to drop into the 40's, bring the plants inside.

Good luck.

Rokal

They are already on a glassed in sunny terrace. Not much wind where they are going though. Last time I just planted them in the ground right from our terrace and they were fine. I'm not understanding the difference between leaving them outside in their flat, and having them outside planted in the ground.

blondelle,

The plants should stay in the flats while they are hardening off. Once they are fully hardened off, then you plant them in the ground.

Failure to properly harden off your plants will result in stress / transplant shock at best, death at worst.

Please do a Google search on 'hardening off plants' to learn more.

Regards,
Rokal