Yikes, everything was going smothly hardening off my seedlings and cuttings. but then this moring, in my makeshift, transitional green house, 4 plants,that I just put out there last evening, and two tender tropicals (accustomed to the sun and temperatures for a week) were totally wilted this morning, like they were hit by a frost. These were the most tender of all the plants out there, as the others had been hardened off, either partially or fully. Now, last night I left the door open to the greenhouse, and it was vented well at the top. I have done this all week since it has been mild. Got up late this morning and noticed a chill, but no frost. However, when I went to the greenhouse, these plants look unrecoverable. :(

The filtered sun I appropriated for them had not hit them yet and it was just warm in the greenhouse, so heat and sun were not factors, yet something has wilted them!

Could a cold snap, without frost, effect newly placed outside tender indoor plants?

Some 25 brugs I have outside that are hardened off completely, with all their leaves, didn't suffer a bit!

What has happened? Never seen any sudden massive wilt unless the cat peed on them, or a plant got wet feet, which isn't the case, and there is no cat.