Cosmos Bipinnatus Brights Lights seedlings - leaf curl

I have two trays of these which I've grown from seed, all have one set of main leaves.

Yesterday they got a good soaking in the rain (I'm hardening them off) and on bringing them inside late yesterday one was placed in a bright room, the other back in its usual west facing window. I didn't place them back outside today partly because of the lousy weather here (they were wet enough!) and I then managed to forget when it eventually stopped drizzling.

I've only just noticed that the seedlings in the tray placed back in the window has all of the main leaves curling quite a lot, while the other tray (not in a window) is as it usually is with the usual slight bend in the main leaves.

We have barely had any sun today so I can't blame it on that, but what could be causing the main leaves to curl on that one tray of seedlings?

All are from the same seed packet, use the same compost, etc.

Edit: just as an experiment I've now swapped the trays around - will the leaves on the relatively straight ones curl a lot now? Will the ones with a lot of curl straighten out? Stay tuned .........

Edit2: I do have other Cosmos seedlings (Dwarf Mix and Fizzy Rose) but even though some of them were in the same window as the Bright Lights seedlings none of the them have increased main leaf curl.

Some photos:

Those with curled leaves:

http://s59.photobucket.com/user/Dalek99999/media/Bad.jpg.html


Those without curled leaves:

http://i59.photobucket.com/albums/g319/Dalek99999/Good.jpg

 

An update - after being outside overnight they have recovered, the leaves have uncurled and they look fine.

I would still love to know what happened - the only difference between the affected tray and the unaffected one is that the affected one was put into a west facing window for about 24 hours (although due to the weather it barely got any sun that day).

Most puzzling.

 

I was going to post that they should recover and go back to normal , but seems like all is OK now Like us plants especially seedlings can have an "off day" , due to a myriad of reasons - watering , temp , light , draughts etc etc . And most of us , like you , tend to panic and think the blooming things are going belly up

 

Yup, I was rather worried. (after some cabbage seedlings went a similar way (and didn't recover)) I wanted to be sure that I could prevent any imminent failure with the Cosmos. Apparently they didn't need my help though.

 

Just about to sow some of those so will keep an eye out. Yours look so healthy...

 

Barring the temporary hiccup mentioned in this thread I've found them to be extremely easy to grow from seed (planted indoors) - most of mine germinated in only two days.

Good luck with yours.