Very young, just germinated seedlings can easily be scorched and killed by exposure to sun - thus the warning - because if they pop up when you are at work or such they can be dead by the time you get home.

Fluorescent light set-ups don't pose that problem - one reason why so many of us use them. ;) But once the plants develop their first true leaves they can tolerate window sun with few problems (unless you have a mammoth window).

Exposing the peat pellets to sun won't hurt the seeds since they haven't germinated yet but exposing them to the air is sufficient to dry them out. You can also just squeeze some of the excess water out of them.

Try keeping your cover on a night but propping it open 1/2 way during the day - out of the sun. That will help control the moisture levels.

Good luck with your plants.

Dave

Dave, thank you. You've really helped me out! :)

I had a glut of wallflowers germinate when light was excluded. I had them in my garage with the door closed when I lived in the UK. I have now returned home and tried to germinate wallflowers in my coldframe with zero per cent success. However I have had a very favorable result in germinating tomatoes, onions and peppers in my heated propagators on the ledge in my drawing room.

While the wallflowers I sowed did not succeed I did find a self sown wallflower in the gravel of my path which I transplanted to the bed. Just shows nature really does know best.