Poor you Theresa. They are probably a bit light starved, so they head up too fast, become weak, flop over and usually succumb to fungal disease. Like you, I often try to start things off early, as in Scotland our growing season is short. However, I have limited success using my conservatory to germinate and greenhouse to grow on. It's tricky. They need lots of light and a constant temp to germinate. If you can get them to germinate successfully it gets easier, but if you're using a windowsill it's tricky....too much warmth and not enough light....good luck!

This is called 'damping off' Theresa and can be caused by several things either singly or several together. A major cause is, as Karen says, not enough light. If you are really keen and don't mind spending a few quid for future use then go to my few blogs. There is one on light boxes designed for the 'not really very technical' gardener. Another cause is too warm for the amount of light available. Centrally heated houses tell the plant it is summer, short daylight hours tell it it is still winter. So it gets what in a human would be called 'confused' and tries to grow too fast for the light conditions. Yet another possible cause is wrong watering. Young seedlings don't need to be sopping wet. They should be watered either from the bottom by standing in water for a while when dry to the touch, or with a fine water spray from the top, clean rain water if you can get it.

Too late to do anything really for this batch. Occasionally you can save the odd plant by transplanting it deeper but that is not usually very successful. We have all experienced this so just put it down to useful experience.

Damping off is due to fungal infection of the seed before or shortly after germination.. It used to be treated or, better prevented, with Cheshunt compound, which was taken off the market two or three years ago. If I had known in advance I would have stocked up! I think it was largely copper sulphate. Using sterilised compost and very clean seed trays should help but cold and damp together are a NO NO.

Bordeaux mixture is similar to Cheshunt compound Steragram. They tried to take that off the market too until they discovered that many infections of fruit trees were really only treatable with that. So they went in the opposite direction and declared that Bordeaux mixture is actually organic. Lol. All copper sulphate fungal treatments are poisonous if not used correctly. Easier with trees and perennials, not so good on brassicas. The trouble with using it on vegetables is that it has to be used on the seed before planting otherwise your fungus gets a hold before you can apply it. With good growing practice you shouldn't need it unless you have, say, peach trees. Peach leaf curl is impossible to get rid of without Bordeaux.