Posted: 22/07/2014 at 06:46
I think you are taking two risks. First sowing and growing indoors, whilst often necessary in cold climes, risks the plants becoming leggy ( tall and thin and weak) as they reach for the light which is never as good as outside, even in shade. Second using plastic bags will risk damping off ( technical term for quickly going mouldy, followed by death!).
If you have time why not start a new batch out of doors as recommended above, as belt and braces?
Good luck, we all learn as we go. i still do after yonks