Beginner Gardening: Why are my cucumber seedlings so lanky?, 1 by imacajun

imacajun wrote:
I planted cucumber seeds {burpless and straight 8's} 2 weeks ago in the 3" peat pots that you can purchase at WalMart ect. and they were getting so lanky and toppling over so this weekend I transplanted them in tall 6 to 8"plastic McDonald cups with hole in bottom for drainage and they are starting to droop again. I keep them well watered and they are still inside my home with 5 hours of light daily. We're having a late frost Tues. night and my garden is not ready to transplant these seedlings. Should I just scrap all of these seedlings and start over in a week or 2 when my garden is ready or will they be ok? They are green and heathy looking and I thinned them down to one strong plant per cup. When I transplanted to the larger cups should I have gone up to the leaf with the new soil? I just transplanted the way they were in the smaller pots. Should I add more dirt ? See photos.
Any suggestions are sincerly appreciated. Thanks for your time and have a nice week.
I also placed this question in beginner vegetable forum.