Purple stem/leaves doesnt improve with warm weather?

[emcd124]

I have a number of seedlings that I started from seed this year. They are planted in promix and were wintersown outside in milk jugs.

Of the 10 or so varieties I started only two seem to have produced small but healthy green seedlings (a GWR cherry and Golden Champion). The rest (Mex Midget, Super Sweet, SNFLA, Blondkopfchen, Chocolate Cherry and Gold Medal) all are tiny, spindly, with deep purpling on the stem and leaves. They are runts with curling suffering leaves and have stayed more or less that way for three weeks now with little growth.



Internet search suggests cool weather produces purpling of stems and leaves (perhaps because it stunts phosphorus uptake). The recommendations typically seem to be to just wait it out because it will correct itself once weather warms. But these plants have been outside in very warm weather for the past two weeks: at least 70-80 during the days and above 50 at night. Yet they seem to show no signs of improvement, and if anything the purpling is getting more pronounced and the leaves curling more.

Questions:
1. How long a period of warm weather does it typically take to correct the problem? Should I have seen improved growth and greening with 2 weeks of good weather?
2. Other than waiting, is there anything else I should do for these little guys? Repot them?
3. Is there any chance these will still recover in time to be viable plants in my z5 garden or is it time to abandon hope of growing from seed this year and resort to some sad big box starter plants?