The red color is a indication the plant is being grown to cold.. crank up the heat.

Agree it is just cool growing temps that cause it but it does no harm to them. The plants green up quickly when planted outside and the weather warms.

If you want to warm just the growing area a bit without heating the whole house just enclose the plant area a bit with a plastic drop cloth and let the lights provide a bit of heat to them. That means leaving the lights on a night and off some during the day. Get a timer. ;)

Dave

Thank you both! =)