My first seeds of the year are in the hardening off stage. Cabbages, kohlrabi, leeks, tomatoes and peppers are in a cold frame. The tomatoes and peppers are coming inside in the evening since temperatures are getting down close to freezing. The hardier veggies are staying out all night.
Low tech (cheap) is my style. I don’t have automatic venting that lets more air in as temperatures rise. In the morning, I check the forecast and decide how big the gaps between the window panes should be. A completely covered block frame could easily cook the little plants on a sunny day. I’ve used this set of blocks and window panes for several years and have used a thermometer to see how warm it gets inside.
These little plants got their start indoors. The indoor set up has a little more control. I have my shop grade fluorescent lights and a fan plugged in to a power strip. The power strip is plugged to a timer set to be on 14 hours a day. When I tried seed starting without a fan, I lost seedlings to damping off. Having good air flow and not over watering are keys to eliminating the damping off microbes.
This set up is making it possible to grow my own heirloom varieties and get healthy seedlings started at very low cost. Its always good to see the babies getting started.