Last year Spink built a germination chamber complete with grow lights. Unfortunately, the lights (LEDs) produce too much heat and the chamber has no way to cool down, so he made some modifications and now we just use it to germinate seeds and then move them to heat mats to grow a bit before hardening off and transplanting outside. The germination chamber can hold up to 12 – 1020 trays on 2 shelves (with option to add another shelf in the future). There is a heater inside (white plate) plugged into a temperature controller, a small fan to keep air flowing inside, and a humidifier outside with cold, moist air pumped in to the side via a drilled hole. The entire chamber is insulated.
When we realized the lights make it too hot, Spink built a chamber on top of the germination chamber for the starts to go once they pop up. This is where they go to be under lights. Lights can be moved up and down depending on the height of the plants. In the picture below we moved the lights down closer to the seedlings. This is where they stay for about 3 to 4 more weeks before potting up again or transplanting outside, depending on the plant.