The outside temp ranges from an overnight low of 75 to a late morning high of 90. The 10" x 20" box is running 4 x 23 watt CFLs, on 18/6, with the dark period in the afternoon. Even with the lights quite high, temps can get up 95 in the late morning. I know ventilation and negative pressure is recommended, rather than intake fans. But if a fan was added to draw outside air in, blowing it straight over the seedlings, would this be a better way of keeping them cool? Or would it be better to just have the two 4" fans at the top and increase ventilation openings in the bottom?
I have had the same issue as you with my temp getting 90ish while using the exact same set up. I had to use several fans on both sides to keep Temps manageable. Those 4" fans don't cut it. I had lots of wind across my babies just to stay in the mid to low 80's .
