What are some signs that its too hot for a plant other than temperature. I've got a lowryder 2 seedling going, which is supposed to be very versatile and grown in any climate. The temp has gotten up to 88F at some points in my cab even with fans on, but the seedling seems to be doing great so far regardless of the heat, so I'm assuming the temp is okay. What can I watch for so I can try to lower the temp before it hurts my plant?
Look up heat stress. Even though your plant may do ok at 88F, th potency will suffer. Ideally 75F is the perfect temp.
Temp has maxed at 88F with lights on, but usually around 80-83F, and with lights off around 69-74F. I've tried to keep it at 75F with the lights on, which I can with the fans on full speed and moving it further from the light, but I thought it was stretching back towards the light when I moved it. Plus, I can't keep the fans on full all the time because its too loud. I didn't know potency could be affected though, is it better to keep the lights further away to lower the temp?
That's not so bad. With good air movement in the room, and air blowing across the tops, you shouldn't have to move them too far from the light. It sounds like you have a pretty stable set-up, a few peaks in temperature won't kill them.
My second of the two I germed broke the soil today so I had to angle the lamp to cover both. This forced me to slide the first seedlings pot over a little to get light to both and temps have stabilized now at 80-83F without jumping to 88F anymore. Plus, the light seems to be just as effective. My cab is 26" x 26" x 14" with a 70w HPS in the upper left corner shining down at about a 45 degree angle to both. Obviously, the pot closest to the right side of the cab (newer seedling) isn't getting as much light/heat as the older seedling, so I'm thinking of mounting a 42w warm cfl in the upper right corner, depending on temperature. But I'll play it by ear.