Just bought a 400w MH (actually its a hps system with a mh conversion bulb) and i am using one of those environment meters that monitors the temp inside, outside, and the humidity. I know i need to keep my temp between 70-80 degrees (F), but is that the normal temp in the room or is is the temp next to the plant. The reason i ask is because i placed the little sensor for outside temperature on top of the soil in one of my pots and it reads a good 7-12 degrees higher than the temperature in the room.Thanks in advance
you want the temp where your plants are...best place is at the top of the plant. does it really matter what the temp is on the other side of the room? think about it.
I place my sensor directly under the light at plant-top height. This way I know the max temp that the plants are exposed to. To hold the sensor I bought a wood dowel, cut a small block off a 2x4, drilled a hole in the block same size as the dowel, stuck the dowel in the hole so now the block is a base to hold the dowel standing straight up. Then I just put that in between the plants. I cut a segment of a drinking straw and clipped that to the top of the dowel then used a paper clip to hold the sensor on the top of the straw. I can easily move the straw up and down that way to make sure it is at the right height.
That is a good idea toastybiz. I wasn't talking about outside the room i was talking about off to the side of the plants, its a walk in closet. I have the little sensor thing at the bottom of the plant sitting on top of the soil, but i am going to try toastybiz's idea.