Right now my sprouts are about 20" from my 400w hps. I put my hand over them for a minute or so and my hand felt less than warm, but then I laid my thermometer on the plastic cups, waited a couple of minutes and read 80 degrees. The sprouts are stretching, move it up? or keep it the way it is?

Also, are there any advantages of keeping a plant 6 inches away from the light, rather than 20+"? lets say at both heights you can get the tempertaure right around 78 degrees.
madseason Reviewed by madseason on . Does the hand method really work? Right now my sprouts are about 20" from my 400w hps. I put my hand over them for a minute or so and my hand felt less than warm, but then I laid my thermometer on the plastic cups, waited a couple of minutes and read 80 degrees. The sprouts are stretching, move it up? or keep it the way it is? Also, are there any advantages of keeping a plant 6 inches away from the light, rather than 20+"? lets say at both heights you can get the tempertaure right around 78 degrees. Rating: 5