Does the hand method really work?

[madseason]

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.

[killerweed420]

The closer you can keep a light source to the plants the tighter they'll stack thus producing tighter buds.
But while still young the heat can kill them. I wouldn't let them get pass 80 degrees.

[moody420]

I would worry more about temps than location of the light. I usually keep my light no more than 12" away from the tops of plants. I've even put them closer like 6-8" away. As long as you have good airflow and are keeping the temps under 80 degrees....you should be fine. When they are stretching, that is a good thing....it means they are reaching for that glorious light! :jointsmile:

[madseason]

ok thanks guys. just put in a fan, set it on low and pointed it towards the plants. got it down to 74 degrees. had it 86 degrees the first 36 hours. yikesss. :thumbsup:

[Ocotillo]

Lets say you have a sealed hood with ventilation pipes and the 400W bulb is 6" up in that baby above the glass. The hand method leaves me wondering too because I can put my hand very close and not get "burned". :gunfighter2:

Q: Do you measure from the hood glass OR from the bulb? Could be the difference of 12" or 18"... :what:

I'm aiming for BIG Colas some where between Ron Jeremy and John Holmes "The Legend" size. :eek:

[busybee]

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.

hi madseason,yes there is an advantage,at 6" the light is much more intense than it is at 20"+!:thumbsup:

[ledtime]

This doesn't work for me. Any closer than 14" with my 400W and my leaves start to bleach....

[killerweed420]

Have the same problem with my 1000w. Have to keep about 24 inches away.