New Grower Newbie Grower 600w HPS questions

[casualsm0ker1889]

hey guys im asking a question for a friend (I'm hoping to start AF growing in a year or two when i move out of my parents place) and i'm just a member of here because i find your journals fascinating and looking at your end results is... well :drool:



Anywho, he only uses a single 600w HPS light and he isn't certain about the heat on the back of your hand method so i came here hoping someone could give him a better solution to how far away the light should be and when he should start the light on them. (As soon as they pop their heads out of the soil, should it be directly under the light or not etc.)

Any help would be greatly appreciated. :smoke:

 

[casualsm0ker1889]

bump

 

[Gonzo]

These are charts from CaliGrower, hope you will be able to see them.

Otherwise google for: mh hps chart

 

[Gonzo]

You can start with 600W from the first day but the distance is very important.

29 inches is the highest distance, where usable light happens. HPS is not very good for the first month.

 

[casualsm0ker1889]

Thank you very much thats perfect. No chance of doing any damage even from day 1? And if it was started at 29 inch then would it have to be brought down maybe an inch per day for a couple of weeks? (To avoid stretch)

 

[Gonzo]

Maybe 29 is a little bit too close for the very first days. If seedlings are lack of light, they immediatelly start to stretch and they will stretch until they will not be able to stand up any more. So better start a bit higher with beast and lower it immediatelly when/if any undesired stretch, but monitor seedlings immediately after they come out and develop. I read that HPS in early stages of growth is also stretchmaker, by the way. Well, it grows anyway,no fear.

Overall, 600 W is beautifull thing later on in flowering, but not really the best one in first days of seedling.

 

[greenzilla]

I've started from seed under 600w and they've been just fine no problems during veg what so ever. Light was set up at 1 meter above pot and stayed there for around 21 days then lowered to about 30cm but that was too close, upped to 50cm then gradually lowered to back down to what the plants would take roughly 40cm. Hope that helps