measuring light distance

On my 600 wat hps light do I measure from the tops of my plant to the bulb or to the lowest part of the lights reflector ? Nuff love people

Best is to measure temperature at canopy, then you can see how close you can get the lights, the closer the better, be sure to have fans running.

otherwise i believe its 15-20 inches

FJG

Light distance is entirely judged by heat. I use 2-150 Watt HPS Lights, so I can have my lights very close to the tops. With a 600 Watt HPS, you will need more distance than me, BUT, if you can control your heat above the plants, you can move your light closer, which will be excellent for bud production.

Placing fans at your canopy level (which I do), helps really well with heat distribution. Also making sure you have good roof ventilation above your lights will keep your temps, down. I have a Sativa growing in my closet right now that is almost 5 feet tall, and the bud towers get very close to my lights, with no problems to my plants. In fact, the closer they get, the fatter the buds are.

I use the method of placing my hand over the canopy and feel if it get "Warm" ... I adjust accordingly..

I also have fans blowing between the lights and canopy..

Thanks guys !! And by canopy you meen the tops of all the plants correct ? And if its warm on my hand then I shud move the lights up ? Or measure the temps between light and tops of plants ?? And an extra question if you don't mind answering some of my plants are rather short and bush with 3 main stems is I tie these 3 back to open the plant up a bit will this help the buds in the middle and down the bottom get bigger as they won't be blocked as much by the other bigger buds ?

FWIW I have a temp and humidity unit taped to a small metal rod and stick it in the soil where it is even with the top of the canopy, directly under the bulb.

Eurohigh said:

I use the method of placing my hand over the canopy and feel if it get "Warm" ... I adjust accordingly..

I also have fans blowing between the lights and canopy..

Click to expand...

HPS kicks ASS! And, they are cooler than MH.

ramraid said:

Thanks guys !! And by canopy you meen the tops of all the plants correct ? And if its warm on my hand then I shud move the lights up ? Or measure the temps between light and tops of plants ?? And an extra question if you don't mind answering some of my plants are rather short and bush with 3 main stems is I tie these 3 back to open the plant up a bit will this help the buds in the middle and down the bottom get bigger as they won't be blocked as much by the other bigger buds ?

Click to expand...

Yes Canopy = top of the trees.. And yes to the "And if its warm on my hand then I shud move the lights up" The last i cant answer.. I grow only by the scrog method and i dont got that issue with that technique..