600hps open hood distances?

I ran my 600hps with glass on and fan running last grow. Heat isn’t too much of an issue right now so I took glass out for veg. I’ll be hitting flower soon and trying to figure out the normal distance between light and canopy? I read 14-24, but seen someone say 36-42? It’s a vivosun 600 hood. If I need to add the glass back I will but was trying not too .

Mrkline, I always err on the side of caution and put the lights further away than likely necessary. I would suggest at least 2ft distance. Maybe 30 inches away is better. Choose a distance, and observe the canopy health of your plant. If leaves begin to fade yellow up top, then the lights are too close and should be moved away.



IME fan leave health tells me when I have the light distance at a good spot. Soft, supple leaves that feel like velvet with a medium shade of green is the sweet spot. If the lights are too close, and plants are being fed heavily, fan leaves turn dark green, feel leathery and course to the touch to the point of being unpleasant.

Also, go buy yourself an infrared thermometer at lowes/homedepot,etc. You can take leaf temp measurements of your plants to help gauge the distance. Fan leaf temps should fall somewhere between mid 70s to 80. Some plants can perform well with leaf temps up to 85-90, but 75-80 is a good spot to be in.





Hope this helps.

It is based on heat at top of canopy. The cool tubes allow higher lumens by venting the heat away.

24" on 600 is a bit far

16-18 is my go to.

There is a such thing as too intense light.

My rule of thumb would be: if you held your hands at height X away from the bulb, would it be comfortable?...if not then increase the distance away from the bulb, if so then would I find best distance where by iteration.

If it is too hot for your skin then it's too hot for the plants.

As, one poster put it, err on the side of caution, but keep in mind that light intensity is inversely proportional to the square of the distance away from the source.

I just use my hand to, but people have been a bit more scientific and used non-contact thermometers, looking for leaf temperatures below ~34c

The depreciation math is a right mouthful, but doesn't apply. The $10 thermometer is good though.

I've run bare bulbs vert, enclosed hoods, kool,tubes ....I have a little experiance with this............it's dependant on the cultivar and the environment ......you can get fancy and grab a light meter and really get a clue for this....or you can do as the poster said above errr on the side of caution .....
I just put the canopy tops in direct air flow and tried to keep them as close as possible
Then again I'm using all screw in LEDs now instead of my old hps bulbs....I hope u find ur sweet spot man!

Del_9_THC said:

My rule of thumb would be: if you held your hands at height X away from the bulb, would it be comfortable?...if not then increase the distance away from the bulb, if so then would I find best distance where by iteration.

If it is too hot for your skin then it's too hot for the plants.

As, one poster put it, err on the side of caution, but keep in mind that light intensity is inversely proportional to the square of the distance away from the source.

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i kept my aircooled 600watt 18in away from tops.i could hold my arm underlight and it felt
ok