How close can I put my HPS?

I have a HYDRO FARM HPS system with Tempered Glass. How close can I put my HPS to my plants? I have GREAT ventilation and I want to get those plants as close as possible, they are currently 18" from the light but I think they can be closer...

You can have it low as you can as long as the heat of the light won't burn the leafs. The best way to do that is making sure you using a air cool vent plus nice fan to keep it cool. Then you need a small outside fan to blow on the plant itself. This method will keep the plants cool.

Put your hand between above your plants and hold it there for 30 seconds. If it not doesn't become unbearably hot than it is safe your plants.


JJD

Yep, he's got it, rule of thumb, if you can hold your hand at the top of the plants without feeling pain, then that's a safe distance.

I have moved my HPS from 18" from the top of the plants to 12", HOPEFULLY I SEE SOME POSITIVE RESULTS IN THE GROW!

Is 80 degrees a good temp for my Bubble Gum Clones in their 4th week of flowering?

80 degrees should be okay, but 70 degrees is optimal.

dont go much over 80 or u might be entering dangerous territory.

what happens if it's over 80?

NorCal510 said:

Is 80 degrees a good temp for my Bubble Gum Clones in their 4th week of flowering?

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About room temps It depends heavily on the strain but 80 degrees is perfect,the reccomendation of 70 degrees is way too cold & your plants will experience a slowed growth pattern.

For the distance between the light & the canopy you should not go by the feel no pain method as it is not allways a true indicator & can roast the shit out of the canopy & damm fast too,once its roasted there is no going back,you should get a $5 old school mercury thermometor from home depot & hold it flat on top the canopy surface for 5 minutes,this will give you an accurate reading of surface temps at the canopy.

Keep the surface temp at the canopy at 80 degrees or a little less & your good to go safely.

NorCal510 said:

what happens if it's over 80?

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Again its strain dependant,the problem is that after 80 degrees your pushing it into the red line,the strain may be able to safely take 88 degrees but without knowing for sure its safer to stay at 80 degrees or a little less.

Well the strain is BUBBLE GUM

NorCal510 said:

Well the strain is BUBBLE GUM

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You should research bubblegum & see if there is any pertainent info regarding weather it can take high heat or not,maybe shoot an email to a breeded of the strain ,or the seedbank you bought the seeds from,i dont grow that strain so i'd only be guessing.

i always thought 78-82 is good temps to stay between i live in 100+ weather so 80 is pretty nice

I have a 400w hps with a HTG euro hood that has glass and air cooled. I pull air off top of plants through hood and out, with 2 50cfm fresh air blowing across tops. My temps stay at 77 at canopy top (though this is digital and maybe should also check "old school") I am 12" from light, I get occasional browning on the very tip of new growth. Not enough to really hurt, so I would not go closer than 12". ***I can hold my hand much closer without pain.

If you are able to adequately cool your lights, you can move them down quite close to the canopy. My plants are under two sealed, air-cooled 600w HPS systems. I am able to keep my lights 4"-5" from the tops and still maintain a canopy temp of 77°F.

rolla8 said:

If you are able to adequately cool your lights, you can move them down quite close to the canopy. My plants are under two sealed, air-cooled 600w HPS systems. I am able to keep my lights 4"-5" from the tops and still maintain a canopy temp of 77°F.

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4-5" from the tops with 600w if they aint burning nice work man

Wretched420 said:

4-5" from the tops with 600w if they aint burning nice work man

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Yeah, I was actually quite surprised I was able to get them that low without issue. My two lights are setup "inline" with a 465cfm blower pulling carbon-scrubbed air from the room through the hoods and into my house's chimney. Like I said, with this setup my canopy temps never go above 78°F, which is only 5° higher than the ambient room temp.

nice dude! I moved mine from 18" to 9" and the temps stayed the same. I have even noticed better and more efficient growing buds over the past day

There is definitely better grow over the past few days, PLUS I added some BAT GUANO because my leaves were starting to YELLOW due to lack of Nitrogen. 4 more weeks left on the grow, should be great!