LEDgardener

hi all, brand new so forgive ignorance.

built a light with 4 qb132's driven by hlg-185h-c1400b and 4 qb120 driven by hlg-240h-2100b. I'm not using any dimmers. currently have plants about 18-20 inches from light and I'm seeing some signs of light stress (curling leaves-- not burning yet though).. any recommendations on distance. also, since this is first built, any suggestions on how to improve light, etc.

thanks all

Hey dude, welcome.

How big is your space? How old are your plants? Usually 18-20” is the sweet spot.

4x4 space. Its a tent, I have about 6.5ft of overhead space to play with. plants are about 4 weeks old

q: should I be running a dimmer? or 18-20 on full juice

thanks for your help

Play it by the ear.

Minor leaf curling in veg shouldn't bother you too much (like minor over-feeding), as long as you have it in check and it doesn't look like it's getting worse.

Same thing when going to flower: start at a safe distance (12"), then lower until the plant looks stressed.

What normally stresses plants is not the light but the heat emitted by the light. I'm now at week 4/5 of flower and the lights are 2-3" away from the top of the canopy, and they seem to be doing just fine. I might raise the fixture a bit soon, but at 28°C (top of canopy) my plants look happy enough.

welcome to the forum first off

personally I like higher distance in veg.. like GML, ( was on YouTube now his own site )I noticed very sluggish/minimal vertical growth when I ran anything under 24" at full power. ( 4 qb 288's on a 480w driver over 4x4 scrog in 5x5 tent ) the plants acted like they were getting enough or too much light and just stayed where they were at. they bushed out but not up. and that was even sluggish.

now I run 28"-30" in veg and drop that to 16"-18" in flower... while playing with different heights over the last year I'm figuring out I can control a lot of the stretch.. most stretch % are cut at lease in half. I can flip your average stretch when they just hit screen level and crowns end up just above it. or if it's a lanky girl flip 6" or so under and it ends up around the same height.

I'm probably the odd ball of advice on this one... but it works for me.. trial and error to see what works best for you!! and again welcome!

steelcitymadman wrote: ↑

Thu Jun 07, 2018 7:50 pm

hi all, brand new so forgive ignorance.

built a light with 4 qb132's driven by hlg-185h-c1400b and 4 qb120 driven by hlg-240h-2100b. I'm not using any dimmers. currently have plants about 18-20 inches from light and I'm seeing some signs of light stress (curling leaves-- not burning yet though).. any recommendations on distance. also, since this is first built, any suggestions on how to improve light, etc.

thanks all

I'd start off further away maybe, as JGG said. Though you're not using QB 288's.. so I duno for sure about the intensity difference :/

Do you have an IR thermometer? Measure the temps of the canopy (the actual leaves and/or buds of the top of the canopy).

And if you have an android (maybe iOS has this too) you can download a lux meter, and though Lux isn't the best indicator for plant usable energy, you can use the numbers for reference of a difference between different hanging heights.
Just a suggestion.