vegging light for 2x4. Limited height.

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PLantAsEED

PLantAsEED

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I built a veg box (57"W x 19"D x 48"H). I built it with limited height due to recieving (2) 4'-2 bulb T12 fixtures for free and planned on keeping the light very close. I am vegging most plants anywhere from 4-7 weeks. and keeping the light mere inches away from the plants. I have some that are about 5 weeks old and they are growing very lanky and have far node spacing. Any advice on how to shorten node spacing and grow stockier plants, or any cheap lights to use?

I am considering 2 - diy cob fitures at around 40-50w each. But concerned with height limitations as I have heard that they have to be 30" away from the canopy, same as QB.

Will things tighten up when I send them into flower under quantum boards?
 
PLantAsEED

PLantAsEED

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A few reference pics. I have only every grown under HLG QB132 240w. So everything could be fine and things could turn out top shelf. Limited experience. why I am here.
 
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FlintTownBrown

FlintTownBrown

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If your height is limited and you need the light to be close to your canopy, COB isn’t your best choice. They run alot hotter than other LED options, and because all the light comes from very few diodes, there’s not enough spread to cover your canopy when the lights are close. Low powered QBs or LED strips are the best bet when your height is limited. These allow you to spread the light (and power) over the whole canopy, and they can run cool enough to put just a few inches above the plants.

The HLG QB120 (max 70 watts in a 9x11’ board) is a good option. If for veg only, the 4000k temp version is a good choice. If for veg and flower, go with the 3500k...more reds and better all around spectrum for the whole lifecycle. You can get a 4 pack for $132 and if you ran them at 60w ea you won’t need heat sinks.

The bridgexlux EB series Slim gen 3 strips are likely your best bet. They’re newer technology than qb120s (which are a few years old), pretty cheap, fairly efficient, and there are many mounting options. You can run them naked (no heat sinks) if you give them only nominal power (700mA, or about 30w each for the 4’ strips). In your space I’d get 8 of the 1190mm (46.8”) strips and power them with a meanwell hlg-240h-48b. At 30w/strip the temp of the LEDs is barely warm to the touch, certainly cool enough to put a few inches above the canopy.

heatsinkusa sells 0.601” wide heatsinks 48” long for $4.32 ea. Even if you don’t need the protection, the heat sink provides one solid way to mount the strip to a frame, as well as peace of mind if you do crank the power.

my veg area is much like yours...2x6’, 40” high. I have 25 of the 590mm (22”) strips powered by an hlg-320h-24b. They’re mounted with zip ties to 2 lengths of 3/4” conduit running the length of the shelf. It looks like hell but is perfect for my space and allows me to move the strips around to focus light where needed most. These cc/cv drivers are great for this kind of application because the voltage stays constant, with per-strip current decreasing with every strip added to the mix. (I.e., I could run just 10 strips with that 320w driver, but each strip would get 32w, run much hotter, require heatsinks, and could only get within 8-12” of the canopy before burning). Right now I have plants <2” away with no ill effects. These 22” strips may be too long to fit width-wise across your box, which is why I recommended the 47” version, running lengthwise.

the “B” versions of these meanwell drivers have wires for an external dimmer (potentiometer, aka “pot”). The “A” versions have a built in dimmer but you need a small screwdriver to turn it...not convenient, so I choose “B” and add a pot I can mount wherever convenient.

Your plants don’t look terribly lanky, but are likely reaching for more light than those t12 bulbs can provide. You can definitely veg with CFL but unless you use ALOT of them, they just don’t push the energy you get from stronger sources like LED or HID.

wow That’s a lotta words. I hope this helps.

Here’s a pic of my setup:
EB3B892C E26C 47D0 B777 263A3E9EA226
 
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