LED Experience Needed


I have two galaxy hydro 300w LED’s. Both are a consistent 135w true draw.

The manufacturer recommends 48-56 inches height at seedling stage (40-48 for veg and 24-36 flower). This seems way too high for the amount of heat coming off the lamp, to me.

Any experience out there with these or similar lights? Thanks very much.

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that does seem rather high… @Screwauger a small t-5 works great for seedlings to at least four nodes… that is if you can afford one, you can never have enough grow toys! lol

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I have 2 vipraspecttra 450w (180true), and I keep mine about 16 to 20 inches above canopy, and haven’t had any issues yet (Note that I have dimmers and can adjust the lights for seedlings). I would start at 24 or 30 inches, and see how the plants react, and adjust from there accordingly. And keep notes, so next grow, you can just use what worked last time…

manufacture probably inflated the height to be able to claim a bigger footprint…


Thanks very much @BIGE and @Ron330

I have them at about 36" now and plan to lower a few inches each day.

Wondering if in translation, that should be centimeters in the photo? For the amount of heat on the back of my hand at 4 inches i would think they could be fairly close during veg and flower but I dont want to risk my little babies.

I do have a nice t5 set up in my amazon wish list but thats down the road a piece.

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with LEDs it is not the heat you have to worry about, more so the power/strength, as LED penetrates a lot more than a normal light. You end up getting a burn from the light, instead of the heat. There is a long technical explanation, but I can not find it at this moment, but that is they stay at a set distance. To close can also cause bleaching and weakened THC…


That makes sense @Ron330 I believe I recall reading something similar to what you note. I am going to be cautious and having just checked, the light is 31" above the plant tops right now. If I went 48 inches I need to re-configure my set up lol.

Make shade. I have fake plants I put over seedlings so they don’t get all stretchy.


I have the no name cheap led light from ebay and I have a 1200w light at 12" from plants. This light claims 180 true watts but I got a meter and it is only pulling 120w out of the wall. I have got the lights to close before and you will see bleaching if you get your light to close. It looks like the tips and edges of the leaves get a white frost color to them. Also be careful of the one UV led that most lights will have. If you get that to close it will sun burn your leaves so rotate your plants so the UV led isnt over one spot on your plant.
Happy growing.


I very much appreciate all of the input. Thanks VM.

Thought I was going to be able to take decent iphone pics through my LED glasses but that didn’t work :calling:

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One thing I am not is patient. I’ve checked the tent about a dozen times since this thread started. I’ve monkeyed with the light and have ended up at 24" and I kid you not, the plant look like they have grown have an inch up and wider than when I started the LED. I’ve been itching to play with my exhaust fan/filter and when the temp jumped from 70 to 74 I put it on low. Light is on from 5am-11pm and I rigged fan to go off with light. Looking good so far and I gave them a little sip of 1/4 strength cal/mag, superthrive and GH nutes this evening. PH 5.5-5.8 as i have no meter just the drops

Thing about leds is it’s not about heat, that’s HID lights, with leds it’s harder to measure because surface temp isn’t good enough due to the intensity of the lasers being the issue when too close (or something like that) however that does sound way too far, try 3 foot or even 4 foot for seedlings, they need next to no light to get sprouted, if they stretch majorly just bring the light down, worked for me anyway.


I’ve arrived at 18" and have 2 of 3 300w led’s going now!! My ladies seem to love it and the RezDog recipe!