LED Lighting guidelines

[MCfifty9]

I'm pretty much a newbe at growing weed. Since I am just starting an indoor grow spot, I am wondering if there is any documentation regarding the distance an LED lamp should be from new growth?
That is, a relationship between the wattage of the LED and the distance to a plant? I purchased a HLG 100 and the documentation that came with it is next to none. Any suggestions would be greatly welcomed.

[Zooter]

I have HLG lights. Call their tech line or email them. Their techs are very helpful. They suggested downloading an app on your phone to measure PPFD. HLG, has suggested light levels for each growth stage on PPFD
Their lights are better for later veg and especially flowering

[Gingerbeard]

I have the 360 Elite. You're right on the lack of information from HLG. I remember having to surf a little to find the answers. Even had to find an assembly video to put it together.

Edit: Horticulture Lighting Group HLG 100 LED Grow Light Review – LED Grow Lights Depot

[3Berries]

I've gone through a few years of the college of hard knocks with growing and LEDs. Ran for 4 years or so on 3 home made 100w cobs. Might actually graduate this year with a healthy plant to the end.

But I've found the Calcium needs are very important when using strong LED lights, I also have high CO2. I've always had some yellowing on new growth as the plants progress out of veg to flower and though flowering. But not this run, only on the tips. When I see the yellow tips I give it a top dressing of CaCl2. The LED bleaching IMHO seems to be a nutrient deficiency.

Basically the LEDs can be pretty powerful and the plants can take it as long as you feed them right. What I see now from too strong of light is canoeing towards the end of the light day. I just lowered then all yesterday as they are taking it quite well.

I have a cheap LUX meter. Outside on a sunny day at noon it goes over 100k LUX. So I run the lights around 35k LUX at the tops. But the wattage makes a huge difference as far as distance. I use 50w, 65w and 100w square LED fixtures. I use the 50w one for temp control too to boost the temp in the winter keeping the tent between 75f and 80f.

But don't get discouraged as even not so healthy looking plants can give some decent yields.

[Zooter]

The HLG lights have red diodes which are great for flower. Info I got on mine, 600rspec, is the distance from the light should be 48” for veg and 36” for flower. Converting Lux to PPFD is not really accurate. I recommend the app for your phone, according to HLG, it reads about 50 units lower than it actually is.
Hope that helps 😎

[SoOrbudgal]

That may be a very good brand but to me it's not enough draw from the wall for a large tent or more than 1plant if that. Less than 100watts from the wall from what I've read ?

[Ckbrew]

The thing with LEDs is that there is no "standard" for output, so they all tend to be a little different. Do the heat test with the back of your hand. Place your hand under the light with the back of hand facing up. Start low beneath the light and slowly raise you hand paying attention the the heat you feel. As you raise your hand, the heat will slowly increase. At some point, the heat will start increasing at a much faster rate. The distance the heat starts increasing fast is your approximate minimum distance from plants. For my SF 4000 that winds up to be about 15 inches at full power. Keep in mind that watts pulled from the wall is also important.