White Spot Main Colas

The second, greener image is a textbook picture of light stress (not heat). I know this because I had a FB White Widow auto that did the same under too much LED. It almost looked like snow/dandruff of the leaves. Mint colored leaves too, harder to see when the lights are blurple. I'm no pro, but that's my take. Lights up! .... or.... Plants down!

Hey, @OimRausch! It is almost impossible to burn them since the temperature at the top is 23ºC. You are 40 cm away from the lamp ... so that's fine too (at least in terms of warm-up). I think it could be one of these 2: 1 - PAR is high. Using 250w + 125w gives you 375w of LEDs. Maybe they are having too much light. They must obtain a maximum of 900-1000 micromole of photons per m2 (as you are not giving them extra C02). You can check it (more or less) with an application called «Lux Light Meter» and adjusting the value depending on the color temperature of your LED. 3500K spectrum: Divide the app reading by 1.4 for precise lux Divide the app reading by 100 for PAR . 4000K spectrum: Divide the app reading by 1.25 for accurate lux Divide the app reading by 90 for PAR . HPS spectrum: Divide the app reading by 1.2 for accurate lux Divide the app reading by 90 for PAR More of this: www.youtube.com/watch 2. If they are having a great thermal contrast. ¿Is your fan putting in so much air? Its too cold?. If the answer is no, you should check the first point (about light intensity). I really hope I have helped

I second what Shagrath said, I think it’s the height of your lights. My tallest plant(Pineapple Express) is doing the same thing right now and there’s nothing I can do... I supercropped her, double ScrOGed her and she’s still too tall. I’ve just resigned to having a few colas that have bad light burn, my tent won’t allow me to move my light up further at all.

Hello! How far is your lights to the plants? Did you know that light stress can happen even in low heat conditions. Leds produce so strong light without heat that it will bleach the buds if kept too close.