Zeus pro 600w light distance

Hi,

I have been having really bad issues with the sides of my leaves curling up. Everyone is suggesting heat or light stress. I was told in the shop I brought them from that 40cm from the top of the plants would be fine..I’ve just raised them tonight to 75cm as they really aren’t looking healthy, would this be to high? I’m 3 weeks into flower

40cm is too close, 75 more like it. Don’t worry too much about getting the lights in close like some books suggest, lumens etc. Diagram showing light intensity loss in relation to distance. It’s better to maintain a slightly more gentle environment to get great tasting quality smoke. The terpenes within the resin will be damaged when too close to lights and will lack flavour, etc. Besides that when a plant is stressed you should higher the lights and keep a slightly higher humidity level above 60%. Leaf curl can be caused by a combination of high nutrients, heat and low humidity also. The environment counts for a lot, buds will swell even when quite far from the light to a certain degree. Humidity has a lot to answer for.