m0useanswered grow question 2h ago From my understanding Cannabis plants can take a beating of light right from the get go. Like 40DLI range, its a trooper.
Switching up the main light, via indoors to outdoors or small light to big light they need a bit of time to adapt as their leaves are optimized for something else,
its like stacking on a bunch of weights when exercising, you where doing 100lb now its 350lb gotta work your way up to it.
Best way to harden them off is small exposures to the new light, 1-2hrs in rising sun and then shade for the afternoon and back inside for night time temps, not full blast afternoon sun at max intensity "indoor to outdoor" or gradually increasing the intensity of the lights, dim settings from 10-20-30-40 exct "indoors".
Eg if your small light is only giving off 300 umol/s/m2 and the big light is hitting 900 umol/s/m2 then dim the big light down to around 350, and then work its way up. go up 50 a day if possible. or 10% dim, maybe do it every other day, play around with it and make notes. note that the closer the light is to the leaves the strong the light will be. eg. seedlings 30" away will be getting far less light intensity then plants 10" away so might need to use a mini table if its mixed in with existing plants. Most lights are optimized for a hang height of 18-25", not to many hot spots and good PPFD maps.
Last note the photoperiod should also be similar or match. If seeds are at 12/12 for example and new light is 24/0 its a big shock. lower it down. or boost the old one up. Could also increase the intensity of the small light or move it closer to really get it stronger like the new light.