Still hoping to find definitive answer to discoloration of leaf tips and pistils. I am hanging two ViparSpectra XS-2000 lights. Initially they were hung (for a short while) at 18”. PPFD map in manual states at 18” and 100% PPFD is 830 at center for one light. I raised to 24” after noticing pistils on one strain turning reddish-brown 18 days after switching to 12-12. They are nearing the end of 4 wks.
I grow in FFOF. I am careful to not overfeed.
—2ml Atami Bloombastic/gal r/o water every other day. Started this beginning of 4th week
—5ml CalMag plus/gal r/o water 1-2 times/week
—5ml Snow Storm Ultra 1-2 times/week
—water every day; water without nutes every other day
No vegetation N based nutes since first week of flower.
—Alternated “Flower Fuel” and “Kool Bloom” weeks 1-3. Administered every other day
My feeling is that I placed the two lights too close initially but am not sure. Certainly there must be a way to, at least roughly, using a PPFD map for one light to figure the closest distance one can hang identical led lights considering overlapping fields of two separate lights. Come on you photon geeks!
Normally leaf tips burns are attributed to nute burn.
I have 5 gal pot 4 pots, they only require water their whole duration. Shouldn't ever have nute burn, yet I have on all my plants.
Great for autos.
Never had over watering issues since 70s, then again 6 in pots and sog with automated water systems and now leds and hand watering. I use the feel method for determining watering, will pay attention to more closely. I never remember leaf burns from mh and hps lights from water droplets on the leaves, but leds magnify those droplets and will leave a spot.