Man that picture makes me wanna say you have possible light burn, because I see the necrotic spots on your leaves and the plant as a whole looks very healthy. A little chlorosis in the leaves, but I think that's just early stages of light burn. You just switched to flower so this damage I see may be from your veg cycle. It's common with LED's because the lights run for 18/6 instead of 12/12. If the light intensity is too much it's too much for 6 hours longer each day. Those lower necrotic leaves could either be lack of light and be nothing of significance or another issue. Probably just lack of light which is very common and natural. Personally I don't add any epsom in veg with the 321 system. Jack's 5-12-26 has 6.3% mag sulfate. That's a lot. However, I do add it in flower for the extra sulfates. Also, this is when your plants are the largest and have the largest nutrient demands of their life cycles. I just don't feel it's necessary in veg.
12" is very close for a high output qb. I would raise the light to 24". After flower set at week 4 I would look at lowering it back down to 12". There's no point in showering the plant with too much light in week 1-3 of flower. You've got delicate fresh flower sites forming and they have no need for extreme intensity. Once you've developed some healthy flowers by week 4 it's time to crank up the volume until you harvest. Those flower sites at week 4-harvest will need all the flower power they can get.
That is not "light burn".
i think it's probably both...
After omitting the epsom your recipe is nearly the same as mine. I hold 32 gallon reservoirs but when weighing the A and B I always pretend as if it's only 24 gallons to hit my target ec of 1.3-1.4. A tip for maintaining proper temp in your grow space when growing with LED lights is to buy an elecrric oil filled radiator. Usually $40-$50. I fucked up a bunch of plants before I put the heaters in. I was running temps between 70-74 and the plant's metabolism slows to a crawl. The leaves sweat off moisture at a much lower rate and drink less at the root zone as a result. Boom! I started seeing all sorts of strange shit happening to the foliage that made no sense at the time. They basically weren't drinking fast enough to consume the nutrients they were given. Instead of watering every other day as per usual with my t5's I was only watering once every 3 days. I learned very quickly the only flaw with LED lights is they are so dam efficient they often do not provide enough heat output to keep the grow space at the ideal temperature (78-82F) which causes the plants to basically starve. To complicate matters further the plants are being showered with more light than they can use. Chlorosis and necrotic spots develop. I often hear the myth that won't die that LED grown plants require more mag and calcium. Horse shit. The plants need heat in the right range to grow properly. Supplemental heat. Problem solved.
Thanks, i was considering weighing nutes out for 80L instead of 100L for next grow, as i seem to be diluting it every res change anyway. I'm moving into flower now, just past day 21, i figured may as well keep the current measurements as I'm sure they will get hungry soon.
Those were my findings as well. Unfortunately in the winter all of the heat that I have to add into the system almost completely offsets my electrical savings vs. HIDs. Right now in the hotness of summer the efficiency is great though.
You are on point sir. I'm saving 2 of my 1000w lamps for winter growing to provide heat and some nice flower power. Otherwise I'll have to run a heater in the room. That puppy is 1500w and doesn't add any light to the room. Might as well get some lumens and heat at the same time by running a couple HID's. I'm planning to mount the 2 1000's right in the center of the room where they were before flanked by 2 660w qb's in the front and rear of those. Overkill? Nah
was wondering if I could pick your brain again, after following your instructions, almost a month ago, by raising/dimming the light the problem went away. I now seem to be having the same problem, day 36 from flip, they are now 14" from the light (sf2000) with is at %55 power. I've got a few similar pics over the last week that show its getting slightly worse. I'm happy to provide more details/ photos. Just didn't want to mess with your thread too much. Thanks