hi guys, posted a couple times about this and i'm trying to pin point my problem, before i get into details here's my grow info: -room temp 78-84F 40% room humidity -sealed room 1650 ppm co2 enrichment -i'm using 50/50 coco/perlite (small cup -> 1 gal pot -> 2 gal smart pot) vegging in a tent under a 8 bulb T5, flowering under 1000w hps nutrients i'm using h3ad 6/9 gh flora 1/2 tsp epsom per gal at 5.6-6.2 pH, i use some great white for mycos, when i flower i use 5ml per gal floranectar for my sweetner, humic/fulvic acid, an big bud and super natural bud blaster for my bloom boosters (some say too much stuff but 've used same mix with great success before at a different garden), i'm topping at 2.4 ec (1200 ppm .5 tds factor) -flooding ebb flow 4x4 trays, 9 plants per tray -1500w of hps lightning per tray, flooding twice a day lights on and off for 10minutes -gdp indica strain very short, topped and trained w/ scrog screen ok, so basically i'm vegging in the tent for about a month from cup to 1 gal then to 2 gal, and throwing them under 1000w in my flowering room, first problem i had was i had yellowing i think due to the plants not hardening off and the leaves would yellow and die and new growth would come out (i'm going to raise the lights much higher, and do some premeasures to harden them off with a 600w in the tent), but my last run, after they healed from the light stress from the 1000w they got green again and i flipped them but after i flipped them all the fan leaves on my plants started yellowing badly and i thought maybe they would get better (they looked hungry) but they just got worst and the leaves started dying off, im trying to determine if my problem is: -plants are not getting enough nutrients, or plants are getting overfed -light stress continued after they healed -minor alagae buildup causing pH to not stablize causing nutrient def/lockout -roots in pot have outgrown the pot causing buds to suck all the nutrients from fan leaves -nutrient defiency ranging from N def, Mg def, and even P def with so many symptoms i'm thinking its a pH problem (but i'm trying to keep pH at around 5.8 in the rootzone) the buds themselves look ok, but i'm guessing they would've got much bigger, and im thinking its going to cause me problems my last few weeks of flowering when they're suppose to be getting yellow, effecting my yield thanks for reading my long post and hopefully i can get some good advice/input on what i can do to prevent this from happening again.
Just briefly looking in here. Looks like the pots are to small to me? Coco isn't really my thing but those leaves don't look burnt. I would also agree that you seem to be feeding high. Those leaves in the photo's aren't nutrient burn, they look yellow and soft, not burnt and crispy. Obviously couldn't be underfeeding by high levels of nutes, why do plants look underfed? Pot size for whatever reason, longer veg time, starting from seed with larger tap roots, any number of slightly different variables. Looks hungry but no real signs of nute burn or under watering from what I see. Hard to over water coco. Roots outgrew your pot buy just a little.
A picture would be awesome. Your leaves turn yellow when they lack nitrogen, if you add just a little bit of nitrogen to your watering you'll get a much deeper green colour (Don't over do it). When a cannabis plant starts flowering it will suck out all the nitrogen from the fan leaves and use it to produce buds, all plants do this this and it's nothing to be afraid of- it's how it is. My guess is because the 1kw has been close to the plants they've been growing really fast and therefore haven't been able to keep up with nitrogen. It does not sound like you're overfeeding them
Not a nitrogen def. It's calcium def. CALMAG PLUS @ 5ML/GAL. Sent from my ADR6400L using Grasscity Forum mobile app
Calcium form a bond with the coco fibers, making this unavailable to your plants. (the coco will outcompete your roots, until the coco fibers are saturated) You must saturate the coco with extra cal-mag to make it more available to your plants. I would use cal mag in every feeding veg through flower, up until flush. Additionally, I would suggest using half grow nutrient and half bloom nutrient in the first week or two of flower. It's normal for your plants to yellow near end of life, and I believe this makes a better quality product. The buds end up looking brown and ugly, even though it tastes much better, most people think good weed has to be green. Great job otherwise!