Details below. At this point I’m thinking magnesium maybe? Danged If I know. At this point it has appeared on just a few branches, so where it’s happening its hitting hard but most everything else looks fine. Pics below of one spot and then a wider view with that spot roughly in the center.
Nutrients or fertilizer system used. Jacks from start. 3.8/2.5/1.0. Tribus, Recharge, and Lumina once per week.
What type of lighting are you using? LED, HID (MH, CMH, HPS), or Fluorescents? Spider Farmer SF4000 running 18/6 and an HLG UVA bar running 12/12.
What are the temps in your growspce? Day / Night? low 70’s lights on and mid 60’s lights off
What is the RH = relative humidity in your growspace? Day / Night? 54-ish round the clock
AC, Humidifier, De-humidifier? Dehu in the bedroom, set to and maintaining 40%
Do you have a Ventilation system? Size? 4", 6"? AC Infinity S6 with Controller 67, venting into the bedroom
Co2 Yes / No? No
How long have you been growing? 2 months
The problems are pretty much limited to the two plants that are farthest into flower, with the other 3 looking maybe a week behind in development. At this point I’m thinking magnesium, either from not giving enough or because of a Ph based lockout.
Remedial actions thus far: Upped the Ph on the last feeding to 6.0, and upped the mag in the mix to 1.2 grams / gallon. I think I’m done with the Lumina for a while. Pain in the rear to mix and starting use was the only real change I’ve made in the last 2 weeks.
I had a similar issue with my blue dreams. Had 5 in a rdwc system and one of the girls top leafs started get brown spots and patches towards the end of flower but none of the others were showing any signs so I just assumed that one was more sensitive to the pH change than the rest. If pH is good and steady then I would assume magnesium deficiency too. Hope its a quick fix either way and good luck with the rest of your grow!
You could be looking at one of three possible deficiencies either magnesium or potassium or phosphorus ,here is something that you can try it will take care of potassium and phosphorus and magnesium ,get ur self four bananas peel the bananas cut the peels into smaller pieces place in a mesh bag or stocking place in a five gallon bucket of water and add a tablespoon of epsom salts to the water and add two tablespoons of molasses bubble it for 24 -30 hours and then feed ur plants this has magnesium and potassium and phosphorus and calcium with a little bit nitrogen and iron
@PurpNGold74 - Can I impose on you to give me your quick thoughts on what might be going on? In retrospect, I probably shouldn’t have posted the question in the middle of the play-off game.
Damned if I know when it started. I noticed it Friday, and it looked like what you see. Could have happened earlier in the week, though. It hasn’t gotten worse or spread elsewhere, and you can believe I’m eagle-eyed now. I’ve upped the Epsom to 1.2 g/gal from 1.0 if it’s lack of mag and bumped the Ph from 5.8 to 6.0 for if it’s Ph related.
Up until Saturday I’ve been Ph-ing to 5.8. Saturday I bumped to 6.0 and measured run-off at 5.9. I don’t think I’m way out of whack, but maybe just enough.
Too many years in manufacturing for me not to calibrate my measuring devices on a regular basis. Except tape measures. I’ve yet to see one that had the tick marks slide down the tape, no matter how long you leave it sit on the same side.
I agree you’re not out of whack at 5.9 PH it’s not a deal breaker. I like to keep a fresh clean bottle of 7 ph solution just to verify my meter occasionally. If meter reads 7 PH no reason to calibrate.
I’m still looking pretty squinty-eyed at the Lumina right now. I started using about 2 weeks ago, and that stuff absolutely crashes PH when added to the mix. May just be coincidence, but the bottle’s staying in the chem-cabinet for the rest of this round.
