First grow, ~4 weeks into flowering.. possible K deficiency or cal-mag?

[TNToothpick]

Not a K deficiency that I can see. What's the feeding watering history. They do look over fed and transpiration is not looking great. So some info on all the grow room conditions would also help.

Kinda looking like nutrient buildup issue, watering, root issue... Something like that.

Any foliar sprays?

No foliar sprays. I have fed them three times now, first two feedings were very light feedings. I noticed a little nute burn so I went back to water only for a few feedings then noticed the yellowing leaves and clawing so I have those few plants some nutes thinking they were hungry. That was 2 days ago. Grow tent conditions are 65-78 degrees or so night/day, Rh @ ~45, constant airflow. Strange that only 2-3 plants are really showing the leaf yellowing/brown spotting. I haven’t tested runoff ppm yet, just got my meter in yesterday and will do that next watering.

 

[Aqua Man]

Not true. If ocean forest is not overwatered you can meter the ec and know when to feed. I did it (and never tested ph during the grow) successfully for 5 years.

You have a lot of experience in your medium and the ppm and how it's reacting. But I do remember a ph issue and some challenges correcting it if I'm being honest. But I have no doubt you can read the ppm of your grows to know when they nutrients are being depleted. But I don't personally feel you can accurately read the ppm of organic to diagnose over feeding.

Overwatered? I'm not sure I commented on that.

As far as ppm instead of going back and forth this explains it pretty well.

PPM and You: A Quick Guide | BlueSky Organics

While we try to make cannabis growing as simple as possible, some technical terminology is just unavoidable. Lately, we’ve had many novice growers ask us to explain PPM, TDS and EC readers, and how they all work together to help you grow better cannabis. Understanding these concepts isn’t the ea ...

blueskyorganics.com

 

[Aqua Man]

No foliar sprays. I have fed them three times now, first two feedings were very light feedings. I noticed a little nute burn so I went back to water only for a few feedings then noticed the yellowing leaves and clawing so I have those few plants some nutes thinking they were hungry. That was 2 days ago. Grow tent conditions are 65-78 degrees or so night/day, Rh @ ~45, constant airflow. Strange that only 2-3 plants are really showing the leaf yellowing/brown spotting. I haven’t tested runoff ppm yet, just got my meter in yesterday and will do that next watering.

So they are likely over fed a bit and the RH will cause them to take up even more nutrients. If you can get the RH up a bit and stop feeding any added nutrients I think it should help

 

[Aqua Man]

Yeah we are discussing. Not trolling or arguing. Even though you are wrong! :-)

Lol it wouldn't be the first time I'm wrong.

 

[TNToothpick]

So they are likely over fed a bit and the RH will cause them to take up even more nutrients. If you can get the RH up a bit and stop feeding any added nutrients I think it should help

Ok I will do that and see how it goes. Thank you, your advice is very much appreciated. I was afraid to add any nutes because I have read ffof has plenty out of the bag, but since I transplanted and went straight to flower I wasn’t sure how long I had before I needed to start feeding, if at all.

 

[Aqua Man]

Ok I will do that and see how it goes. Thank you, your advice is very much appreciated. I was afraid to add any nutes because I have read ffof has plenty out of the bag, but since I transplanted and went straight to flower I wasn’t sure how long I had before I needed to start feeding, if at all.

The plants will tell you. It's easier to correct underfeeding than over feeding. No matter what you grow in.

 

[MIMedGrower]

Ok I will do that and see how it goes. Thank you, your advice is very much appreciated. I was afraid to add any nutes because I have read ffof has plenty out of the bag, but since I transplanted and went straight to flower I wasn’t sure how long I had before I needed to start feeding, if at all.

As an average figure about 3 weeks before depletion. You would see the leaves thinning and losing their shine and maybe low leaves fading a bit. Then its time to start low like 15-25% of directions.