Leaf problems...Help!!

[Daiseysue]

This is my first grown on my own. I have assisted a friend before. I have a few photos growing... juicy fruit, train wreck, amnesia haze and a purple haze. I have done some LST and thought I was ready to flip to 12/12. The odd leave has shown signs of something but I wasn’t overly concerned. Today I have noticed increase yellow/ brown on several lower leaves on a few plants. And the tips changing in a few as well. I have started decreasing the lights 2 days ago. Just on 16/8 right now. I have them in 5 gal fabric pots in promix HP. Under 2 550 California Works solar system lights. Temp set at 76, humidity varies but try to keep around 50%. Use GreenPlanet 4 part nutrients and always add calmag to it. Rotate between water / nutrients. I try to keep the PH between 6.0-6.4. I have not had good run off as I felt I would be over watering the plants ?? Any thoughts??

[Smokesteve]

https://www.growweedeasy.com/cannabi...h-fluctuations
I consider a soil slurry test as well.

[dilvish]

likely a combination of PH issues and the soil mix with nutrients. typically soil does not require cal/mag. It looks like nutrient burn.

if you are not getting any run off with fabric pots then there is a problem with your watering. try to get those pots off the floor or catch tray and have some air beneath them so they are not sitting in water as they will reabsorb it. recalibrate your PH tester an do a good flush with properly PH'd water.

Turning the lights down won't solve this issue and at 76F the soil isn't going to dry out very fast so you should not be watering more than 3-4 days at a time.

P.S. Pro mix can be a bad choice as I've seen many people have issues with it.

[Daiseysue]

All the plants are off the floor with catch basins underneath. I’ve just have never watered them heavily enough for run off. And what should the soil ph be? I haven’t t been able to find any info in that.

[dilvish]

Fabric pots sitting directly in a catch basin (basically a plate) or on any flat surface will reabsorb any water that pools at the bottom. when I say raise them I mean there needs to be airflow underneath as well as a way for the runoff to escape completely. Even if you have those little gratings underneath, if the fabric touches any part of the runoff it will reabsorb it. Maybe invest in a wet/dry vac to suck up overflow. You should have 10-20% run off when watering and again at those temps not water again for 3-4 days or if the soil feels dry up to the second knuckle of your finger pushed into the topsoil

Additionally your water and or water/nutrient mix needs to be 6.5 PH going in. Forget about the soil PH...just water with properly PH'd plain water every 3rd or 4th watering.

It does look like a nutrient problem and again Pro Mix wouldn't be my first choice. read my first post again...