HELP! Please help me diagnose this problem. Rusted, brown, curling leaves.

[BigChong]

Hi everyone,

I'm hoping you guys can help me with this, I can't figure out what's causing this rusting and curling of the leaves on my plant. It's my first grow, just over week one of flower.

Everything was going great until about two days ago when I noticed some of the leaves were rusty, brown/beige and shriveled around the edges. Some of the leaves seem to be dying. This seemingly happened overnight. I have some (assumed) fungus gnats in the tent, which could be one possible cause. I also suspected potassium deficiency, I've been adding under 1ml of calmag to my water along with the nutrients. Because it's a soil grow I realised I don't need to do this. Could this be causing a potassium "lockout"?

I checked out the GWE diagnostic chart and the closest match is a potassium deficiency.

Here's some pics of the problem along with pics of the new growth to compare.

* TS600 light
* Tatanka Pure CBD
* Soil/perlite
* GH Trio nutrients - (currently 2ml Micro, 1ml Gro, 2ml Bloom)
* Watering approximately every three days, or when the pot feels light @ 6.5-7ph. Intermittent plain pH'd watering.
* 15L Air pot

Thanks!

 

[OlderNOTwiser]

https://www.growweedeasy.com/5-surprising-signs-overwatering-cannabis Bullet point #1 looks like this.

 

[Rwise]

I cant open the pics, but it sounds like a PH issue, whats the soil/medium PH, whats the run off PH?

 

[dilvish]

Plants look quite dark green. If your PH is off then it could be potassium deficiency or maybe nitrogen toxicity. Watering every 3 days is fine as long as they need it. Soil takes longer to dry out so if your temps are too low you may be overwatering too. Try cutting back on the watering. go every 4 days and make sure the air pots aren't left sitting in runoff water.

 

[Brianm]

Hey Dilvish, I have kind of same issue but yellowing fan leaves in flowering stage of a black widow. I’m using bush-doc’s coco loco soil in air pots, water every 3 day(soil dry beyond 1st knuckle), using Dyna-grow & bloom, with good LED lights, using filtered tap water. I had this happen with the mother plant of these and a gorilla glue auto as well. Could this be a Cal-Meg issue? Can you give me some insight to issue.