Can't figure this out?

[desertdan]

There are leaves turning yellow on several plants. Only large older leaves but change color very rapid. Starts at bottom and moves up.Thought it was root aphid return at first. Treated for ra for about 10 days. There are no visible root aphids at this time and I am convinced they are not return. One of the plants with yellow is in preflower others are in bloom. I added a cal/mag supplement and no change. ph is 6.5 and 7.0
Base for soil mix is promix sunshine #4. First 2 pics are of Acapulco gold and then wild thai bud where plant has same problem.

[OldManGrower]

I wish I could help. I had the same issues with 00Kush plants. I was never able to resolve the problem and had to harvest early. Maybe it is the strain? The 00Kush was still quite potent but I had the same issue repeatedly.

[desertdan]

several strains same symptoms

[OldManGrower]

Plant virus?

[DW2]

Howdy desertdan, I'm not a soil or outdoor grower, but it looks like something has been eating on some of the leaves, could it be small pests? Also, what agricultural endeavors (if any) are up wind of You? Maybe it could be from some sore of spray drifting on to Your plants?
I do hope that You can figure this out and save Your crop!

[desertdan]

No bugs cause this. National park is my biggest neighbor.

[DeadlyFruit]

One of my plants really suddenly (over a couple days) had some leaves go yellow and start to die. I believe in my case they had exhausted the nutrients in the soil and were slightly under watered. Once I started adding nutes and watering more often the yellowing slowed right down. I think for me it is just not being used to having such giant plants using more water and nutes than I am used to.

[desertdan]

Thank you DeadlyFruit . Your comment put a light on in my head and I figured it out. GWE rocks!

[DeadlyFruit]

Pleasure! 🙂

[desertdan]

After some research and asking around I think I have found the problem. DeadlyFruit is correct. The rock Phosphorous I am using is probably not fast enough release for such large plants with big colas. I will be adding water soluble P in the morning. Thanks to all.

[JK2020]

Looks like Septoria (yellow leaf). It's a mold/spore (which can live/remain in the soil even over the winter). Typically starts at the bottom and works it's way up. Remove all the yellowing and decaying leaves and lower larf to let the plant breathe and ensure there is good air circulation. Keep the ground under the plant clean and clear too.

[desertdan]

not Septoria. Common problem is usually what it is.

[Spog]

After ida my gelato did same some lime and 2 feedings and cal mag in between and I think it's stopping I have to check the calendar but I think it's time for some budswel

[desertdan]

yeah I did the cal/mag yesterday. Thanks

[silasjack]

Usually when lower leaves turn yellow and fall off easily its low nitrogen. Check with gwe plant problems for sure though.

[Spog]

So I think I have my gelato in check seems to be getting better

[OldManGrower]

Glad you arrived at a solution DD.