Middle leaves yellowing

[dreamgreen]

These girls have been through a lot. Latest issue is the middle leaves are yellowing and dying off, slowly spreading to the upper leaves. I’ve made sure ph is 6.5. Not sure what to try next.

 

[az2000]

What is the soil (sand?). What are you feeding?

 

[dreamgreen]

Soil is topsoil w/rice hulls, the half-inch layer of sand on top was to get rid of fungus gnats. I use general organics “grow” in distilled water, plus hydro guard, pH’d to 6.5. Also added zinc a couple weeks ago but no change.

 

[az2000]

When was the fungus gnat problem? How bad was it? Maybe they damaged the roots? I've never grown in top-soil. It seems like that might be heavy/dense, slow-drying. With it being covered in sand, can't see what it looks like.

 

[dreamgreen]

It was pretty bad, they finally cleared up about a week ago. Had root rot before that, hence the switch to fabric pots and a true wet/dry watering cycle. Hydroguard too. There were definitely some twisted/stunted branches from the root rot, which i cut off, but this yellowing issue is fairly new.