I gotta agree with @ThePotanist on ‘healthy soil’ & microbial assistance. But i also agree with you @shag, lol I don’t count/depend on the microbial as much as I more count on it as a ‘gradual assist’ that comes as it comes. I go more aggressively/purposeful towards insuring my soil’s health.
If you go to my Circus thread, I just today posted a good number of pics… as you can see, all of the plants are lush, green and healthy.
https://overgrow.com/t/johnnypotseed-s-3-ring-circus-with-autos-photos-sex-reversals-that-is-part-7/
post #1515
from top to bottom, no yellow or dead/dying leaves. The plants weren’t ‘pruned’ to make em pretty for the camera, either! lol
edit… I lied! lol just looked harder at the pics, and did see a very few bottom leaves with some damage , maybe 4-5 out of all those plants. But I think it’s more from lack of light getting down to them than anything else.