leaf tips yellowing in 100% organic grow?

[iBogart]

https://www.nature.com/articles/187621a0

just do some research. I could post hundreds of similar articles

but essentially:

The plant releases exudates into the rhizosphere in response to specific needs of the plants. If those needs change due to foliar feeding, the plant releases different exudates in response to that changing need.

Huh. Learning everyday. Thanks dude.