How much gypsum in gritty mix
I am about to plant a (3 gallon) Fairchild mango tree in a 25 gallon container using Al's gritty mix as the medium. I have the Turface, Granite grit, Pine bark and the Gypsum ready to be mixed. Could someone please tell me exactly how much gypsum to add to 25 gallons of gritty mix? This is my first time trying the gritty mix and I want be very exact on this part since I know that too much gypsum could burn the roots and too little would not lower the pH enough.
One other question: If I don't use the 9-3-6 foliage pro liquid fertilizer, is there another good liquid fertilizer that someone would recommend using in this mix that contains all the minors as well? And could a control release fertilizer(CRF)be used with Al's gritty mix?
After reading so many links and threads on this subject,
I would like to thank everyone, especially Al, for helping me up to this point in this project.