when you need lots of potting soil...
I grow various things like plumeria and fruit trees. Since I have limited room for in-ground planting, large planters are of interest.... I'm beginning to consider larger pots (maybe > 15 gallon? for some reason pots are not labeled in terms of the volume they hold.)
In all my smaller pots I've made the gritty mix. In a perfect world I suppose I would use this in very large pots also, but I simply cannot manufacture it in those quantities and it would also be quite expensive. In fact, even something like MG cactus mix is an expensive option considering it is only sold around here in tiny bags at $4 a pop.
What do you guys use when you need to fill a huge pot? I'm guessing it might be more cost efficient to buy a couple of materials in bulk and assemble my own but I'm curious what you guys do.