I am interested in making my own potting soil for a container garden because I read that it's cheaper and much more nutrient-rich to make your own instead of buying the pre-bagged stuff at the garden center that leaches out the nutrients in one season. How do I find these components cheaply? I can't find all of them at the big-box garden centers, and I would think the specialty garden stores would be more expensive. I also don't need a metric ton of these things. This is for a balcony container garden.
coir fiber
perlite
vermiculite
rock phosphate
kelp meal
greensand
