When making potting soil mix for plants down here in Florida where there is nothing but sand which can compact to a very stringent degree: I like to use both vermiculite and perlite along with some potting soil & sand. I mix them all together. Generally, anything I'm putting in pots is only to grow them on until they can go in the garden. I find the perlite lightens the mixture considerably & the vermiculite holds more water so it doesn't run through the sand & perlite. With the extreme heat we have here I need something to hold the moisture in the soil & the vermiculite does that well.
