Good read here, thanks all. I make my own premix for indoor containers and recently switched from perlite to pumice, which I like better. Can't say exactly why so far, just a feeling! Maybe the sharp rocks look more root friendly to me, don't know for sure yet. I'm hip about the superior holding of cations and all, but I'm an organic grower for so many years I confess I don't know much more about that stuff.
Over the years I've gradually increased my amounts of non organics like sand, gravel, kitty litter (another nice holder of them cations) and the usual perlite and vermiculite, which I've used less of, and now quit.
Other growers pointed out to me that with my relatively small container/big plant grows and organic teas, I'm almost doing hydro in containers. With lots of non organics in the mix, I can let a plant stand right in a tray of water an nutrients for hours without worrying about oxygen debt to the roots. Also, a plant can be left in a container for longer without worrying about the collapse of the non nutritive organics in the mix when there isn't much, or any. A plant left in a container 'till it gets a touch rootbound, but is still well fed and watered, will pump out the hugest flowers it's genes can manage.
Over the years I've gradually increased my amounts of non organics like sand, gravel, kitty litter (another nice holder of them cations) and the usual perlite and vermiculite, which I've used less of, and now quit.
Other growers pointed out to me that with my relatively small container/big plant grows and organic teas, I'm almost doing hydro in containers. With lots of non organics in the mix, I can let a plant stand right in a tray of water an nutrients for hours without worrying about oxygen debt to the roots. Also, a plant can be left in a container for longer without worrying about the collapse of the non nutritive organics in the mix when there isn't much, or any. A plant left in a container 'till it gets a touch rootbound, but is still well fed and watered, will pump out the hugest flowers it's genes can manage.