is it possible that to much perlite/pumice can make the soil to salty for marijuana? peat moss, washed sand, perlite, pumice. Is currently the seed starting soil im useing for my seedlings, and for some reason they do not want to grow they seem to start yellowing and browning slow growth stunted growth within the frist week of growth?? Thanks for the information guys.
No, isn't a salt issue, sounds like your soil mix is too acidic. I would transplant them into another type of commercial potting soil (except any of the Miracle Gro soils), and let them recover. Then start them on a nute program.
Perlite and vermiculite are pretty much sterile and inert, but I remember hearing something about certain brands of vermiculite having nutrients in it that affect its ph. Peat moss, sand and pumice are really not necessary. Stick with some good quality commercial soil supplemented with perlite and vermiculite and you will be good to go. It should hold together enough to make a loose ball, but easily fall apart and crack in half if you jab a finger into it, allowing for aeration and drainage. Or you could just use rockwool cubes...