Yea I'm not too big into sand. Mushroom compost is nice, not too much for seedlings though as it is very rich and can burn as mentioned earlier. Fox Farm Ocean Forrest is good, I personally like Happy Frog organic soil because it is a little better deal and hey...its from Mendocino County so its gotta be pretty good. Hah. Adding perlite and vermiculite is straight. I like to also add earthworm castings as a great nitrogen source (you can't put too much of this stuff!:thumbsup and Fox Farm Peace of Mind Fruit & Flower and Bat Guano. Good luck.