This is David's own special germination mix, designed by David to optimally germinate garden seeds. Finely screened growing medium creates optimum germination conditions. Excellent for small-seeded crops and seeds that prefer fewer nutrients for germination. Screened to 1/4 inches. We use this to start our plants here at David's Garden Seeds® in our greenhouse. It works great and is light weight. Use in any type of pot for seed germination. The one gallon bag will fill about 18 of the four inch black pots to the top indention.