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 half gallon bag will fill about 9 of the four inch black pots to the top indention.