Thank you for your interest in biochar and for taking part in the Sonoma Ecology Center’s 30th Anniversary Victory Garden Project. The bag containing a compost/biochar blend that you received is just a small sample that we hope you will try. You can buy this same blend by the cubic yard and pick it up yourself from West Marin Compost, located near Nicasio in Marin County for $45 per cu yd. Bagged blends from a couple of different makers can be purchased at Harmony Farm Supply & Nursery in Sebastopol.
Here are some additional resources about biochar: