10 cups- Soil Mix for a balance of Inorganic/Organic Bonsai Soil. 20% - 1/4" - 1/32" Natural Cascade Mountain Volcanic Lava rock. Pleasing mix of red, grey, black and white. 25% - 3/8" - 1/32" Natural Cascade Mountain Volcanic Pumice. Pumice has many tiny gaps or air pockets that allow roots access to oxygen, nutrients and water. 15% - Turface MVP. Turface MVP is a high fired Calcined Clay. Particle size is 3/16 and under, has few fines, but has not been screened. 20% - PRO-MIX BX MYCORRHIZAE is a general purpose peat based professional growing media, unscreened. 20% - Fir Bark - 1/2" minus, unscreened. Approx. 10 cups volume. All natural, relatively light weight and porous. Our potting mix is hand packed and bagged with a reusable tie for easy storage after you have used part of the bag. If your potting mix dries before using, moisten it to keep dust from forming. Dust from any rock or potting soil product should not be inhaled and can be irritating for people with sensitive lungs. We are a commercial Wholesale / Retail Plant Nursery with over 15 years mixing specialty potting mixes. Check out our other listings of custom potting mixes to select the perfect mix for your bonsai or specialty plants. Scenic Hill Farm is a licensed Oregon nursery -- license # L0170090NG