Crushed, Washed, Screened Granite

Heinz Grotzke writes in Biodynamic Greenhouse Management: “The best addition to the soil blend is granite crushed to the size of river sand or somewhat larger. For root growth the particle shape is an important factor. A crushed screened rock has sharp and irregular edges—a physical advantage for both drainage and root formation, especially in the development of secondary roots as they occur on cuttings and young seedlings.” Heinz also emphasizes the value of material with “fresh edges” from the bedrock, for its silica content and its formative influences. We are fortunate to have a major granite quarry just down the road from us, and this manufactured sand is made to our specifications.

Perlite

Perlite is a volcanic glass, popped like popcorn by fire. We use a coarse grade of perlite which is a standard horticultural light aggregate that holds water, maintains dimensional stability, enhances drainage, and mimics the benefits of volcanic soils.

Vermiculite

A mica mineral, expanded by fire that povides capillary shears, enhances texure, supports biota, adds minerals, and carries water.

Bone Char

Bone char is an active charcoal (bio-char) and provides absorbative sites to capture soluable nutrients. It is a good source of devolvable phosphorous.

Mined Gypsum

Mined gypsum provides sulphur and calcium and helps to retain protein. It also helps soil aggregate (flocculate).

Langbenite Rock

Langbenite rock is a soluble mineral salt sometimes called sul-po-mag. It is a NOP-allowed source of sulphur, potassium, and magnesium.