Button mushrooms (Agaricus bisporus), grain spawn, 20 liter

Brown button mushrooms, (Agaricus bisp. var. hortensis, champignon de Paris). Grain spawn only, not a growing set.
This grain spawn is intended for growing brown button mushrooms on a substrate of fermented horse manure. For detailed instructions on preparing the substrate see e.g.
"Pilzanbau in Haus und Garten". This book is available from us but is unfortunately only in German.
Required quantities:
1 liter grain spawn for 50 kg horse manure substrate. The mushrooms will grow faster if you use less substrate.