Choosing the right grain for mushroom cultivation comes down to three things: colonisation speed, nutrient density and contamination risk. Rye is the most popular — it colonises fast and mycelium loves it — but that same nutrient richness makes it more vulnerable to competing moulds. Millet colonises almost as quickly, is harder to over-hydrate, and is widely considered the most forgiving grain for beginners. Popcorn sits somewhere in between: cheap, readily available and reasonably … read more