What casing soil should I use for milky mushroom and how to prepare it?

Casing is a layer of treated soil you spread over the fully colonised substrate to trigger fruiting in milky mushroom. A common casing mix is well rotted farmyard manure with garden soil, or coir pith based mixes, prepared to hold moisture yet stay loose and airy with a near neutral to slightly alkaline pH. The most important step is to pasteurise or sterilise the casing before use, by steaming, hot water treatment or formalin treatment followed by airing, so you do not introduce moulds and pests through the soil. Spread the casing a few centimetres thick over the colonised bags or beds, keep it moist with light misting, and maintain warmth and humidity until pins appear. Poorly treated casing is a common cause of contamination and poor fruiting. Get the exact casing recipe and treatment method that works in your area from your KVK or DMR Solan.