Use fresh, dry, golden paddy straw stored under cover since harvest. Straw that got wet in the rain or has turned grey carries mould spores and is not worth the spawn. DMR prefers hand-threshed paddy: the stems stay long and whole, so bundles hold together. Machine-threshed straw is crushed and short and makes loose beds that dry out.
Make bundles of 0.75 to 1.0 kg, about 80 to 95 cm long and 12 to 16 cm thick, tied at both ends. A DMR conventional bed uses 30 to 40 kg of dry straw. TNAU's smaller bed uses 10 to 15 kg. Start small: a first bed of 10 to 15 kg teaches the same lessons.