Immerse the bundles in clean water in a cemented tank for 12 to 18 hours. DMR describes soaking in plain water or a weak lime solution; use plain clean water unless a specialist advises otherwise. Muddy pond water brings bacteria and insects into the bed.
Lift the bundles out and stand them on a slope until water stops dripping. DMR's key practice list asks for 60 to 65 percent moisture in the substrate. Test by hand: squeeze a fistful hard. A few drops at most should appear and your palm should feel damp, not wet. Spawn as soon as the straw has settled at about 35 °C, not before.