In attempts to reduce picking expenses many growers have switched to the heaviest possible casing soil in recent years. This means fewer pieces on the beds and therefore an easier harvest. At this time of year however we are faced with very changeable temperatures and RH values and development is not always straightforward Heavier casing soil results in more difficult evaporation and exchange from the compost is hampered. This means you often see that the final kilo just fails to develop properly which can mean the loss of an entire picking day. One option is not to compact the casing soil too firmly. This leaves an open rougher surface Slightly more cac-ing with compost also results in a more open casing soil structure but with the increased risk of the flush developing earlier Plus the compost dehydrates more quickly on the surface which can lead to excessive drying if it freezes at night. You can also decide to temporarily switch to a different casing soil composition in consultation with your supplier They carry a range of various types that have a high moisture content but a coarser structure Simply changing can be enough to tide you over this awkward period When the winter comes and the air becomes drier just revert to the old type of casing soil.
Henk van Gerwen, AdVisie ‘The mushroom cultivation advisors’