For optimal mushroom growth the casing soil is very important. This is nothing new. However, many mistakes are still made when casing soil is applied to the compost.
– If the casing soil has a fine structure, do not press the layer too firmly; otherwise this will block the pores in the casing soil and restrict evaporation from the compost to the mushroom.
– A coarser casing soil must be compacted more firmly; otherwise too many gaps will occur in the upper layer where there is too little casing soil. This type of casing soil can cope with more intensive levelling particularly at the top to prevent this problem.
– In both cases its vital to closely watch how the casing soil is levelled An even layer of casing soil will give even crop development.
– If casing soil is applied by hand for example on bags work with a light touch to avoid over-compacting.
By John Peeters, C point