Activity in third flushes is often below par. Sometimes the appearance of a third flush is less spontaneous. For growers with a higher filling weight (95 kg/m2) there are fewer problems.
It is important not to spray too much water on the casing soil after the second flush. If the casing soil is too wet, there will be fewer pinheads and they will often appear later. Just moistening the casing soil using 2 to 4 litres of water per square metre is normally sufficient. It's best to spray this amount twice at a 1-hour interval. Heating the compost for 12 hours to 21 degrees Celsius at an air temperature of 23 degrees will have a positive impact on compost activity. RH at that time can drop down to 76 – 80 % with no problems.
After this 12-hour period reduce air temperature to 19 degrees Celsius with RH of 83 % and keep these values until the end of the flush. When heating the compost ventilate slightly more than usual before dropping back to the standard value. Keeping activity alive will encourage a more spontaneous third flush and mushroom colour is often better.
Jos Hilkens, AdVisie ‘The mushroom cultivation advisors’