Due to the current warm weather there are more problems with chestnut mushrooms. Chestnut mushrooms prefer lower temperatures which are difficult to achieve at the moment. The first flushes are on the light side but the second flush in particular lags behind on quality and kilograms. Often copious water is sprayed after the first flush and as a result the casing layer doesn’t dry out enough. Fruit body formation is seen, but further development stagnates.
At the moment it’s better to spray no more than 4 to 6 litres of water per square metre after the first flush and after spraying ventilate enough for 12 to 14 hours. Increase circulation until you see that the pinheads are drying. Then reduce circulation step by step and allow the CO2 content to rise to approximately 1200 ppm. This method does mean the second flush has to be sprayed otherwise the flush will be too dry and the colour of the mushrooms will stay pale. Despite these measures chestnut mushrooms remain difficult to grow during this season and require constant attention and professional expertise. Each growing room must be carefully inspected and each room requires a different approach.
Henk van Gerwen, AdVisie ‘The mushroom cultivation advisors’