Faced by falling prices and an often huge volume on offer, growers are being forced to concentrate on offering better quality and more grades. This isn’t normally a problem in the first flush, but can be slightly more of a challenge in the second flush. To be able to pick continually over several days the flush must also spread over the same amount of time. And this is the root of the problem. Second flushes often tend to develop in a single massive spurt so the actual harvesting period is very short and high volumes have to be picked on day 1. On the second day of picking the flush often develops too quickly and looses quality.
Growing an intermediate flush between the first and second flushes can be the solution. On the final harvesting day of the first flush 05 kilo per square metre should be left evenly distributed throughout the growing room. Immediately after harvesting the grower can water to raise the moisture content in the casing soil No more water is given subsequently but the growing room is quickly and effectively dried which encourages the catch crop of mushrooms to develop. This intermediate flush is then harvested in at least 2 days at a size of 50 to 60 millimetres. Spreading picking and allowing the mushrooms in this flush to grow to this size will result in a better spread in the second flush – which will be last longer and give better quality mushrooms. The pickers must be instructed beforehand about how to deal with this technique.
Henk van Gerwen, AdVisie 'The mushroom cultivation advisors’