Mushrooms that grow between the 1st and 2nd break are called tweeners or in between mushrooms. They are very hard mushrooms because they had a lot of water at the end of the breaks but will discolor fast, once picked, because of that water. They are, however, white inside and are therefore extremely suitable to use for slicing. Many farms worldwide are growing tweeners, only to use them for their sliced product. However, if you have a lot of tweeners it can have a negative effect on the quantity of pins in 2nd breaks. You need to control the amount of tweeners that grow out and spread them out nicely over the whole shelf. If some spots have many tweeners together the 2nd break will not be able to develop well, and yield will be lost. On some farms I see harvest managers making some extra yield with tweeners but not realizing enough that that extra yield gets lost in the 2nd breaks, where you normally pick you nicest quality mushrooms.
That doesn’t mean you can’t grow tweeners. Some farms use them to control the quantity of the pins in 2nd breaks. Just by leaving them nicely spread over the beds you can control the amount of 2nd break mushrooms. Clean the beds good after the 1st break, don’t pick for 2 days and on the 3rd, day manage it well controlling the in between break. If you see the 2nd break coming up spontaneously you can leave some more tweeners, if the 2nd break is struggling on some spots, you must open the in between break up and pick some more there. That need to be planned and managed good to get the best benefits out of the total production.
Erik de Groot
Global Agriculture Services