An appropriate title for a blog written on Easter Monday.

Normally the 7th day is a day of rest. Good for people after a week of working but not always good if mushrooms take a rest. Read: they stop growing. This can happen during the fructification and if the reaction of the grower is too slow, the flush grows out to be too small.

Fructification is split into two sections. 4 to 5 days for making the mushrooms or forming the primordia. The second part is roughly from day 5 till the start of the first flush. During the first part RH, ambient temperature and CO2 are the main parameters to control the number of primordia. Compost temperature is for me not that important at that time. After day 5 the RH is lowered to let the primordia grow out to be mushrooms. The CO2 is dropped slowly and we also start dropping the temperature to reach 17.5° C ambient temperature at the start of the flush (my favourite temperature to work with).

On day 7 one can see mushrooms developing in the size of 2 to 5 millimetres. And then this phenomenon can occur. You look during your morning check and everything looks good. The next day, nothing has happened. General reaction is waiting. But if you look carefully, in most of the cases the room is not taking enough fresh air. CO2 is okay, RH is okay, air temperature is okay and the compost temperature is declining. If the minimum fresh air setting is too low, the room can have a lack of oxygen and mushrooms just stop developing. Simplest thing to do is to drop the CO2 setting to 800 ppm for a couple of hours. To avoid this however and the best way to handle this, is to make sure that the minimum fresh air setting is around 25%. Then the climate unit will always use enough fresh air and mushrooms keep growing. By the way, this happens mostly with strains which tend to give bigger mushrooms. Because they already tend to give fewer mushrooms.