Wet compost and wet casing, a tricky combination

Jan 11, 2022

It looks like we are not going to have any winter this season in Europe. On the contrary. It is very wet and humidity is very high.
This has its reflection on compost and casing.
If raw materials for compost are stored outside or under just a roof, they are evaporating less water and in the same time some materials get wet by the rain.


If the materials are not checked regularly (meaning every batch) before they are going into the system the compost manager cannot interact on this. If the composting is not adjusted this will result in a few percentage points more moisture. By itself no problem at all If the grower knows about it.
It gets more difficult though if also the casing is getting wetter.
As a normal result of the rain the peat gets wetter during storage.
And many casing yards have a big stock laying outside. Because of expected frost during winter they tend to build up stock. A normal procedure every year around this time.
Getting a casing wetter during production is fairly easy. But getting it drier is more difficult.
Mixing in dry white peat is normally the answer but this generally results in a finer mixture which most growers do not want.
Result for many growers is that first flushes have problems growing out. The numbers are too low and second flushes have a problem with quality. They mature too fast and picking time is too short.

So what can be done?
If a grower knows the compost is already a bit wetter he can adjust the watering schedule immediately. Less or no water during filling and a change in schedule of watering on the casing during case run.
Also the filling can be changed technically. A wetter casing can be more lumpy or even slightly anaerobic. Especially if casing is stored a while before filling.
It is possible to run the caccing spinner a bit faster to open up the layer of casing. More caccing, by putting the spinner deeper, is not always necessary. Caccing more has a fairly big impact on the growing.
At the same moment the levelling spinner should run slower to create a sort of “digging” effect. This is done to keep the surface of the casing open.
After filling and casing the total amount of water can be around 20 to 25 litres per m2. Depending on the amount of mycelium that is desired.
In outgrow make sure enough fresh air is taken in. especially on day 7 of the break this is essential. Rooms which have a hard time in growing out have a very low demand for fresh air because of lack of activity of compost. Make the minimum fresh air setpoint is at least 15%.