White mold in polytunnel

[Katycue]

Hello
Can anyone shed any light on what this substance is on the surface of my soil in the polytunnel. It is appearing just on the edge of the beds, it is quiet hard and lifts out easily but I am worried it will ruin my soil.

Many thanks in advance

[Plot70]

It is most likely a fungus and will not harm the soil.
If it were soft I would say slime mold.
Whatever kind of fungus it is the result will be a fertile liquid like bottled plant food. So it is at least harmless or most likely good.