By Helensmith
United Kingdom 
Digging plot found big patch of soil with white powdery stuff what could that be
24 Feb, 2018
Answers
I thought same as you Sbg...fungus.
25 Feb, 2018
without a photo it is difficult to say. But it is possibly fungal hyphae. have you burnt any material on the surface and forgotten about it ? it could be ash.
24 Feb, 2018