For the first time since I've had a plot, a local farmer has kindly dumped a mountain of horse manure for everyone. It looks excellent consistency...not too fresh but certainly not like the bagged stuff from garden centres. Parts of my plot has a high % of clay in the soil and this looks like a good opportunity to really improve matters. But how much to use? Some plotters have a thin layer others have put down an 8-10" covering. Can you over do it? Also, does it need digging in or can you leave it to break down and just use the beds next season. Also, best to cover it or leave open?
Many thanks for all the guidance.