On Saturday, 6 February 2016 03:26:26 UTC, wrote:

More like 'typical', I'd have thought. You could try covering a couple of
square metres with carpet and black sheeting for 24 hours when the soil is
damp. If, when you take it off, you have a couple of hundred leatherjackets,
that would be bad. If you have ten, that's normal.

I did around a square *foot* and got this: (high res for zooming)

http://www.newtonnet.co.uk/permanent/grubs1.jpg

Of particular note were around 50 of these:

http://www.newtonnet.co.uk/permanent/grubs2.jpg

Which I am guessing are slightly more immature versions of these, of which there were a good 10-12?

http://www.newtonnet.co.uk/permanent/grubs3.jpg

Mathew