well the stones come up to the surface due to natural earth vibrations. a bit like shaking the crumble mix to get the larger bits of fat up to the surface.

When we dig the soil we increase the large air spaces. as time passes the rain helps wash the small soil particles into the spaces so the soil settles. Also evry time you take a weed/plant out as small amount of soil remains on the roots you throw away.

Louise why are you removing the small stones? They help to create air pockets so that the plants can breath - yes they do need air! I know it can look unsightly if there are a lot of stones on the surface but if you mulch you will not see them.As to the soil sinking are you adding a mulch every year? If not and you are removing all th ston it will most certainly 'sink'

Thank you both.
Moon grower, i 'wasn't' mulching in this garden until a year ago but i do now, the stones i'll leave there now, there are certainly plenty - for every 6 removed another 6 appear !
Living on a windy, sunbaked hillside adds to the crumble mixture effect too, i guess.

Good luck Louise... after 20 years in this garden we still find broken glass where a previous owner treated part of it as a midden

Just looked up 'midden' ;-)

I think this lot is due to the two previous owners never having worked this land (in 30 years) so it's like a 'new garden plot'.
If i'd known it when i moved in, i'd have got a mini digger and tore the lot up and started from scratch.
Hey ho !

plant roots are used to dealing with stones so its only for asthetics and as youve mulched it its all good.