Founded in 2008. The Landscape Juice Network (LJN) is the largest and fastest growing professional landscaping and horticultural association in the United Kingdom.
LJN's professional business forum is unrivalled and open to anyone within within the UK landscape industry
LJN's Business Objectives Group (BOG) is for any Pro serious about building their business.
For the researching visitor there's a wealth of landscaping ideas, garden design ideas, lawn advice tips and advice about garden maintenance.
Replies
Tricky one this as it depends on whats beneath the soil, is there a sublayer of hard impenetrable material that will form a drainage barrier - could be concrete, compacted builders rubble/rubbish etc. Thats the key factor. If there is, that'll need to be broken up / drainage capilaries created first.
If it's normal subsoil underneath, then it's budget. 6" minimum, 12" good. Please don't use normal British Standard 10mm Graded Top Soil as this will be too stoney. Needs to be 2-3mm screened - remember it's screened via slats not a grid.
If the soil texture is ok but just poor in nutrients then adding OM to start increasing soil microbes & goodness would be an easier fix. However if very clay-ey or sandy then yes get rid of 3-6" and replace with good quality topsoil.
But I would definitely decompact the sub-sub soil while the top layer is stripped off as their machines will have tracked over it to create that impenetrable drainage pan that Andrew mentioned.
Depending on the underlying sub soil it maybe worth ensuring a layer of gravel 2-3") under the top soil layer