No-dig methods allow nature to carry out cultivation operations. Organic matter such as well rotted manure, compost, leaf mold, spent mushroom compost, old straw, etc., is added directly to the soil surface as a mulch at least 5-15 centimeters (2–6 in) deep, which is then incorporated by the actions of worms, insects and microbes. Worms and other soil life also assist in building up the soil's structure, their tunnels providing aeration and drainage, and their excretions bind together soil crumbs. No-dig systems are said to be freer of pests and disease, possibly due to a more balanced soil population being allowed to build up in this undisturbed environment. Moisture is also retained more efficiently under mulch than on the surface of bare earth, allowing slower percolation and less leaching of nutrients.
A no-dig system is easier than digging. It is a long term process, and is reliant upon having plentiful organic matter to provide mulch material. It is also helpful to remove any perennial weed roots from the area beforehand, although their hold can be weakened by applying a light-excluding surface layer such as large sheets of cardboard or several thicknesses of spread out newspaper before adding the compost mulch. This system can be used in Polytunnels as well as outdoors.
For those of us lucky to live in the South West, a visit to Charles Dowding to take part in one of his courses, or for those further afield his web site has details of his couses and offers a selection of his excellent books on the subject, and you can sign up for his regular blog by visiting www.charlesdowding.co.uk