No dig gardening is an approach to cultivation favoured by many organic gardeners. The primary reasons for digging the soil are to remove weeds, to loosen and aerate the soil and to incorporate organic matter such as compost or manure. However there is a strong case against digging, which argues that in the long term it can be deleterious to the soil's health. Whilst digging is an effective way of removing perennial weed roots, it can also cause dormant seeds to come to the surface and germinate. Digging can also damage soil structure and cause problems like compaction, can disturb and damage balances amongst soil life and by exposure to the air, tends to burn up nutrients which then need to be replenished.
No dig methods rely on 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 2 or 3 inches deep, which is then incorporated by the actions of worms pulling it downwards. 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 pestss and disease, possibly due to a more balanced soil population being allowed to build up in this comparitively undisturbed environment, and by encouraging the build up of beneficial rather than harmful soil fungi. Moisture is also retained more efficiently under mulch than on the surface of bare earth.
Converting to a no dig system is however a long term process, and is reliant upon having plentiful organic matter to provide mulch material. It is also necessary to thoroughly 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 opened out newspaper (overlapped to provide thorough cover) before adding the compost mulch.
No dig is not a technique that is appropriate in all situations, but organic gardeners and farmers should at least consider minimising soil disturbing practices if they are to reverse soil damage and erosion.
No dig gardening systems are strongly recommended by Dr Shewell Cooper of the Good Gardeners Association.
