Alison Wessely
The Royal Horticultural Society reports that double digging makes a significant difference to crop yield and growth and health of plants where soils are truly compacted and the ‘no dig’ or single digging method has proved ineffective. https://www.rhs.org.uk/soil-composts-mulches/double-digging.
Personally I often employ this method in gardens where borders have not been cultivated with organic compost or mulch for a number of years. The joy of double digging lies in transforming compacted, low quality soil into a rich, well-aerated environment for plant growth.
This process enables you to extract deep rooted perennial weeds as well such as Bindweed (Convolvulus). The fleshy tip of the rhizome root of this invasive weed can normally be teased out at a depth of 30-40cm.
Digging in organic matter helps the soil hold air and water. When carried out properly, double digging using organic matter can enhance the soil environment by supporting the microbes and mycorrhizal threads that feed root systems by providing the air and moisture they need.
The double digging technique I use can be arduous, so take it easy if you haven’t dug like this before! Stretching your back and quadriceps can help beforehand and during if you have a lot of ground to dig, and have a hot bath with Epsom salts later on to relieve any muscle stiffness. Top tip!
- Dig a trench approximately 1-2 times the depth of your spade by the width of the spade along the length of the bed you are working on.
- This soil is then removed, placed aside and kept for later use.
- Fill this trench with good quality well rotted manure or compost.
- By stepping back away from this first strip, repeat the process from 1. with a second trench alongside the first but this time, place the soil that is removed here over the compost in the initial trench creating a sort of compost sandwich.
- Repeat this until you reach the end of your border. The height of the soil will have raised a lot now due to the de-compaction but this will settle down in a few days. When the task is completed, dropping your fork from a height into the freshly dug bed and watching it disappear into the dark crumbly friable and fertile earth is in my experience, pleasurable to say the least!
