Why dig? Why turn over tonnes of topsoil year after year. We know permanent soil has properties that annual crops need and which sustains bio diversity. Why disturb and destroy the goodness that nature provides?
Salad, herbs, onions, garlic, brassica, peas, beans, and ornamentals are examples of plants that can be cultivated without digging. One simple method to achieve surface drainage and root development with minimal soil disturbance is to cultivate narrow drainage channels.
Minimal cultivations can be disappointing when applied to crops you want to grow from seed in the same growing season. This is because broadcasting seed onto permanent soil suffers from two issues:
- A fine tilth is required for even germination.
- Seedlings / young plants need surface drainage for root development.
Fine, moist soil needs to surround seed sown at the correct depth if we expect our crops to germinate and emerge evenly.
Seedlings sat in saturated soil produce stunted roots; if they survive at all. Stunted roots equal a stunted plant.
The narrow drainage channel cultivated under the centre of a band of plants is a compromise between permanent soil and its cultivated cousin. There is enough loose soil on the surface to make a seed bed with a fine tilth. The channels contain loose soil that encourages surface drainage. Overall the ground is still firm, self-structured soil. In a field situation you could walk or drive over it without making marks.
Young plants propagated above a narrow drainage channel develop in a healthy manner. Extensive root systems grow deep into the soil profile. The roots of growing crops can break into worm burrows or channels left by a previous crop that has decayed. Here they find moist soil with nutrient that is released slowly from organic material.
Wildlife friendly gardening begins beneath us. Turning the top soil over reduces worm populations and opportunity for biodiversity in the leaf litter. Composting worms, beetles, spiders, earwigs, woodlice and many other mini beasts use the detritus that sits on the surface of the ground for habitat. Digging in the previous crop looks tidy but the creatures that live in leaf litter are beneficial. They belong in many food chains; often being predators of crop pests such as aphids, caterpillars and slugs themselves.
Climate change has been encouraged by agricultural practises over many years. Millions of hectares of cultivated soil around the world have eroded. The soil fertility has been washed away and the soil’s bank of carbon has been released into the atmosphere as carbon dioxide. Narrow drainage channels are a solution because the soil is mostly undisturbed when crops are grown using this method of cultivation. Watch the video below to see how it works.
It is preferable to use trees, shrubs and perennials for food, fuel and ornamental production. If we have to cultivate the ground layer to satisfy our appetite for a wide range of foodstuffs then a no dig system is win, win and win. The gardener saves effort, sustains wildlife and contributes to slowing climate change.
Andrew Astle has grown food and ornamental crops for thirty years. In recent years he has needed to find a method of gardening that requires less effort. He was diagnosed with cancer in 2005. Treatment left him weak and the muscle was removed from his neck and shoulder. He joined the permaculture association recently; after reading “Permaculture a Designers’ Manual,” he realised that his no-dig gardening method benefits wildlife and the wider environment.
His book “TINE” How to Garden Without Digging is available from his website at: www.soilisalive.com