No Dig Gardening – A No Nonsense Guide

No dig gardening is one of the keystones of contemporary, organic gardening practice. If you want to create a healthy and productive garden then you may imagine that plenty of backbreaking digging will go into creating your perfect growing areas. On the contrary – the best organic polytunnel gardens do not require much digging at all. Read on to learn more about the principles, benefits and practices of no dig gardening.

What is No Dig Gardening?

No dig gardening is simply a method of creating and maintaining growing areas in a garden without extensive digging of the plots. In no dig gardening, growing areas are created by layering organic material on top of the existing soil, and maintained by means of sheet mulching. The soil beneath is left as undisturbed as possible, allowing the natural soil ecosystem to thrive.

The Benefits of No Dig Gardening

There are a number of reasons why no dig gardening is a good idea for an organic polytunnel garden. Some of the benefits of this practice include:

• The soil ecosystem is able to thrive. Fungal and bacterial networks remain unbroken. Other micro-organisms and soil fauna like earth worms are left to do their job.
• The soil is better able to retain moisture for water-wise gardening, and less likely to suffer nutrient depletion due to run-off and erosion.
• Heavy clay soils, sandy soils and other potentially troublesome soil types are naturally improved over time by this gardening system, as organic matter is added. (Lessening problems such as compaction and generally improving soil texture and fertility.)
• The natural cycle of growth, death, decay and regrowth is used to complete the nutrient cycle and create a closed loop, so an organic garden can be maintained effectively and even improved over time and waste is kept to a minimum.
• No dig gardening saves a gardener a lot of backbreaking work, and makes it easier to maintain an organic gardening system from a human perspective.
• There is evidence to suggest that no dig gardening can increase yield when compared to more traditional gardening practice.

The Basic Practices of No Dig Gardening

An understanding and implementation of no dig gardening practices begins with at least a basic understanding of the soil ecosystem. The soil food web is a connected network of bacteria, fungi and other organisms that allow for the effective transfer of nutrients and water beneath the soil. The soil’s biota allow organic matter to be broken down over time, and for the nutrients this matter contains to be returned to the subsoil for uptake by growing plants. No dig gardening simply allows natural processes to take place on and beneath the soil surface, as free as possible from human intervention.

The basic practices of no dig gardening are incredibly simple. Terms that it is helpful to understand within a no dig gardening context are:

• Lasagna garden beds.
• Hugelkultur.
• Straw bale gardening.
• Mulching.

Lasagna Garden Beds

When first creating no dig growing areas, there are several potential methods that you could use in your polytunnel. The first and simplest of these to familiarise yourself with is the ‘lasagna’ method. In this method, new garden beds are built up on top of the soil using layers of organic and waste materials. These beds may or may not be surrounded by bed edging or various kinds to create raised beds.

Often, you will begin by laying cardboard sheets on top of the existing soil or turf. You will then add ‘brown’ and ‘green’ materials in layers to create beds of the correct depth (in exactly the same way that you would build up a compost heap), and top with a layer of compost into which you can place plants or sow seeds. Over time, the materials of your lasagna bed will break down and the bed will naturally become part of the soil ecosystem.

Hugelkultur

The concept of hugelkultur is another common practice in no dig gardens. In hugelkultur, the principles are more or less the same as in the creation of ‘lasagna beds’. However, in hugelkultur (‘mound culture’) you will, instead of creating flat raised beds, create raised mounds of organic matter on top of the soil.

Hugelkultur mounds are built up by piling partially rotted wood logs, branches and sticks below layers of carbon-rich, brown materials and nitrogen-rich, green materials. These are compacted a little and, again, topped with a thin layer of compost. As with ‘lasagna beds’, in hugelkultur, the mounds will break down over time, releasing nutrients. They will naturally become part of the soil ecosystem without the need to dig the organic matter into the surrounding soil.

Straw Bale Gardening

Another way to create new growing areas in your no dig polytunnel is with straw bales. Straw bales are soaked in a nitrogen-rich liquid feed which will facilitate their decomposition. These straw bales will be topped with planting pockets of compost into which plants or seeds can be placed.

As they break down, the straw bales will lose their structure and generate heat, while also releasing nutrients for plants and into the soil ecosystem beneath. This is another way to create fertile and productive growing areas without disturbed the soil food web.

Mulching

No dig gardening is not just about creating new growing areas. It is important to remember to allow for continued and sustainable fertility over time in your polytunnel garden. Since, as gardeners, we are taking something (the food we grow) from the soil, it is important that we replace what we take and close the natural cycle. Mulching is the main method by which no dig gardeners replace the nutrients that were taken by their growing crops.

Mulching is the practice of laying organic matter on the soil surface. While in many gardens, organic matter is dug into the soil in growing areas, this can actually do more harm than good. When we lay mulches on top of the soil, we are protecting that soil and the life that helps its systems to function. When functioning as it should, the soil ecosystem is fully capable of incorporating that material without human help.

Different Sheet Mulches for No Dig Gardening

After your no dig growing areas have been used to grow crops, it is important to mulch in order to replace nutrients that have been lost. Mulching will also help to protect the soil ecosystem by reducing water loss and preventing erosion. Mulching is not a one-off practice, but one which you will continue over time. As mulches break down, they are continually replaced or replenished.

Which mulch or mulches you choose to use will depend on the main purposes, your situation, and the quality and features of your existing soil. Common mulches include:

Compost

Home-made compost, either completely or partially composted, is one of the best mulches for a UK no dig garden. A well-made compost is balanced in nutrients, rich and friable. It is also something that all polytunnel gardeners can have access to.

Autumn leaves or leaf mould

Autumn leaves, when partially or fully decomposed, also make an ideal soil fertiliser. By adding autumn leaves around your growing plants, you can mimic the rich and fertile environment of a forest floor.

Manures

Another good source of nutrients for your garden beds are animal manures. However, it is important to note that most manures must be well-rotted before they are used as a mulch around your plants. Manure from chickens or other poultry, from pets such as rabbits, hamsters or gerbils, or from farm animals can all be left to rot and then spread as sheet mulches around your crops.

Straw or Bracken

To protect the soil surface and add humus, straw and bracken are both ideal mulches to use. It is important to consider which by-products may be available where you live, and to use whatever you can easily get your hands on.

Nitrogen-rich grass clippings or other green leaves.

Nitrogen-rich grass clippings and other green leaves, weeds etc. are used as a mulch.  These provide a boost to leafy greens.

Comfrey

Comfrey is rich in potassium and so is ideal for use as a mulch around tomatoes and other fruiting crops. Layered thickly, comfrey leaves will break down and add fertility to the soil.

Seaweed

If you feel that your soil is low in micro-nutrients, a seaweed mulch could be the answer. Rich in a range of nutrients and micro-nutrients, seaweed could also be readily available if you live near a coast.

Common Sense Approach to No Dig Gardening

While the aim in a no dig garden is always to disturb the soil ecosystem as little as possible, it is important to remember that there will still be occasions when you will wish to enhance your garden through digging down. While you will not need to dig in order to incorporate organic matter, you may still have a number of practical reasons to disturb the soil a little. For example, you may:

• Dig a garden pond to attract beneficial wildlife to your garden.
• Create swales, irrigation ditches or other water management features in your garden.
• Create a pit for charcoal production, or a new biochar bed. (This can be a fix for areas with soil of very low existing fertility, or with very poor water retention.)

The key to successful no dig gardening is understanding that there is rarely a ‘one size fits all’ solution. While it is important to be aware of the soil ecosystem and take measures to protect it, you may still take up a spade from time to time. Take a common sense approach – take into account your own individual circumstances and situation – and you are far more likely to see positive results.

How have you got on with no dig gardening? Share your own experiences in the comments below.