Digging your garden

When to dig

Digging the soil is essential for good plant growth. If the soil condition is poor organic matter can be added at the same time as digging.

The best time to dig is from October through December, when the soil is free of frost and can be left to overwinter. From mid-winter until early spring, the ground is frequently wet or frozen and difficult to work with. Heavy soil must never be dug when it's wet as this can damage the soil structure and lead to poor aeration and drainage.

How to dig

The depth of your topsoil, quality of drainage and whether or not your plot has been previously cultivated, will all determine the digging method required. Single and double digging are the most effective and labour-efficient digging techniques. Before digging, make sure the site is clear of all persistent weeds.

Single digging

Adopt this method on regularly-shaped plots, where it's important that the soil has an even texture. Single digging is also useful when large quantities of organic matter need to be incorporated.

• Dig out trenches to a spade's depth, known as a 'spit', and about 30cm (12in) wide.
• Place the soil from the first trench on the ground in front and work backwards along the plot, turning the soil from each subsequent trench into the one in front.

Double digging

Double digging is useful when drainage needs to be improved, or if the ground has not been previously cultivated. This is a time-consuming process but is worth the hard work and will result in good soil.

• The soil is worked to a depth of two spades, rather than one, and it’s essential to keep the two layers of soil (subsoil and topsoil) separate. In order to do this, the lower half of the trench can be dug over in situ.
• Remove the soil from the upper and lower spits of the first trench and from the upper spit of the second, placing it aside on the ground in three separate, clearly marked piles.
• The soil can then be transferred from the lower spit of the second trench to the base of the first trench, and from the upper spit of the third trench to the top of the first. This ensures that the topsoil and subsoil remain separate.
• Continue digging trenches in the same way, until you reach the end of the bed where soil saved from the first trench can be used to fill the appropriate layers in the final trench.

Simple digging

This method of digging is suitable for cleaning the soil surface of any debris and non-persistent weeds. This is often the best option for working with irregularly-shaped beds or around existing plants.

• Simply lift a spade of soil, invert it and drop it back in its original position.

No dig method

If you suffer from a bad back you may prefer this method over other digging techniques. It's useful for vegetable plots which need organic matter added.

• Ensure your soil is weed-free and level.
• In late autumn, spread manure or compost over the surface of the bed and worms will do the work of incorporating it by taking it down into the soil.
• Further mulch can be applied during the growing season. Repeating this process annually will keep your soil fertile.

Preparing soil for seed

A 'tilth' is a fine soil surface which is essential for seed germination. A surface tilth should guarantee good contact between seed and soil, so that moisture can easily be absorbed.

• Prepare seedbeds about one month before sowing by digging the soil and then leaving it to weather.
• Just before sowing, break up any remaining clumps of soil with a rake, level the ground by lightly treading on it, and rake the surface to give it a fine tilth.