Getting started: Soil & Digging
Digging your garden
Cultivating the soil by digging is fundamental to good gardening. Learn the difference between single and double digging and when the no dig method works.
What to do
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 from frost.
- Before digging, make sure the plot is cleared of any weeds.
- Where an even soil structure is important, such as a vegetable garden, single dig the entire plot.
- If the ground has not been previously cultivated, or if drainage needs to be improved, the plot will need double digging which you can learn more about on the next page.
- Simple digging is often the best option for working with irregularly shaped beds or around existing plants.
When to digThe 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
Before digging, make sure the site is clear of all persistent weeds. 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.
Adopt this method on regularly-shaped plots, where it is 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 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.
When digging, many gardeners prefer to simply lift a spade of soil, invert it and drop it back in its original position. This is known as simple digging and is suitable for cleaning the soil surface of any debris and non-persistent weeds. This method is often the best option for working with irregularly-shaped beds or around existing plants.
No dig method
If you suffer from a bad back you may prefer this method over other digging techniques. It is useful for vegetable plots which need organic matter added. Your soil does need to be weed-free and level so this will involve some clearance work. Then, 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.