Spring is here, which means the trees and shrubs aren’t the only things that are blossoming. So too is the itch in every gardener’s mind to start work on this year’s blooms.
We don’t want to prune your enthusiasm, but you might want to sheath the shovel and stow the hoe, as the prevailing wisdom on soil science is to go easy on the earth in your garden.
No-dig gardening is fast becoming the way to grow for soil scientists and horticulturists alike. The rationale is simple: it’s a greener, easier way to grow plants and vegetables.
But why is digging no good?
“Digging disrupts natural processes that keep soil healthy and productive,” says Guy Barter, chief horticulturist at the Royal Horticultural Society (RHS). “Minimising cultivation is desirable when trying to grow plants in ways that have the least environmental impact.”
Digging the soil bulldozes a number of structures underground. Drainage channels created by worms are destroyed, important fungal networks are broken and carbon that’s been locked in the soil is released into the atmosphere.
Digging also brings weed seeds closer to the surface, causing them to sprout more readily.
Barter and his team use no-dig gardening methods at RHS gardens. He says the benefits don’t necessarily include better crops, although other gardeners have reported higher yields.
Charles Dowding, a champion of no-dig gardening, compared side-by-side beds over eight years. One was dug, the other wasn’t. He reported 100kg of additional produce from the no-dig bed.
So how does a no-dig garden grow? Instead of cultivating the soil, no-dig gardeners cover their beds with a layer of mulch or well-rotted organic matter, either from their own compost bins or the garden centre.
If the ground is weedy, simply cover it with a few sheets of cardboard, says Barter. Then add another layer of compost on top (this is sometimes known as lasagne gardening).
“The weeds will be smothered,” Barter says, “and plants root into the soil below, which will be enriched by the activity of worms carrying the compost into the underlying soil.
“There’s no need to use expensive timber to make the beds and they need not be very tall – 15cm (6in) is enough to get the benefits of raised beds. Try not to tread on your beds as this will compact the soil, especially in wet weather, and compacted soil may need to be dug.”
If it all sounds a bit… well, easy, there is another trendy technique to try. Hügelkultur is used to make brownfield sites more fertile. It’s about creating a mound from decaying wood and other compostable matter and then turning that into a raised bed.
“The theory is that decomposing timber supports a wide range of fungi and other organisms that might be beneficial to soil and plant health, and promote good crops,” says Barter.
“Like other raised-bed techniques, it’s especially useful where the underlying soil is poor.”
Barter recommends trying a small patch first, maybe 2m2 (22ft2). Create a shallow trench and fill it with logs, twigs and fallen branches. Add mulch, compost or other organic matter on top and finish with soil.
It’s a low-waste approach to gardening and, like the no-dig method, it simulates what happens in the wild. To date, there has been no robust research into hügelkultur, but rotting timber is thought to promote nutrient-rich soil and it also acts like a sponge, retaining moisture to keep plants watered.
Plus, because the wood takes so long to decompose, the bed should be pushing up daisies (quite literally) for years to come.
Late winter is the perfect time to experiment with no-dig gardening. The ground should be less water-logged and you can prepare your garden just in time for the spring growing season.
It’s not a zero-work approach to gardening, but it’s definitely lazier and more sustainable. Sometimes, it really is easy being green.
About our expert:
Guy Barter is the chief horticultural advisor at the Royal Horticultural Society (RHS). He joined as superintendent of trials at RHS Garden Wisley in 1990, following experience in the commercial horticultural world after graduating with a degree in horticulture. Following this he went on to run the RHS Members' Advisory service. A self-described hands-on gardener who likes to get his boots muddy, Barter grows fruit and vegetables in my spare time and experiments by testing and trying new plants, methods and products.
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