There are more microorganisms in a teaspoon of healthy topsoil than there are people on earth. Yes, you read that right! And it is this life that we should always try to work with when creating a sustainable garden. Truth be told, you do not need any shop bought mycorrhizal fungi nor do you need to spend the entire winter turning farmyard manure to create compost. It is a lot simpler than that. Put away your spade and mulch – nature will do the rest.
After trailing many labour-intensive methods to improve the soil, I can confirm that to start a border or vegetable patch from scratch or improve an existing one, simply remove any weeds and then mulch. If in doubt, mulch some more.
The mulch is placed on top of the soil. The microorganisms in the soil slowly pull it down, up to three metres below the surface. These organisms include fungi, bacteria, protozoa, nematodes, and algae. They eat plants, they eat each other, they die. And throughout this repeating life cycle, they regenerate topsoil which stores carbon, retains water, helps plants fight off harmful microorganisms, and creates a layer of humous full of nutrients available to the plants.
I advise a layer of 15cm of mulch, more in areas with stubborn weeds. When planting or sowing, push some of the mulch aside. Once the plant is established or has grown enough, push the mulch back. It reduces the amount of weeding and does so much for the health of the soil.
Types of Mulch
The best mulch is coarse and has a good mixture of carbon and nitrogen. Woodchips that contain the whole tree or shrub, including the green, are best and tree surgeons often sell it by the cubic metre.
If you use compost made from garden and kitchen waste, then that is plenty for your vegetable garden. Stopping green waste from going into landfill, where it produces methane, is only a great thing for our planet.
Many advise putting a layer of cardboard down to stop light coming through the mulch and to suppress perennial weeds. I have certainly advised it previously but with poor results. In my experience, it does little to deter perennial weeds. All it does is stop gasses flowing between the soil and the air. The soil is full of life and just like us, air is needed. You often, after applying cardboard, see worms come very close to the surface. I have heard it being used as an argument for how much good the cardboard is doing because worms are good. Recently, however, I learned that if worms are coming that close to the surface, they are more likely to be deprived of fresh air and had to come up.
The best way to make good compost from your garden is to store things separately. A brown heap with any organic carbon rich material including paper, and a green heap. Then when you have enough, mix them. At least half, but if possible more like three quarters, should be brown material. Make sure that, as you build the heap up, you keep it moist.
Then there is one secret to it working: turn it regularly. You will see the heap heat up and in winter you can see the steam come off. As it cools down, turn the heap, mixing everything through again. And that is it. In Scotland, compost heaps can take a bit longer because of the colder temperatures so take your time, it will eventually happen.
Leaves are often advised to be kept in a separate bag to make leaf mould. I simply rake them into my flower beds and leave them there to mulch in place. It is great for wildlife to have the soil covered with leaves, as it should be. And it saves me some work.
Digging, instead of mulching, drastically compacts soil: it destroys the invisible fungal webs and tunnels under the soil and releases carbon into the air, and it can be back breaking work. Of course, when you dig up your potato patch you will have to do a bit of digging but try to do it as little as possible.
I should be honest, though, I am a garden designer. To create my visions, there often is hard landscaping to be done and, yes, digging. If you do dig, be mindful of the impact. This starts with a good design, including the selection of the right, long-lasting materials and proper installation. That way, after the initial digging, you can leave your spade in the shed and enjoy a new no dig era of gardening.
Katrina Flad runs her sustainable garden design and landscaping business frock n wellies from her home in Aberdeenshire. Passionate about the planet and all things that live on it, she wanted to make a real difference to her environment ever since she can remember. In her regular column, Katrina will bring you design solutions for your garden which are sustainable, practical, and beautiful. Follow Katrina at frock n wellies on Instagramand Facebook.