Making the most of the space in your vegetable garden, and maximising yield, is all about taking care of the soil. Living mulches help you to do just that. Mulching garden plants makes a lot of sense. It carries a range of benefits. Mulches can protect the soil from erosion and nutrient depletion, add fertility, conserve soil moisture, and suppress weeds (at least to a degree). But choosing the right mulch for the right situation is crucial.
Most of the mulches typically used in an organic garden – especially in no dig gardens where mulching is a very important practice – will be organic matter. They might be carbon rich organic mulches, like straw or wood chip for example. Or they might be nitrogen rich leafy green mulches. Compost, leaf mould and well-rotted compost are also common mulches that are used.
Living mulches are a little different. They are not dead and decomposing plant material. Below, we will explore what exactly living mulches are. We’ll talk about why using them can be such a good idea. And look at where and when to use them. Then, we’ll talk about a few living mulches that you might find it beneficial to use.
What is a Living Mulch?
A living mulch is a living plant grown to create ground cover between other plants. Typically, it will be grown around annual crops in a vegetable garden during the summer months. The term living mulch is often used interchangeably with the term green manure or cover crop.
But these latter two things are somewhat different. Since they are used to cover an area when you are not growing annual crops (over the winter months, or during a gap in crop rotation). Green manures and cover crops are typically chopped and dropped to provide nutrients to the system.
A living mulch on the other hand, while it may also be chopped and dropped when no longer required, is primarily used for the benefits it provides while it is growing.
Why Use a Living Mulch?
A living mulch can be beneficial in a number of different ways. It can, of course, serve many of the same functions as other types of mulch, like compost, straw etc.. It can protect the soil, conserve moisture and prevent weeds. Some (such as nitrogen fixers) may even add fertility while in active growth. But a well chosen living mulch can do more.
One thing to think about is that a living mulch will sequester carbon from the air – increasing the amount of carbon that is drawn down into the soil. And therefore, using living mulches can be one more step gardeners can take to help combat our climate crisis.
Another thing to think about is biodiversity. When we use living plants rather than organic matter to mulch in a vegetable garden, this can also draw wildlife in.
A living mulch is a specific type of companion planting. The plants are specifically chosen to cover and protect the soil. But they can also aid the crops that they are grown between in other ways. For example, they can attract bees and other pollinators. Or other beneficial insects which help to keep sap-sucking pests population numbers down. Such as ladybirds and hover flies, for example. They might also help in drawing other beneficial wildlife to the garden.
Some living mulches might also help keep away, confuse or distract unwanted pest species. So might help in keeping your main crops safe.
Where and When to Use Living Mulches
Living mulches can be used around annual crops in a vegetable garden, in perennial planting schemes, in orchards, on sloping sites (to stabilise the soil) and in a range of other situations in a garden.
But choosing the right living mulch for the right situation is crucial. Not all living mulches will be suitable for use in a particular place. As a gardener, you have to select these companion plants very carefully to achieve your desired goals.
Firstly, and most importantly, you need to consider competition. The crucial thing to ensure is that the living mulch you choose will not compete too much with the plants that they are placed between. Considering growth habit and form, root systems (and their depth) water and nutrient needs and other factors will help you determine whether or not specific living mulches will work well around the other plants you are growing.
You also need to think about when a living mulch is sown. This is especially important where you are growing a living mulch around the crops in a vegetable garden. And you also need to think about whether you want a living mulch that is annual (and remain for just one season) or will choose a perennial living mulch that will be used for a longer period of time.
Examples of Living Mulches
There are plenty of examples of annual, biennial and perennial living mulches to consider for different locations around your garden.
In vegetable beds, some living mulches to consider include:
Clovers (which fix nitrogen)
Alfalfa (another nitrogen fixer)
Phacelia (great for bees and other pollinators)
Sweet alyssum (also great for pollinators)
Chickweed (great ground cover, good for pollinators and edible too)
Purslane (another edible ‘weed’ that may not outcompete deeper rooted crops)
Creeping thyme (great for attracting wildlife etc..) (Or other low-growing aromatic herbs)
Though do bear in mind that the above will not work in all situations, and will not make the best companions for all the crops you may grow.
Often, companion planting with living mulches takes some experimentation, and trial and error to see what works well in your particular situation – in your particular garden. I have found chickweed to be a useful living mulch, and allow it to grow beneath a number of common crops in my polytunnel.
Remember, the key is to balance potential competition with the benefits to be gained. Sometimes it is a delicate balancing act. But thinking about how the plants grow, and the depth and spread of their root systems can help you to make the right choices.
Living mulches will not always be the best choice for your vegetable garden. But when you select the right plants and use them judiciously, they can be a great type of mulch to use in your garden.
We’ll love to hear about companion planting combinations and living mulches that work well for you where you live. So please do share your own experiences in the comments below. You can help other gardeners find the right soil-protecting solutions for their own gardens by sharing your own experiences and advice.
Elizabeth Waddington is a writer and green living consultant living in Scotland. Permaculture and sustainability are at the heart of everything she does, from designing gardens and farms around the world, to inspiring and facilitating positive change for small companies and individuals.
She also works on her own property, where she grows fruit and vegetables, keeps chickens and is working on the eco-renovation of an old stone barn.
To get in touch, visit https://ewspconsultancy.com.