Mulch is a thick layer of material placed over the soil and around plants, used to lock moisture into the soil while acting as a physical barrier to drying winds and direct sun. Some mulches also contain nutrients, acting as slow-release plant food. As worms take the mulch into the soil they help to improve soil structure, making it more moisture retentive, free-draining and fertile.
There’s a variety of mulches to use – both organic and inorganic – which have different uses in the garden. Organic mulches are made from dead plant material such as compost, leaves, bark or grass clippings. Inorganic mulches are made from stones or gravel. While some mulches are better for certain jobs than others, most mulches have a positive benefit on the garden, wherever you use it.
How to mulch
The best time of year to mulch is spring and autumn. Water the area thoroughly before mulching, so the mulch keeps the moisture in the soil. Add a thick layer of material to the soil – the thicker the layer, the more weeds will be suppressed. Use your hands or a spade to add the mulch, depending on the material you choose. Finally, use a rake or hoe to make sure the mulch is evenly distributed.
More on mulch and mulching:
We’ve picked five organic mulches to use, to boost your soil and keep weeds down.
Low in nutrients and an excellent soil conditioner, leaf mould provides a quick reward for a little effort – simply bag up leaves in autumn and they should be ready to mulch around your plants after around 12 months.
Buy compostable bags for your leaves from Waitrose Garden
Well-rotted horse manure
Well-rotted horse manure is packed with nutrients and retains moisture well. It’s excellent for mulching around hungry plants like roses and edibles, especially pumpkins and squashes. Make sure it’s been left to rot for at least two years, otherwise it can ‘scorch’ plant leaves and even remove nutrients from the soil as it breaks down.
Buy organic farmyard manure on Amazon
One of the benefits of using composted woodchips is that their darker colour and smaller particle size looks more natural than large woodchips. Also, given their bulkiness, they’re ideal for improving soil structure by improving drainage and making it more moisture retentive.
Buy composted wood chips from Wickes
Homemade garden compost is a good all-round mulch – great for retaining moisture, suppressing weeds and soil improvement. Add kitchen scraps and chopped up garden waste to your compost bin and turn every few months. You should have a useable compost between six and 12 months later.
Buy compost bins and bays on Amazon
Five mulches to use – spent mushroom compost
Mushroom compost, often bought as ‘spent’ mushroom compost is alkaline, light and easy to use. Given its high pH, it’s ideal for lime-loving vegetables, including brassicas like kale, cabbages and broccoli. Avoid using on lime-hating, ericaceous plants like rhododendrons, camellias and heathers.