Mulching is one of those jobs that can be done at almost any time of year. But I like to do it during the winter months. Here’s why.

The benefits of mulching in winter

  • Spread the gardening workload through the year
  • Easier to apply efficiently when plants are dormant
  • Protects roots of perennial plants from frost
  • Suppresses annual weed seeds
  • Helps to aerate the soil
  • Provides overwintering habitat for essential mini beasts
  • Gradually adds nutrients to the soil
  • Looks neater and more attractive in the winter garden than bare soil
  • Helps prepare the soil for a dry spring or summer 

Make full use of the winter by getting all-weather gardening jobs done

Most gardening jobs are seasonal. Hedge cutting for example is best done outside of bird nesting season. Tender plants need to be planted in spring, autumn is all about clearing leaves and winter is for pruning. But there are a few essential gardening jobs that can be tackled all year round. Driveway cleaning is one, another is mulching.

These early flowering crocus flowers have happily pushed their way through a layer of woodchip mulch. I honestly thing that the colour contrast between the plants and the mulch makes them look all the more vibrant.

The main reason I like to apply a thick layer of mulch in early winter is to make sure that all of those important life forms beneath the soil are protected from frost. That’s worms, soil microbes and of course plant roots. Scientists are certain that subterranean life is even more prolific and important than we know. For starters, soil microbes are responsible for turning dead organic material into plant food – without them we’d be applying many more chemicals to keep our food crops and flowers vibrant and healthy.

As my regular lawn care customers will testify, caring for the soil really is my grass-roots policy for getting the best performance from lawns.  The same ethos applies to the rest of the garden too.

Where to use mulch

  • Around the base of trees. 
  • Perennial Beds and Borders
  • Shrubberies
  • Hedges
  • Overwintering veg beds
  • Around soft fruits

Almost every type of plant will benefit from mulching. In the natural world, it happens all of the time. Leaves fall from trees, vegetation dies back for winter and normally it will just sit at the base of the plant.  Along come the worms, beetles etc and draw the leaves down into the soil for the microbes to recycle it into plant food. However, that doesn’t always work in a garden scenario. Dead vegetation can harbour diseases such as blackspot and, if I’m honest, it’s none too tidy either.

The gardener can replicate Mother Nature’s mulching by removing dead (and potentially diseased) vegetation and replacing it with either compost, leaf mould or bark mulch.

garden robin eating earthworm
Earthworms may not be the cuddliest of garden visitors but they are vitally important for many reasons. Encourage more of them by mulching bare soil.

How will mulch help my garden?

Mother Nature is incredibly clever and very energy efficient. She rarely does anything for the sake of it. If Mother Nature is mulching there’s a good reason for it. In fact there are several reasons.

Soil aeration

Worms, beetles etc are incredibly important for soil health. They’re not there just to tidy away dead leaves, their work performs a vital function. Aerating the soil.

Healthy soil consists of 25% water 25% air and 50% solids. Air and water swish move freely around the solid particles carrying oxygen and plant nutrients with them. If soil is compacted, those spaces are smaller and so the ratios change. In the worst case they could be 90% solid with only 5% each of air and water. That’s not far off rock! Plants simply cannot survive in those conditions.

Worms, beetles  the like do the same job as I do with my lawn aerator – and the same job you do with your garden fork – they open up the soil structure.

Mulch is food for the worms etc. Just as when you feed the birds they appear from nowhere, mulching will attract nature’s soil aerators. And guess what! When you mulch you can put your digging tools away – you’ve effectively delegated the work to Mother Nature!

Retains moisture

My work is mainly in and around Belfast where the soil is clay based. That means that in wet weather it becomes heavy, sticky and hard to work with. In hot dry weather, it bakes to a hard crust.

Mulching clay soil when it’s wet has many benefits. One of which is moisture retention. That layer of mulch shades the surface of the soil. It slows down water loss through evaporation and helps to ensure that plants and anything else living in the soil has the best possible chance of surviving a drought.

Over time, as worms and beetles drag the organic material underground, soil structure improves. The clay particles are less likely to stick together, drainage improves, aeration improves and there is less risk of a hard crust forming in summer.

Weed control

Weed seeds are difficult to avoid. They get blown in on the wind and they are dropped hither and thither by the birds. Most unwanted plant species need light for their seeds to germinate. Mulch – provided it’s thick enough – will block sunlight from any seeds sitting on the surface. Which in turn, means that they won’t grow into weeds. It doesn’t work for every plant species, but it will reduce weeding by a lot. Any that do manage to grow are easily tweaked out of the loose mulch.

Mulching in winter will cover up the seeds that have been dispersed through the summer and autumn. Meaning that they won’t germinate in spring the way that nature intended.

Neat and tidy

Wildlife gardeners tell you to avoid being too neat in your garden. To leave dead vegetation overwinter as hibernating spots for insects. It’s a great idea but not always easy to do. It’s fine for quiet corners out of the line of sight from the house. In more visible areas mulch is a good compromise.

It’s tidier and more attractive than bare soil and somehow a mulched border looks “finished”, cared for and manicured. Plus of course it will still attract insects and minibeasts and the birds that feed on them.

What makes the best mulch?

For mulching around hedges, trees, shrubs, perennials and soft fruit I rather like bark or woodchip mulch. A good grade will keep working hard for 2-3 years.

Try to avoid peat-based composts if you can – they’re not particularly environmentally sound.

How to mulch

Buying (or making) loose mulch wherever possible is a great way to avoid plastic packaging.

Mulching is simply about adding an extra layer to your beds and borders. It can be quite heavy work – it involves lifting, shovelling and some kneeling but the benefits more than make up for the effort.

First, remove all visible weeds and any dead vegetation. If the soil looks as though it is baked hard, loosen the surface a little with a hoe or fork it over.

If your border is beside your lawn, trim the lawn edges so that you have a nice clean line. It will look neater and make mowing easier. You might want to put in some edging strips to give the lawn even better definition.

Working from the back of the border to the front, apply a 5-8 cm deep layer of mulch, be careful not to mulch right up to existing plants. Always leave a 3-4 cm gap around tree trunks, stems and the crowns of herbaceous plants. That little bit of ventilation is vitally important.

Make the mulch as deep as you can. It needs to block all light from annual weed seeds and just like loft insulation, the thicker it is, the more good it will do.

Each year, some of the mulch will be pulled down into the soil. It’s a good idea to add a little extra on top to keep all those benefits working for you.

If you are crossing your lawn with barrows full of mulch and the soil is wet you could cause soil compaction. It’s a good idea to protect the grass by working off boards. In any case, please don’t walk on your lawn if the grass blades are frosted.

One part of the garden where mulching is overkill

There’s an important part of your garden where soil improvement is essential but mulch is generally impractical. I’m talking of course about your lawn.

Instead of mulching, I use a range of treatments to keep lawn soil healthy. In winter time, the most important of these is a seaweed tonic.

Seaweed tonic gives the plants an extra boost, helps strengthen the plants’ resiliance to frost and as an added bonus, really does green up the grass.

Read more in this article

Help with mulching

If you’re not much of a winter gardener, I have some good news for you.  I’m a hardy perennial and happiest when I’m outdoors. I can organise delivery of your bark mulch, apply it for you and tidy up afterwards in little more than the blink of an eye.

I only ever use mulch from a reputable supplier and whenever possible it’ll be locally sourced – no sense in running up big haulage bills. My preferred two grades of mulch are a medium fine texture – which is great for general use and takes a long while to biodegrade. And a fine textured mulch which works well around smaller or more delicate plants.

If you’d like help with mulching, please get in touch. Click here for contact details.

Further reading

Tips to encourage winter wildlife into your garden  

Don’t forget to feed your lawn in winter – here’s what it needs and why