What Is Mulch?

Mulches are loose coverings of sheets or materials that are placed on the surface of soil. They can be applied to bare soil, or to cover the surface of compost in containers. Beyond its practical benefits, mulch gives gardens a clean, well-kept appearance. During the winter months, mulching becomes especially valuable, as it provides insulation that protects roots from freezing temperatures and reduces damage from repeated cycles of freezing and thawing.

You can mulch all year round, with different benefits for mulching in spring and summer to mulching in autumn and winter. Winter is a great time to mulch as your beds are clear and plants are dying back for winter. There are also loads of different types of mulches, so check out our range of Mulches here.

Benefits Of Mulching

• Moisture retention, as mulch helps the soil hold water by reducing evaporation, which means less frequent watering is needed
• Natural weed barrier, blocking sunlight from reaching weed seeds and making it harder for them to grow
• Mulch regulates soil temperature, keeping roots cooler during hot summers and warmer during cold winters, which helps reduce stress on plants
• Mulch also prevents erosion, reduces soil compaction from heavy rain, and gives garden beds a tidy, finished look
• Mulch encourages worms to do the work for you; they drag the nutrients from organic mulch into the soil. This helps to improve soil structure by making it more moisture retentive, free-draining, and fertile.

When To Apply Winter Mulch?

Winter mulch should be applied after the ground has started to cool but before it freezes solid, usually in late fall. The goal isn’t to keep the soil warm all winter, but to keep the temperature consistent and protect roots from damage caused by frequent freezing and thawing. If mulch is put down too early, when the soil is still warm, it can trap heat and encourage plants to keep growing instead of going dormant, which makes them more vulnerable once the cold sets in.

A good rule of thumb is to wait until after the first hard frost, when night time temperatures are regularly below freezing and plants have died back or gone dormant. At this point, you can spread a thick layer of mulch (typically 2 to 4 inches) around the base of perennials, shrubs, and trees. Be careful not to pile mulch directly against stems or trunks, as this can trap moisture and cause rot. For tender plants, a slightly thicker layer may be needed, while hardy trees and shrubs may require less.

How & Where To Apply Mulch

When applying mulch, it pays to prepare the soil beforehand. This will save you time and effort in the long run:

• Fork out perennial weeds and pull out annuals by hand
• Rake the surface of the soil to level out dips and hollows, then re-firm as necessary
• Water thoroughly to ensure the soil is moist before applying the mulch, so the mulch keeps the water in the soil

Applying mulch is easy – simply lay 2-4 inches of your chosen mulch onto the bed or around key plants, without smothering them or damaging the lower stems. Bear in mind that a really thick layer of mulch will suppress more weeds, but bulbs and other plants will find it hard to grow through more than a 5cm layer. 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.

Around spring bulbs – mulching around spring bulbs as the foliage dies back will feed the bulbs and lock in moisture just when they need it. Mulching will also reduce the need for digging, which can easily lead to bulb damage.

Under hedges – apart from regular clipping, hedges are often ignored. Their roots are packed together, and benefit from an annual mulch to lock in moisture and feed the plants. Make sure the soil is moist or water well before mulching.

Around herbaceous perennials – dark organic mulch visually sets off herbaceous perennials. If you’ve just divided and watered them, then mulching around the new plants will give them a boost as the growing season gets going.

Around fruit trees and bushes – fruit trees and bushes need plenty of moisture around their roots, especially when fruit is forming. A regular mulch will suppress weeds and help keep the plants healthy and resistant to pests and diseases.