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Using Mulch for Gardening Success

A thick layer of material placed over the soil and around plants is called mulch. Used to keep weeds under control and keep moisture in the soil while also preventing drying winds and direct sunlight. Additionally, mulches contain nutrients that act as slow-release plant food. They attract worms, beetles, and other soil invertebrates as they break down, which provides birds with food.

A layer of mulch surrounding rose shrubs
A layer of mulch surrounding rose shrubs

What is mulch?

Mulches are free covers or sheets of material put on the outer layer of soil. These can be applied to uncovered soil or to cover the outer layer of fertiliser in compartments.

Mulching can have a number of advantages, depending on the kind used. Some of these include helping the soil retain moisture, reducing the need to water, and suppressing weeds. In addition to increasing the organic matter in the soil, it also provides nutrients, repels some pests, and warms up in the spring. Additionally, mulching shields plant roots from extreme heat and cold, promotes beneficial soil organisms, prevents edible crops from coming into contact with the soil, and can add decorative value to the garden.

Mulches can be broken down into two main categories: non-biodegradable as well as biodegradable Both types conserve moisture by reducing evaporation from the soil surface and suppress weeds by blocking sunlight, which is required for weed seeds to germinate and grow.


These gradually decompose to release nutrients into the soil and contribute to its improved structure. When the material has completely rotted down, the layer will need to be replaced. Garden compost, wood chippings, processed conifer bark, leaf mould, well-rotted manure, straw for strawberries, and seaweed are among the best materials.


Mulches that are not biodegradable do not improve the structure or fertility of the soil, but they do control weeds, conserve moisture, and some even look decorative. Mulch is frequently applied to beds in the form of decorative aggregates like slate, shingle, pebbles, gravel, and stone chips. Containers can be decorated with seashells, tumbled grass, and other similar materials, but it’s best not to use anything made of plastic. In strong sunlight, dark materials will warm the soil, whereas white gravel, a light-coloured mulch, will reflect light and keep roots cooler.

New borders or beds can be made from sheet materials or woven landscape fabric. Silts can be made in the fabric after it is laid, making it possible to plant directly through it. These mulches have the drawback of not being very attractive, but they can be disguised with gravel, bark, or other materials. Always select a sheet that is permeable so that irrigation and rainwater can reach the roots, as a waterproof layer may cause drainage and surface runoff issues elsewhere.

When to apply mulch

The best times to apply mulches are in the middle of the spring and autumn, when herbaceous plants are dormant and annual weeds have not yet germinated. They can be used on new plantings, beds with existing plants, and specimen plants. Mulching can be applied to newly established plants at any time of the year, when they will benefit from soil moisture retention and weed suppression.

How to apply mulch

Mulch can be used completely in beds and borders, but be careful not to smother plants that are just starting to grow or to pile mulch up against the stems of woody plants. Biodegradable mulches need to be between at least 5 cm and 7.5 cm thick to be effective. After weeding, when the soil is not frozen, spread mulches over moist soil. Planting through mulch sheets is efficient when making new beds. Mulching specimen shrubs and single trees should be applied to the canopy’s radius. Your plants and soil microorganisms will be fed by a biodegradable mulch as it decomposes over time, eliminating the need for additional soluble feed. Mediterranean plants that cover the ground should probably not be mulched because the stems and foliage can hold too much moisture.

How to make your own mulch

Composting garden and kitchen waste can be used to make mulch on your own. Additionally, you can make your own leaf mould. We have a selection of articles around composting here.


Mulching typically poses no problems if laid correctly. However, if they come into direct contact with the stems of specimen trees or shrubs, they may soften the stems and make them more susceptible to diseases.

The choice of organic material has less impact on water conservation and weed suppression than applying a sufficient layer. Weeds will be blocked from sunlight by thicker layers, which will improve soil insulation and reduce water loss.

If you add mulch to the soil, you may need to water more to get to the plants’ roots below. However, the mulch will also help rain soak into the soil and less water will evaporate, so you should need to water less often.

Frequently Asked Questions

Is mulch better than compost?

“Compost is the most effective method for enhancing the structure of the soil and adding nutrients to it. Mulch is the best mulch for preserving soil moisture, preventing weed growth, and preventing erosion. Compost is made of decomposed organic materials; Mulch, on the other hand, can be made of materials that have not yet broken down, either organically or inorganically,” says Chris Bonnett, gardening expert for The Express.

Where should you not use mulch?

“In addition to keeping mulch away from tree trunks, you should ensure that it does not accumulate at the base of shrubs, particularly surface-rooted bushes like azaleas and boxwood. Mulch piled up against shrubs will encourage the growth of roots,” says Chris Bonnett, gardening expert for The Express.

Should I remove old mulch before planting?

“Should old mulch then be disposed of? Experts with green thumbs argue that it is completely unnecessary to remove mulch from the previous year. As the mulch decomposes over time, beneficial nutrients and other organic matter are added to the soil. Taking out the mulch that is already there every year will only add labour and cost more than is necessary,” says Chris Bonnett, gardening expert for The Express.

Updated on April 12, 2023

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