Mulching Guidance

Mulching is generally used to improve the soil around plants, but it also gives your garden a neat, tidy appearance and can reduce the amount of time spent on tasks such as watering and weeding. Mulches help soil retain moisture in summer, prevent weeds from growing and protect plant roots in winter.

Mulching Benefits

• Help soils retain moisture in summer
• Suppress weeds
• Improve soil texture
• Deter some pests
• Protect plant roots from extreme temperatures
• Encourage beneficial soil organisms
• Provide a barrier for edible crops coming into contact with soil
• Give a decorative finish

Types of Mulch

Biodegradable mulches break down gradually to release nutrients into the soil and help improve its structure. This kind of mulch will need to be replaced once the material has fully decomposed. Biodegradable mulches include leaf mould, garden compost, spent mushroom compost, wood chippings, processed conifer bark, well rotted manure, straw (for strawberries), spent hops (poisonous if eaten by dogs) and seaweed.

Non-biodegradable mulches do not add nutrients or improve soil structure, but they do help to suppress weeds, conserve moisture and can look decorative. Slate, shingle, pebbles, gravel, stone chippings and other decorative aggregates are often used as a mulch across beds. Crushed CDs, sea shells, tumbled glass and similar materials can be used on the surface of containers.

Sheet mulches or woven landscape fabric are ideal for new beds or borders. After laying, slits can be made in the fabric, allowing direct planting through it. However, these mulches do not look very attractive, but they can be decorated with gravel, bark or others materials. Permeable materials are best in order to allow rain and irrigation water to reach the roots.

Always ensure that the material you choose as your mulch is good quality - poor quality can introduce pests or diseases to your garden.

When to Apply Mulch

Mulches are best applied when the soil is moist and warm, usually from mid- to late spring and autumn. It is best to avoid applying mulches in winter and early spring as the soil is too cold, and in summer, when it will be dry. They can be applied around new plantings or to established beds and specimen plants.

How to Apply Mulch

Mulch can be placed over entire beds and borders, but one should be careful to avoid smothering low growing plants and to ensure the material does not pile up against woody stems. Biodegradable mulches should be applied at a thickness of between 5cm (2in) and 7.5cm (3in) thick. All weeds should be removed from the soil before laying the mulch and it is best to apply the mulch over moist soil.

It is vital to ensure that the mulch is not in direct contact with plant stems because it can cause the stem to soften, which will make it vulnerable to disease.