What is mulch?
First things first, what is mulch and mulching? A mulch is a loose material, either biodegradable or non-biodegradable, that is used to cover the surface of the soil or compost. Mulching is the act of applying the mulch to an area.
Which mulch should I choose?
Typical biodegradable mulches include bark, wood chips, straw and compost, which will all break down over a period of time and provide additional nutrients to the soil, whilst also improving the structure when it is dug in and replaced.
Non-biodegradable mulches are products such as rubber chips, gravel and slate chippings. These are longer lasting and can be used as decorative mulches, but won’t break down into the soil or provide any nutrients.
When should I apply mulch?
Mulching can be carried out at any time of year, but the ideal times are mid to late spring and autumn, because at these times of year the soil won’t be too dry or cold. Mulch shouldn’t be applied to frozen ground.
In spring/summer, mulch will help to prevent the area drying out, deter some pests, can prevent fruit and vegetables coming into contact with the soil and suppress weeds; in the autumn, applying a mulch will protect the roots of the plants from frost damage as well as enhancing the appearance of the area year-round.
How do I apply mulch?
- Rake (optional)
Before you start, the area should be cleared of any weeds.
Calculate how much mulch you need. The depth should be at least 50mm x length x width of the area, which will give you the volume you need to order. You can use our mulch calculator to help you.
If you’re planting up a new area you may want to consider applying a weed membrane between the soil and the mulch that you can then cut through when placing your plants; a permeable membrane is better as this allows water to pass through it.
Whichever mulch you choose, for optimum results it should be applied over moist soil which isn’t frozen. Most mulches can be easily spread by hand or using a shovel, you can then use a standard rake or the tip of the shovel to level it out.
Care should be taken to ensure you haven’t placed the mulch right up to woody stems or trunks because this can cause them to soften and become vulnerable to disease and rot. Once you are happy with the level of your mulch, check your plants to make sure they aren’t smothered.
How often do I need to reapply mulch?
This can vary depending upon the mulch, whether it is lightweight, biodegradable, non-biodegradable, the environment etc.
Non-biodegradable should only require topping up as you notice the depth starting to reduce, but the old mulch shouldn’t be dug into the soil because it adds no benefit to the soil or plants, won’t break down and will leave you with a stony soil.
Biodegradable mulch will break down over time depending upon the environment it’s in. It can be dug into the soil because when it breaks down it adds nutrients, which can improve the health and structure of the soil. In most cases an annual top up is fine, but you may wish to replenish through the year if you notice areas of soil starting to show through the mulch.
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