What is mulching?
Mulching your garden is when you add a thick layer of organic matter (usually manure, compost or bark) on the surface, this will help to retain soil moisture, suppress weeds, add nutrients and insulate plant roots.
Mulch can be attractive too, so you might want to try decorative bark or woodchip mulch. Each will provide an attractive surface that adds a decorative and useful finish to flower beds, around the base of trees and along the edges of paths. Make sure you water the ground thoroughly before you add your layer of mulch. Remember you need to trap the moisture in the soil so there must be moisture there first!
Why do you mulch soils?
Mulching your soil is an important step for improving the structure of your soil ensuring it can hold on to more nutrients and moisture . You may think that you are only placing a blanket over your soil, but in fact, the mulches are breaking down and releasing valuable nutrients. So one simple act will improve your soil, keep weeds at bay and make your beds and borders look far better.
Why do soils need improving?
Clay soils: Although clay soils hold nutrients well, they are heavy, slow to warm up and tend to be too wet (sticky) in the winter and too dry (rock hard) in the summer. The key to improving these soils is to break up the mass and increase aeration and drainage by adding composted soil conditioner to achieve a crumb-like texture.
Silty soils: Silt particles are extremely fine and tend to rise to the soil surface forming a water-resistant crust when dry. Adding soil improver will help with the structure and allow water to penetrate.
Sandy soils: These are very light, easily eroded, dry and lack substance and the ability to hold water or nutrients. Soil improvers help to retain moisture and nutrients before they leach away.
Regular mulching will help improve all these soil types and give you much stronger, healthier plants - with the added benefit of reducing weed growth!
Different types of mulch
There are many different organic mulches available, the best ones will form a dense cover holding in water and gradually breaking down to release nutrients into the soil. Well, rotted Farmyard Manure is often used and is great for keeping weeds off empty beds that are resting over winter, waiting for their spring planting. When you are ready to plant simply lightly fork the manure in and you have a well fertilised, weed-free soil to start planting up.
Leaf mulch is used in a similar way and can easily be made at home by having a separate compost bin just to collect leaves in. The leaves rot down over the year and produce a lovely organic mulch, and it's free! Composted bark is another good choice.
Wood chip mulch is a popular option, it can come in a range of sizes and styles. Pine bark nuggets tend to be viewed as the most attractive of the barks, with the stripped bark similar to the type you see in children’s play areas being the cheapest option. Pine bark should only be used on paths and not for mulching beds and borders.
Read our guide to know more about making your own mulch in autumn.
How to apply mulch
- Clear the site of all weeds.
- If the ground is dry, water thoroughly.
- Cover the area in a layer of your chosen garden mulch.
- Make sure the area has a mulch depth of at least 2cm (5").
- Clear the mulch away from the stems of the plants.
- Use a rake to gently level the surface.
Frequently asked questions about how to mulch your garden
Is mulch the same as compost?
No, mulch and compost are two different things. Mulch can be organic or inorganic materials that haven’t yet decomposed, whilst compost is made up of decomposed organic materials. You also use mulch on the top layer of the soil to retain moisture, suppress weeds and protect plant roots. Compost is generally dug into the soil to improve structure and nutrient level.
What should you not mulch?
Mulch is generally fine if you lay it correctly. However, if mulch is in direct contact with plant stems it can cause rotting which can lead to disease. Try not to mulch Mediterranean plants such as lavenders and rosemary as they do not like or need the extra moisture or nutrients.
What are the methods of mulching?
When it comes to mulching, we recommend that you thoroughly clear the site of all weeds and water the ground. You should then cover the area in a layer of your chosen mulch to a depth of at least 2 inches (5cm). Clear the mulch away from plant stems and use a rake to level the surface gently.