How deep should mulch be laid and when will it need to be topped up?

Generally, I suggest a minimum depth of 50mm to 75mm but you should note that optimum depth will depend on the type and particle size of the mulching material used.

Light aids the germination of many weed seeds and any tiny seedlings receiving light will romp away, so the aim is to create a layer through which light cannot penetrate.

If the mulch particles are of a consistently large size, then a greater depth will be needed to prevent the light travelling through the gaps between the pieces. Smaller particles are better at fitting together to form a barrier, so 50mm may be adequate.

Topping up will depend on the type of mulch and its constituents, plus the prevailing conditions. In any case, it will be necessary to inspect the mulch 30 days after laying and top it up to compensate for settlement, a factor that can vary from five per cent for a good-quality bark mulch of uniform particle size to 20 per cent for mixed woodchips and composted green-waste mulches. The longevity of mulch will also depend on the type of material. Graded bark, such as Melcourt Industries' Nuggets and similar products from other firms, should be good for four or more years.

Topping up will be necessary to replace material dispersed by feet, wind or heavy rainfall. Where the mulch comprises a mixture of wood-fibre materials, and especially where there is a large range of particle sizes and some dust and fines content, then you are probably looking at replacement after two or perhaps three years. Composted materials give the shortest mulch life - sometimes as short as 12 months.


Have you registered with us yet?

Register now to enjoy more articles and free email bulletins

Sign up now
Already registered?
Sign in

Before commenting please read our rules for commenting on articles.

If you see a comment you find offensive, you can flag it as inappropriate. In the top right-hand corner of an individual comment, you will see 'flag as inappropriate'. Clicking this prompts us to review the comment. For further information see our rules for commenting on articles.

comments powered by Disqus

Read These Next

Tomorrow's tractors

Tomorrow's tractors

These machines have advanced rapidly over recent years but what does the future hold? Sally Drury looks ahead.

Tractors - Maintenance models

Tractors - Maintenance models

The tractors chosen by professionals across the sector reflect the best features, backup and support on offer, says Sally Drury.

Guide to Glee 2017

Guide to Glee 2017

A vast array of new garden products will be displayed at this year's show. Matthew Appleby previews what visitors can expect to see.


Horticulture Jobs
More Horticulture Jobs

Industry Data

An exclusive report for HW subscribers revealing the key development trends, clients and locations for 2017.

Are you a landscape supplier?

Horticulture Week Landscape Project Leads

If so, you should be receiving our new service for Horticulture Week subscribers delivering landscape project leads from live, approved, planning applications across the UK.

Landscape Contracts & Tenders

Products & Kit Resources

BALI National Landscape Awards 2016

Read all about the winning projects in the awards, run in association with Horticulture Week.

Noel Farrer

Founding partner of Farrer Huxley Associates Noel Farrer on landscape and green space
 

Read Noel Farrer