Mulch Time! The Benefits of Mulching

PATRICK J. TURGEON
AVES · JUNE 2020

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Do you mulch when you landscape or garden? If not, you may be making life much more difficult for yourself and your plants. Indeed, mulching can save you time and energy, increase the vitality of your plants, and even make your yard more ecological. Read on to discover more about mulching and how to apply it around a newly planted tree.

Mulching your landscape or garden provides many benefits

What is mulch?

Mulch simply refers to a layer of material that covers the ground around plants in gardens and landscapes. The word ‘mulch’ is derived from the Germanic word ‘molsh’, which means soft. Although not all mulches are soft, the word makes reference to the soft, spongy layer found on a forest floor which it tries to recreate.

In landscaping and gardening, mulch options range from organic materials such as wood chips, hay, grass cuttings, leaves, and bark, to inorganic materials like stones and pebbles, and even synthetic products like plastic chips. Although there is a decorative component to mulch, a mulch should not be chosen based solely on looks, but rather for the functional properties it offers.

Wood chips

Leaves

Pebbles

​What benefits does mulching provide?

Suppresses Weeds: One of the main advantages of mulching is that it prevents weeds from overtaking your planting site. Not only will this save you time and energy from weeding, but it will also help your plants grow by creating a competition-free zone that will allow proper root establishment. The best part is, all of this is achieved without resorting to toxic pesticides.

Maintains Soil Moisture: Covering the ground with mulch helps reduce water evaporation and keep moisture in the ground. For example, a study showed that adding approximately 4 cm of straw reduced evaporation by about 35 percent compared to bare uncovered ground. Coarse organic mulches also act like a sponge and make water available for later use.

Regulates Soil Temperature: Mulch is a good way to insulate the ground and reduce the risk of exposing your plants to temperature shocks from excessive heat in the summer and extreme cold in winter. Both material type and the color of the mulch can play a role in temperature control of the soil.

Improves Soil Quality: Organic mulches slowly decompose and improve the quality of the soil by adding organic matter that keeps the soil loose. As these mulches breakdown, they also release nutrients into the soil that become available for plant growth.

Increases Biodiversity: Organic mulches attract beneficial earthworms, insects, and other soil micro-organisms. These organisms in turn help improve the quality of the soil by aerating it and improving nutrient cycling.

Mulching can foster soil biodiversity

Tips on applying mulch around a newly planted tree:

Donuts, not volcanoes! Apply mulch around a newly planted tree by creating a donut-shaped mound of compacted soil and covering it with mulch. The donut shape will funnel water towards the developing roots. When applying mulch, it is crucial that you do not apply the mulch directly against the stem of a tree! This can cause the stem to become diseased, rot, and die.

Never apply mulch directly against the stem of a tree! Instead, create a donut-shaped mound around it

​Sometimes less is more: You should apply no more than 7.5 cm of mulch.

Keep it on top: A mulch should always be applied on the surface of the ground, not buried or mixed within the soil. Burying or mixing the mulch in the soil could have negative consequences: For example, buried wood chips could cause the amount of available nitrogen to decrease and negatively affect plant growth. 

Before you add: If you are using organic mulches, you will have to replenish the mulch layer every so often since it will decompose. Before adding new mulch, it is important that you mechanically break apart the old layer to ensure it hasn’t become compacted and impervious.

You've read about it, now it's time to apply it. Get out there and mulch!
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Sources:

Bajoriene, K., Jodaugiene, D., Pupaliene, R. and Sinkeviciene, A., 2013. Effect of organic mulches on the content of organic carbon in the soil. Estonian Journal of Ecology, 62(2), p.100.

Borst, H.L. and Woodburn, R., 1942. The effect of mulching and methods of cultivation on runoff and erosion from Muskingum silt loam. Agric. Eng, 23(1), pp.19-22.

Chalker-Scott, L., 2007. Impact of mulches on landscape plants and the environment—a review. Journal of Environmental Horticulture, 25(4), pp.239-249.

Greenly, K.M. and Rakow, D.A., 1995. The effect of wood mulch type and depth on weed and tree growth and certain soil parameters. Journal of Arboriculture, 21, pp.225-225.

Ibarra-Jiménez, L., Zermeño-González, A., Munguia-Lopez, J., Rosario Quezada-Martin, M.A. and De La Rosa-Ibarra, M., 2008. Photosynthesis, soil temperature and yield of cucumber as affected by colored plastic mulch. Acta Agriculturae Scandinavica Section B–Soil and Plant Science, 58(4), pp.372-378.

Patil Shirish, S., Kelkar Tushar, S. and Bhalerao Satish, A., 2013. Mulching: A soil and water conservation practice. Research Journal of Agriculture and Forestry Sciences

Images: 
Wheelbarrow: manfredrichter from Pixabay
Wood Chips: daschi810 from Pixabay
Leaves: JamesDeMers from Pixabay
Pebbles: 272447 from Pixabay
​Robin in Mulch: JakeWilliamHeckey from Pixbay
Volcano and Donut: LEAF photo