By Brianna van de Wijngaard,

Community Liaison, Cariboo Chilcotin Conservation Society —


A bed of Lacinato kale mulched with leaf litter. Photo: Russell Nursery, North Saanich, BC.
A bed of Lacinato kale mulched with leaf litter. Photo: Russell Nursery, North Saanich, BC.


Here at the Water Wise headquarters, in the basement of the Phoenix building, we’re always trying to find ways to decrease summer water use, because it increases so much in July and August—up to 50 per cent, compared to other months. Of course, some of the primary culprits are lawns and gardens, and – as many of you know – there are ways we can have both. This how-to piece is on mulching, arguably one of the top dogs of garden tasks.


Mulching for Water Conservation

Mulching holds more water in the soil for longer periods of time, so the amount and frequency with which you water is less. Simple as that. When you don’t mulch, you can lose up to 35 per cent of the moisture in your soil to evaporation, as well as introduce a number of other problems, such as compaction, erosion, and weed growth, noted below.

It’s best if you can lay drip tape under the mulch, rather than water from overhead, as this will penetrate the soil better (especially if you use a less permeable mulch, such as polyethylene plastic). But organic mulches, such as lawn clippings or leaf litter, can also hold water for later release.


Other Benefits of Mulching:

Reduced Erosion and Compaction

Elements like wind, rain, and foot traffic are hard on soil. That’s why it’s rarely bare in nature. Protecting from these elements with a mulch will lessen stress on plant roots, and improve plant health.


Maintenance of Optimal Soil Temperatures

Mulches act like insulation for the soil, buffering fine roots from extreme temperature fluctuations. This is most important for new seedlings and transplants that have not yet grown a more established root system. It also keeps soil cooler in hot conditions and warmer in cool conditions.


Increased Soil Nutrition

Living and organic mulches can increase soil fertility depending on the mulch type, soil chemistry, and the particular nutrients of interest. Some examples of living and organic mulches are grass clippings, manure, leaf litter, and straw. Be sure to use certain mulches such as manure sparingly, so as to not over-fertilize a given area of your garden.


Improved plant establishment and growth

Mulches are used to enhance the establishment of many woody and herbaceous species. According to an article titled, “Impact of Mulches on Landscape Plants and the Environment” which appeared in Journal of Environmental Horticulture, there are hundreds of controlled studies demonstrating that mulches improve seed germination and seedling survival, enhance root establishment and transplant survival, and increase overall plant performance when compared to unmulched controls. This means healthier full-grown plants.


Disease Reduction

Mulches prevent overhead irrigation from splashing onto plant stems and foliage. This is important because water (rain or tap) can carry spores of disease organisms, and/or create ideal environments in which disease can flourish. Mulch will also protect microbial populations which can then suppress soil pathogens through either direct competition, or chemical inhibition. Selecting the proper mulch in this case is important, however—plastic mulch with wood chips, for example, has been shown to increase certain plant diseases.


Weed Control

Quite simply, mulches block more light than the soil (and weed seeds within it) would get otherwise, thus inhibiting germination.

So mulching not only saves water. It saves time and your plants, too. If you’d like more info on Water Wise gardening, check out our tips and info found at!water-wise/c7ss. Thanks for being Water Wise this summer!


Brianna van de Wijngaard is the Community Liaison for the Cariboo Chilcotin Conservation Society. She manages the organization’s website, social media, communications, and lots of Water and Waste Wise event and project planning. Check out their work at



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