Important Reasons for Xeriscaping

This section features issues important to southern Alberta including but not limited to gardening, native environments, water conservation, water quality and human health. If you have further suggestions, please let us know.

Too much of a good thing: Nutrients

Nutrients from fertilizers are one of the biggest problems in the rivers and reservoirs in the Oldman watershed. Runoff from our lawns and farms carries with it nutrients like phosphorus and nitrogen that cause algae and aquatic plants to grow excessively. If there are too many nutrients and therefore too much growth we see algal blooms that carry with them bacteria harmful to human health. All this plant growth also uses up oxygen in the water, which can kill fish and other aquatic organisms if oxygen levels get too low. You have likely seen unsightly and stinky ponds where there is a lot of plant and algae growth. Prairie Urban Gardens help because native plants do not require chemical fertilizers, using natural manure or compost when and if required. Start making a difference today by following the 7 principles in your yard!

Water Conservation

Southern Alberta's climate is dry and drought is common. Because we live in a naturally dry, grassland environment we need to manage our water carefully to ensure there is enough for the river and the plants, trees, and animals that depend on the river as well as for human needs.

In summer, the highest use of treated water in cities and towns is for watering lawns. The draw on water increases by 50% in summer due to lawn-watering alone. Prairie Urban Gardens can help change this, because once they are established, they require little to no watering. The plants in these gardens are adapted to dry environments and do not need regular or intensive watering to thrive. In fact, over-watering will harm them. Taking small steps like using rain barrels and watering your lawn only 1 inch per week will also help reduce the amount of treated water being used for lawns.


Pesticides are chemicals used to kill insects, vegetation, fungi or rodents. Herbicides (a type of pesticide) only kill vegetation. If you need to use a pesticide, make sure you carefully read and follow the package instructions. Using more than needed or using it more often is not healthy for you, your lawn, or the Oldman River. There are plenty of natural ways to get rid of weeds in your yard.

Manicured, green lawns are a common sight in urban communities and the use of pesticides to keep those lawns pristine and weed free can be just as common. According to a survey conducted by the Oldman Watershed Council’s Urban Team 'The River Starts Here: Lethbridge Stormwater Education Program Design and Evaluation Report', 67% of respondents use a weed-and-feed type product. To reduce the amount of pesticides you use, please avoid these products. “Weed-and-feed” lawn care products contain both herbicides and fertilizers. Many contain more herbicide than is required. It is better for water quality and human health to spot-spray individual weeds with a herbicide or, better yet, to pull weeds out by hand. A spot of vinegar in boiling water can also help. You can also help keep your lawn weed-free by keeping your grass at least 5 cm (2 inches) long and over-seeding the lawn where it is bald or patchy. These areas are where weeds can grow the most easily, but by maintaining consistent grass cover, it will be harder for them to establish.

Excess pesticides from fields, lawns, and gardens can be washed into the street by rain or routine watering, which then runs from the street into a storm drain and directly into a water body such as a river or lake. Water from the gutters empties straight into the Oldman River. Pesticides can also get into local water bodies by way of aquatic application, spills, and even by wind. This can result in a decrease in water quality and harm aquatic flora and fauna.

With growing concerns over the effects of pesticides to water quality and human health, over 100 communities across Canada have restricted non-essential use of toxic lawn and garden chemicals including pesticides. The provinces of Quebec and Ontario have even gone so far as to announce a total ban on pesticide use.


Fertilizers are used to increase or speed up plant growth by providing extra food for the plants. Nitrogen and phosphorus are the nutrients (a.k.a. the plant food) found in all fertilizers, including organic fertilizers such as compost and mulch. Nitrogen and phosphorous are also found in leaves, grass and branches. To help improve water quality, use organic fertilizers such as compost and mulch instead of chemical or inorganic fertilizers. Organic fertilizers release the nutrients slowly over time and are less likely to affect stormwater. The easiest thing to do is leave your grass clippings on the lawn. They act like a mulch and disappear in just a few days. In the fall, rake up the leaves from your yard and put them in a backyard compost bin (available from the City of Lethbridge and local hardware and garden stores). You can then use the resulting compost on your lawn and garden next year!

Did you know?

Early pesticides were mixtures of toxic compounds such as arsenic, mercury, copper, nicotine, and sulfur (Alberta Environment).

A common misconception is that storm drains (aka storm sewers) and sanitation sewers are part of the same underground pipe system that is treated at the wastewater treatment plant. This is actually not the case; storm drains transport water runoff from lawns, gardens, and roadways directly into the river - untreated. It is up to you to help keep your storm drain clear!

Further Learning...

Toronto's Pesticide Bylaw and Natural Lawn and Garden Care

Watch National Geographic's Strange Days on Planet Earth episode titled Troubled Waters for an eye opening documentary of research into why Northern leopard frogs and beluga whales are mysteriously disappearing while swarms of sea stars are overrunning Australia's coral reefs. They ask the question "Has water become a massive delivery system for pollutants?"