In the summer months, municipal water use doubles. This is the season when Canadians are outdoors watering lawns and gardens, filling swimming pools and washing cars. Summer peak demand places stress on municipal water systems and increases costs for tax payers and water users. As water supplies diminish during periods of low rainfall, some municipalities must declare restrictions on lawn and garden watering. By applying some handy tips, your lawn and garden can cope with drought conditions and you can minimize water wastage.
Much of the summer peak demand is attributed to lawn and garden watering. Often water is applied inefficiently, resulting in significant wastage due to over watering, evaporation or run-off. Here are some general watering tips to help avoid wastage:
- Before watering, always take into account the amount of water Mother Nature has supplied to your lawn or garden in the preceding week. Leave a measuring container in the yard to help you monitor the amount of rainfall (empty it once per week) and follow the tips below to help determine how much water to add. Also bear in mind any watering restrictions that may apply in your municipality.
- Water in the early morning, before 9 a.m., to reduce evaporation and scorching of leaves from the sun. Water on calm days to prevent wind drift and evaporation.
- Set up your sprinkler or hose to avoid watering hard surfaces such as driveways and patios. If you’re not careful, it’s water and money down the drain.
- Water slowly to avoid run-off and to ensure the soil absorbs the water.
- Regularly check your hose or irrigation equipment for leaks or blockages.
- Collect rainwater from your roof in a rain barrel or other large container and keep it covered with an insect screen. Direct the down spout of your eavestroughs into the rain barrel.
- Choose an efficient irrigation system. A soaker hose placed at the base of plants on the ground applies water to the soil where it is needed — rather than to the leaves — and reduces evaporation (see Figure 1). Drip or trickle irrigation systems are highly efficient because they deliver water slowly and directly to the roots under the soil surface. This promotes deeper roots, which improve a plant’s drought resiliency. If you use a sprinkler, choose one with a timer and that sprays close to the ground.
Figure 1: Soaker hoses have tiny pores that emit water slowly and directly to the soil. Place them at the base of plants on the ground.
Tips for Your Lawn
Established lawns1 generally require about 2.5 cm (1 in.) of water per week to thrive.2 If Mother Nature is providing this amount of rainfall, your lawn will thrive without supplemental watering. When rainfall does not provide adequate moisture, your grass may start to turn brown. This does not mean it is dead — it’s simply dormant. An established lawn will recover and resume its green appearance shortly after sufficient rainfall returns.
Apply these tips to save water and money without compromising the health of your lawn:
- Apply about 2.5 cm (1 in.) of water not more than once per week and skip a week after a good rain. The correct amount can be estimated by placing an empty tuna can on your lawn as you apply water evenly across the surface. When the water level reaches the top of the can, you’ve applied about 2.5 cm (1 in.) of water which is all your lawn needs. You can time how long it takes to reach this level, then set the timer on your sprinkler.
- Water thoroughly. Deep watering at this rate is better than frequent, shallow watering because it encourages deep roots.
- Don’t water your lawn excessively. When it’s waterlogged, it may turn yellow and develop fungus and diseases. Oxygen and mineral uptake may be restricted on heavy clay soils. Too much watering can also lead to thatch and fertilizer leaching.
- Check with your municipality to see if watering restrictions are in effect.
- Avoid mowing and unnecessary traffic on your lawn when the lawn is dry or dormant.
- Don’t cut your lawn too short. Set the blade on your lawn mower to cut no lower than 6 to 8 cm (2.5 to 3 in.) so that the roots are shaded and better able to hold water.
- Aerate your lawn once a year in the early spring or fall to improve water penetration. Afterwards, top-dress by applying a thin layer (max. 15 mm — 0.6 in.) of organic material and rake to distribute evenly. You can overseed after this to help thicken the lawn.
- A thick, vigorous lawn is the best prevention against weed invasions and can better withstand heat and dryness. A healthy lawn needs nutrients, such as nitrogen. Application rates, sources and timing will depend on many factors including soil type. As a rule, a healthy lawn with good soil needs about ½ kg (1 lb.) of nitrogen per 100 sq. m. (1,075 sq. ft.) of lawn area every year. Leave grass clippings on the lawn to return nitrogen to the lawn, and reduce moisture loss.
1 Newly seeded or sodded lawns have greater water demands.
2 Actual water requirements depend on individual conditions, such as soil type.
Tips for Trees, Shrubs and Flower Gardens
Here are some water-saving tips for trees, shrubs and flower gardens:
- Direct water to the root system. In the case of trees and shrubs, the roots that take up the most water are generally located within the top 30 cm (12 in.) of the soil and near and even beyond the drip line. This is the area directly below the outer tips of the branches.
- Plants have different watering requirements at various stages of their growth. Keep soil moist in the first growing season. One rule of thumb is to water trees with a one-hour trickle using a soaker hose at least once per week, barring a good rainfall and more frequently during hot weather. Taper off watering in the fall. In the second growing season, water twice per month in late spring and summer. Once established, trees that are well-selected should require little or no watering other than that provided by rainfall, but ensure they get adequate watering during periods of low rainfall or drought. Actual water needs depend on factors like soil type and species.
- Water perennials and vines well in the first growing season after planting. One rule of thumb is to water with a one-hour trickle at least once per week using a soaker hose for the first three weeks, barring a good rainfall, and subsequently during hot dry weather. Afterwards, perennials selected to match site conditions should need little or no supplemental watering. If you notice wilting or browning on your perennials, water to a depth of 10 to 20 cm (4 to 8 in.) to help restore the plant’s turgidity and vigour.
- Apply a layer of mulch about 5 to 7.5 cm (2 to 3 in.) deep over the soil surface of the garden to retain moisture, moderate soil temperature, control erosion and suppress weeds. Wood chips, bark and crushed rock are just a few of the materials that can be used as mulch.
- Use a soaker hose placed at the base of plants, rather than using a sprinkler. This will help to apply water to the soil and roots — rather than the leaves — and reduce evaporation.
- Grass under your tree competes with the tree’s roots for water. Remove the lawn and apply mulch instead which helps to retain water.
Designing a Water-Efficient Garden
You can create a lush, colourful garden, like the one in Figure 2, that requires little maintenance or water by applying the seven principles of xeriscaping — an approach to designing landscapes so that their water requirements correspond to local climatic conditions. While these are sound principals for any garden, they are particularly useful if you live in a region with low rainfall or that experiences water shortages.
Figure 2: Xeriscape design
1 — Design for your site and your needs
Sketch your lot including property lines, buildings, driveways and features that will remain. Add trees, shrub and flower beds, lawn areas, patios, decks, etc. (see Figure 3). Consider the specific conditions of your yard, taking into account that water requirements will differ in shady versus sunny spots, and slopes versus flat areas or depressions. Moisture availability for your plants will also differ according to your soil type. Sandy soils drain water whereas clay soils hold water. Some places, such as narrow side yards, may be hard to water.
2 — Group plants with similar water needs to make watering more efficient
Shrubs and perennials should be grouped together in mulched beds. Trees should also be clustered in mulched beds rather than isolating individual specimens in lawn areas. This will help to reduce moisture loss and competition.
3 — Amend the soil
First, find out what type of soil you have and improve its water retention capabilities accordingly, for example, by adding compost or other organic materials.
4 — Size your lawn area to meet your practical needs for play and traffic
Avoid many small or narrow lawn areas in favour of a consolidated lawn, to make them easier and more efficient to water. For primarily visual areas, consider water-efficient ground covers, perennials or shrubs. For foot-traffic routes or narrow spots, such as side yards, a permeable inert surface such as wood chips or natural stone requires no water.
5 — Choose plants that are well suited to your climate and site conditions
Consult your local garden centre or the references at the end of this article to find plant lists. Know your site including its soil types. In shady areas, use shade-tolerant species or consider a woodland shade garden. In sunny spots, use drought tolerant, sun-loving species or consider a wildflower meadow. Drought tolerant species should be used on rapidly-draining slopes (avoid turf grass), but you can consider moisture-loving plants in depressions or low spots. For a water-saving lawn, choose a species best suited to rainfall levels in your region. Low-maintenance lawn seed mixes are commercially available. Check your local seed companies or garden centre.
6 — Use mulch
7 — Use an efficient irrigation system and appropriate maintenance
Follow the tips listed in the previous sections.
Figure 3: Sample xeriscape with meadow and low-maintenance lawn
Other Outdoor Activities
Lawn and garden watering is not the only outdoor activity contributing to summer peak demand. You can lower your water bill and relieve the burden on municipal water supplies by doing the following:
- Use a broom instead of water to remove debris from paved surfaces such as driveways.
- Use a bucket and sponge to wash and rinse your car, instead of a hose.
- Cover swimming pools when they are not in use to reduce evaporation.