Water Wise Gardening: Using Less Water
Updated: Apr 27, 2022
So far we have talked about capturing and storing water in our landscapes. Now it is time to talk about making that water go further by using less of it. Today we will look at our number one water user: our lawns, and we will see how we can reduce our water usage by adjusting how (and when) we water our landscapes. Lastly, we will review the seven principles of xeriscaping, or dryland landscaping. Surprise! We've really been talking about xeriscaping all along.
Lawn: the number one water user
I don't think it's news to anyone out there that lawns are the largest users of water, fertilizer and human effort in the garden landscape. Most of the grass species we have in our lawns here are meant to go dormant in the heat and drought of mid summer, just like our native grasses do. That is how cool season grasses handle drought and heat stress. It takes and enormous amount of energy and resources to prevent this natural process from occurring. Keeping a pristine, lush, vibrant green lawn all summer long will cost you. Am I saying you need to get rid of all your current lawn? Absolutely not! However, there are some strategies we can use for reducing the water needed on this space.
Reduce your lawn area
Do your really need a massive expanse of lawn? What do you actually use it for? If you need a large space for kids to run around and for impromptu games of flag football, then a significant expanse of turf grass may be exactly what you need. However, many people have grass purely for aesthetic purposes. It is neat and tidy and fits well into neighbourhoods full of lawns. You know what else is beautiful? Yards filled with lush plantings of trees, shrubs and perennials. They are full of colour and texture. They are full of life: birds, butterflies and bumblebees! They change throughout the seasons and give winter interest no lawn could ever provide. They can supply us not only with beauty and habitat for wildlife, but also food. So much food potential!
You don't need to convert your entire yard. Start small. Add a border or mixed bed to your landscape. Once you have the hang of it, expand it just a bit. Before you know it, you will be digging up lawn and adding a cornucopia of vegetation. And if you plant species that are hardy and appropriate for you area, you will dramatically reduce your yard maintenance workload, and your water use at the same time.
If you are going to have some lawn area, there are some strategies to significantly reduce the water needed on that space.
Set the blade of your mower higher. Shoot for a grass height of 2-3". Longer grass means less evaporation, which means less watering for you.
Use a mulching lawn mower. This puts finely chopped grass clippings back onto your lawn, which quickly break down and act as nitrogen rich compost or fertilizer. Plus no work bagging and disposing of organic material. Win-win.
Think about the shape of your lawn area. Odd shapes are going to mean moving your sprinkler around multiple times to cover every inch, resulting in wasted time and water. Rectangular or circular shapes that mimic the coverage of whatever sprinkler you use will be the most efficient.
Think about a lawn alternative
Green spaces don't have to be Kentucky Blue Grass! Fortunately, there are many seed companies that realize customers want options. For example, West Coast Seeds has five different lawn options, some that stand up to wear and tear, some that are great for pollinators and some that help rejuvenate poor soil by fixing nitrogen. Micro clover is one very popular choice. It can be walked and played on, supplies pollen and nectar to bees and butterflies, and fertilizes the soil naturally (it's a nitrogen fixer). Micro clover is also compact and dense (crowding out weeds) making it very tidy looking, similar to turf grass for those who want a comparable look. You also do not need to dig up and replace your entire lawn to make a difference. Many lawn alternatives can be over seeded on your existing lawn and allowed to spread and slowly out compete your existing turf.
The less water we allow to evaporate from the soil into the air, the more moisture will be available for our plants. Makes sense right? We can reduce evaporation by protecting the soil from the hot sun and from drying winds. That can make a big difference in a windy climate like ours! Provide shelter using wind breaks consisting of trees, shrubs and fences to block areas where wind whips through your site. Some good observation will help you determine the best location. The second way to reduce evaporation is to ensure all your soil surfaces are covered. This can be with either vegetation or mulch. Plant densely (ensuring there is still space for plants to reach full size) and fill all those in-between spots with mulch. This will prevent moisture from escaping off the surface of the soil, will keep the soil cooler, reduce erosion and will reduce weed growth. We don't want weeds stealing the moisture intended for our purposefully planted guys!
If you use a bark or leaf mulch around your plants you will also improve the soil as it slowly breaks down. That's good organic matter right there! Increasing the organic matter in your soil, whether from the decomposition of mulch or from added compost and manure, will increase your soil's water holding capacity. Not only will your soil hold and retain more water, it will also soak in faster, reducing the puddling that many of us with clay soils have experienced.
Reducing compaction as much as possible in your plant beds is another way to improve your soil. Repeatedly walking on or rototilling your soil wrecks its tilth and texture. We want light soil with diverse soil aggregates (different sized clumps) and lots of soil life! Healthy soil should have lots of different sized pockets between all those aggregates. These pockets hold both water and air (we look for around a 50% mix of each). Our plant roots need both water and oxygen to grow well! The more soil pockets, the more water you soil will be able to hold, and the healthier your soil too. And don't forget to keep up with your weeding. Save the water for the plants you actually want to grow.
No matter how much planning you do and how drought resistant your garden is, there will be times when you do need to water. All trees, shrubs and perennials will require water for at least their first year of growth while they are getting their roots established, no matter how drought tolerant they are. This also includes anything you dig up and divide or transplant as well. Annuals often require even more moisture, and those in containers will often need watering every single day, even twice a day in really hot weather.
Traditional lawns require approximately 1" of water per week when it is 20 C outside. They require 1.5" to 2" once the temperature reaches 30 C. If it is windy, lawns will need even more water.
Some watering is inevitable, but there are a number of things we can do to reduce the amount of water we use and make it that irrigation as efficient as possible.
When to water
The best time to water is definitely in the morning. This is the time of day when we have the least amount of evaporation. Morning is also a non-peak time for water use in most cities, which means less strain on local utilities. In addition, watering in the morning allows moisture on plant foliage to evaporate quickly, resulting in less fungal and mildew issues. Conversely, if we water in the evening, that moisture is retained on leaves and stems for much longer periods and at cooler temperatures; the perfect conditions for mold, mildew and fungus. Watering deeply and less often encourages deep roots that are more able to survive drought. Trees and shrubs appreciate water delivered deep down where their roots are. Remember to check your hoses and sprinklers regularly for leaks and blockages.
Sprinkler selection and use
When using a sprinkler to water your landscape there are a number of things to keep in mind:
Ensure the spray goes only where you need it: on your plants and soil. Your driveway does not need watering!! (Sorry for shouting but I see this all the time and it drives me bonkers.) Having a sprinkler with a spray pattern that matches the shape of the space to be watered will make your life easier and save money on your water bill.
You also want to ensure the sprinkler is delivering water at an appropriate rate. Too much too fast will mean your soil cannot absorb the water quickly enough. Instead, the water will run off the surface and into the storm sewer, eroding the soil as it does. That's just a waste. Select a sprinkler where you can vary the water intensity and still have it work properly.
Sprinklers that spray water high into the air or into a very fine mist can be extremely inefficient. Fine water particles evaporate quickly in the sun and get blown by the wind to areas you don't necessarily need water. Often, very little water actually makes it to your plant roots.
Ensure you don't over water either. Automatic timers can work well to prevent this. You can also place an overturned frisbee on your watering area to measure out approximately 1" of water.
If you have an automatic watering system, such as underground sprinklers, you can save a significant amount of money on your water bill by installing water sensors. That way you are not watering in the middle of a rainstorm, or when the ground is already well saturated.
Various sprinkler options (L to R: impact, fan and contour). Photos by Lee Valley
This is the most efficient of all water delivery methods. Because the water is released directly onto the soil there is little to no water lost to evaporation and wind drift. They are close to 100% efficient. You can use long hoses to provide drip irrigation to whole beds (soaker hoses), or you can use spikes to water individual plants or pots. Water goes exactly where it is needed. Often, gardeners position their drip irrigation under the mulch (but still on top of the soil). This way you have even less evaporation from the top of the soil. Drip irrigation systems can easily be hooked up to automatic timers. There are even drip irrigation systems specifically for low pressure set ups, such as from rain barrels. There are a number of irrigation companies (Lee Valley too), that can help you set up a system that is right for your space. Fan sprinklers and impact sprinklers are the least efficient, as they shoot very fine particles high up into the air or over long distances (see images above).
It's time to talk about the poster child of drought tolerant gardens: xeriscaping. Many people think xeriscaping is just mulching with lots of rocks and planting cactuses and other succulents. Lets correct that image, shall we? Your yard does not have to look like the Mohave Desert to follow xeriscaping. Lets look at the seven principles of xeriscaping, one by one. Note that we have covered (or will cover in the next water wise gardening article) all of these.
1. Design your site with water availability and location in mind
We talked about this in the first article on water wise gardening. Think about water right from the beginning design stage. Locate things that will need lots of water close to your water sources. For example, make sure your annual veggie beds are close to a hose bib or rain barrel. Think about capturing and saving water at the initial planning stages.
2. Group plants with similar water needs together
Have some plants with high water needs? Put them together so you only need to intensively water one small area. Realistically, if you have both high water and drought tolerant plants scattered all together, you will end up wasting water on drought tolerant plants that really don't need it in order to keep the water loving plants from drooping. Not very efficient.
3. Amend the soil
We mentioned this in detail above. Adding compost, manure and decomposable mulch to your garden beds will increase the health of your soils and boost your soil's water holding capacity.
4. Size your lawn for practical needs. Consider alternatives where you can.
Do you need a football field sized lawn of Kentucky Bluegrass? Could you decrease the size of that lawn? What about lawn alternatives like clover?
5. Choose appropriate plants for your site and climate
We are going to go into detail on this in our next article. To sum it up, plants that are suited to a zone 3 drought prone garden will fare much better, be healthier and require fall less inputs (such as supplementary watering) in the Calgary area than plants that are not. Every plant has its ideal location to thrive. Let's find the ones whose ideal location is your yard!
6. Use mulch
There are a million reasons to use mulch in your garden: less evaporation, less soil erosion, adds organic matter to the soil, regulates soil temperature, reduces weeds, promotes beneficial fungal ecosystems, home for a ton of soil life, plus it looks good too! Just do it!
7. Use efficient irrigation
Like we mentioned above, choose a system with minimal water loss to evaporation and wind drift. Water only as much as you need. Use rainwater whenever possible. And please, for the love of gardening, don't water sidewalks and roads!
That's it for reducing water use in our landscapes. Hopefully you found some good ideas in here. You do not have to overhaul your entire site to make a difference. Even small things can add up, especially if many people are doing those small things. Our next article is the fun stuff! We will look at the strategies drought tolerant plants use to survive low water levels. Then we will look at all the trees, shrubs, perennials and annuals that are drought tolerant and appropriate for the Calgary area. With lots of pretty pictures too!
Yummy gardening everyone!
Other Articles In This Series
Water Wise Gardening: Capturing and Saving Water
Water Wise Gardening: The Right Plants
References and Further Reading
Lee Valley Tools (https://www.leevalley.com/en-ca) for water timers, drip irrigation systems, sensors, and other watering tools.
Regency Irrigation (https://regencyirrigation.com) for all your irrigation supplies.
Black Swallow Living Soils (https://blackswallowsoil.com/products/blumat-irrigation) for Blumat irrigation supplies (great for pressured, pump or gravity fed irrigation systems).
Burnco Landscape Supplies (https://www.burncolandscape.com) for perforated pavers, compost, mulch and other bulk landscape supplies.
West Coast Seeds (www.westcoastseeds.com) for lawn alternative seeds and other gardening accessories.
Veseys Seeds (https://www.veseys.com/ca/) for clover seeds and other gardening accessories.
T & T Seeds (https://ttseeds.com/) for clover seeds and other gardening accessories.
The Plantium (https://theplantium.com/2017/06/13/xeriscape-a-to-x) for a great in-depth article on xeriscaping.