The entire West Coast is experiencing longer, warmer dry seasons, with significantly less precipitation during the rainy season. The West is officially in a drought and regional governments are serious about outreach on the issue. California is suffering one of the worst droughts in our history, prompting Governor Brown to call for a 25-percent reduction in water use. Here in the Bay Area where I live, last summer we surpassed that mandate and successfully reduced water use by 30 percent.
One of the primary targets of reduction efforts has been water used in the garden. Homeowners are being asked to conserve water by letting their lawns die out; “Brown is the New Green” has become a catchy but simplistic slogan used by local municipalities.
But green is the color of nature.
The Movement of Water
As a garden designer and landscape contractor, I’ve have spent the past 25 years focusing on ecologically sound gardening and thoughtfully experimenting with ways to reduce water use in the garden while keeping it looking lush and beautiful.
It’s important to understand that green, growing things (plants) provide a critical role in supporting the earth’s water cycle. Reducing water use by allowing our gardens to dry out and brown will only escalate our drought problems.
Transpiration is the movement of water through plant leaves, stems, and flowers into the atmosphere where moisture condenses and contributes to precipitation that falls from the sky and back into the soil. And then the cycle repeats. Less rain means less access to naturally clean water. And in the absence of a thriving layer of plants, any water captured in the soil moves further down into the ground, where it can be stored for thousands of years. Without plant cover, transpiration is reduced, in effect robbing the water cycle of potential moisture. A loss of green plants will increasingly heat up the planet and dry it out.
With this in mind, responsible gardeners should look to nature as a guide when designing landscapes and managing water. Growing gardens—especially in urban areas—helps to cool the environment.
The water cycle is an amazing recycling system. Water is cleaned and purified when it passes through plant roots and soil. By encouraging the natural water cycle in our garden, we are developing a more effective response to drought conditions.
Capturing the Rain and Harvesting Greywater
Rainwater harvesting and installing greywater systems are two ideal ways we can keep our gardens green without using additional potable water. Directing water into swales or habitat depressions on the property, using permeable surfaces, and collecting rain from rooftops keeps water on site and available for plants. Contouring the land and switching from non-permeable surfaces, such as concrete, to surfaces like gravel and sand-set stone pavers that absorb water, accomplish this.
Greywater—water that has been used in your home—is considered safe to use in the garden as long as it is handled properly. Rerouting greywater from washing machines, bathroom sinks, and showers into the landscape instead of the city sewer is good for the garden and lessens the load on the municipal system.
There are several innovative ways to capture and use greywater. Washing machine water is the most accessible, and routing it to your garden is a simple DIY project that most homeowners can do. Online resources and irrigation vendors, such as The Urban Farmer in the Bay Area, provide information and instructions. Many public utilities have developed rainwater and greywater harvesting guidelines for consumers. San Francisco’s water and sewer utility has published a comprehensive instruction manual that will guide you through the process of building a greywater system of your own; you’ll find a link to that information in the resource box at the end of this article.
There are many ways of designing a greywater system for your garden, and they vary in complexity. Applying water from your washing machine directly at the base of well-mulched fruit trees is the simplest use of greywater in the home landscape.
A more complex action is to filter greywater through a constructed wetland where soil and plant roots clean the water like they would in nature. At Mariposa, we call this a Living Fountain. Once plant roots and soil have cleaned it, water is routed through a drip irrigation system in your garden. Furthermore, the living fountain bio-invigorates water by removing soap, salts, and other chemicals that we do not want in our gardens, while adding beneficial and life-giving microbes and bacteria that improve the health of your plants. The result is plants that are healthier and more resistant to pests, disease, and drought.
It is important to build life both in and above the soil. A living fountain benefits the overall health of your garden by supporting a diverse plant palette in the garden, including those that thrive in wet conditions. In turn, plant diversity attracts a more diverse array of beneficial insects and contributes to the development of an ecosystem that helps control pests and diseases.
There are many ways to re-think the way we treat and use water. As our climate continues to warm, I encourage all gardeners to learn more and to start using water recycling practices in the garden. There are many non-profit agencies and for-profit businesses that are ready to help you.
Yes, it’s time to reduce how much water we use. But it will never be time to further dry out our planet. Let’s not throw the baby out with the bathwater, so to speak. By finding a way to collect and recycle water, we’re on the path to balancing the water cycle, one garden at a time.
Mariposa Gardening & Design is an award-winning design-build landscaping company with a strong commitment to creating beautiful, ecologically minded gardens. Founder Andrea Hurd and her team promote water conservation with their innovative approach to replicating natural systems.
DIG Cooperative, Inc. is a design-build general contracting firm specializing in comprehensive, on-site water catchment and reuse systems for residential, commercial, and institutional clients. Their team is committed to harnessing the power of water to transform urban environments into resilient habitats with regenerative ecology, quality craftsmanship, and creative collaboration.
Together, Mariposa Gardening and DIG Co-op design and install landscape irrigation systems for meadows and drought tolerant eco-landscapes.
The Urban Farmer Store is located in San Francisco, Mill Valley, and Richmond Annex. Check out their online library of resources, including information on greywater and rainwater harvesting.
Greywater Action is a collaborative of educators who teach residents and tradespeople about affordable and simple household water systems that dramatically reduce water use and foster sustainable cultures of water. On a policy level, they work with water districts to develop codes and incentives for greywater, rainwater harvesting, and composting toilets.
Access the Graywater Design Manual and other valuable information from San Francisco Water Power Sewer at www.sfwater.org, search: Graywater.