Gardening For Better Water: How Gardening Affects Water Supply

Most gardeners aren’t aware of how gardening affects our water supply. Learn how this happens, and how you might improve your gardening practices for better water conservation.

A watering can waters plants
(Image credit: Imgorthand / Getty Images)

Most of us are aware that many of the planet's environmental problems are caused by human activities on the land. This is a matter every gardener should consider - how can we change our habits in the landscape to avoid polluting our environment? Each individual can make a positive impact by following sustainable gardening practices.

Are you wondering how gardening affects the water supply? Read on for information on making water conservation a goal in gardening.

How Do Gardening Practices Impact Our Water?

Water is found in our atmosphere, in snow and ice, in ponds, lakes and oceans, but also in plants and animals and soil. There is a cycle to water: it rains down from the sky, soaks into or runs off the soil into nearby lakes or rivers.

That means that all of our gardening practices can impact the global water supply. While it’s easy to think that the garden water you use in one backyard will not have much of an effect, it all adds up. The cumulative effect of everyone’s actions becomes significant. Each of us must acknowledge that our activities can present a risk to the environment.

Can Plant & Lawn Fertilizers Pollute Water Supply?

The water cycle is a very delicate system, and how we manage our landscape has a dramatic effect on that system. Since rainwater or water for irrigation flows through your garden, it will carry both yard waste and chemicals like excess fertilizer and pesticides. If the water soaks into the soil, those chemicals can mix with the groundwater that is used in the future in the garden. When the water runs off the landscape, these toxins can contaminate nearby coastal waters or rivers and streams.

Think about fertilizing your backyard. While some fertilizer goes into the soil, some may land on the driveway and be washed away. The same thing may happen in the yard’s of your neighbors up and down the street. All of that excess fertilizer flows into a small stream that joins a larger one and ends up in the ocean. A septic system that’s not properly maintained can also add to the groundwater flow.

An important step is to determine only use the fertilizer your plants require in your landscape. If you aren’t sure what you need, get your soil tested. Repeat the testing every few years. You will also want to avoid applying the fertilizer right before a rainfall. It is best to use a slow-release fertilizer rather than a fast-release product, since the latter is potentially the most damaging.

How Garden Polluters Impact the Environment

Other types of polluters can also impact the pollution of our environment. The equipment we use to care for our lawns, like gas-operated lawnmowers and leaf-blowers are good examples. We may not think of these machines as climate priorities but they are in fact a major pollution source, causing air pollution, climate change and health issues.

The 2020 Environmental Protection Agency’s report on emissions finds that lawn equipment releases as much smog-forming nitrous oxide as that released by 30 million vehicles. It also releases 30 million tons annually of climate-warming carbon dioxide. This is more than the total air emissions released by Los Angeles.

How Improper Lawn Mowing Impacts Water Quality

So it’s easy to see how our garden chemicals can impact the quality of water. But did you know that cutting your lawn can also significantly deteriorate our water supplies? If you handle lawn clippings carelessly, you can introduce nutrients into the water source. Yes, they are only grass clippings but they act as a slow-release fertilizer.

The leaf blades and stems contain within themselves all the nutrients needed for plant growth. On average, they contain 4% nitrogen, 0.5 to 1% phosphorus, and 1 to 2 % potassium by weight. Both nitrogen and phosphorus are problematic since they can cause eutrophication of water sources, causing prolific algal blooms that use up the oxygen in the water. Because of this eutrophication, many native plants and animals die off.

Best Ways to Reduce Water Consumption

Practices such as mulching and collecting rainwater are good ways to use less water in your garden. I think of mulch as a blanket of protection you place on the soil surface. It helps regulate the soil temperature, cooling the roots in summer and warming them in winter. It also reduces your water usage by limiting water evaporation from the soil and preventing weed growth that can hog the available rainwater.

You can also reduce your garden water use by using drip irrigation for your garden. This type of irrigation system only allows slow, controlled release of water to the soil through holes in a pipe or hose stretched along a row of plants. The water drops out slowly from the holes and is immediately absorbed into the soil. Using a drip irrigation system reduces your water loss by up to 60 percent over traditional watering methods.

Many homeowners are opting against traditional turf lawns to reduce their water consumption. But it’s more than just getting an efficient lawn watering system. If you still want a traditional lawn, take care in selecting the type of turf you plant, since water usage varies considerably among the turfgrasses. For example, pick buffalo-grass, one of the common turfgrasses that requires the least amount of water, over tall fescue, which requires the most water.

Drought-Resistant Plants To Help Conserve Water Supply

Building a garden from drought-tolerant or drought-resistant plants is known as xeriscaping. This helps to conserve water since the plants are either able to make do with available rainwater once they are mature, or else they require only occasional irrigation.

Why do these plants require less water? They are often native plants that have developed special characteristics that allow them to do with less water. They may have deep root systems that allow them to dig deep for soil in the water, or smaller leaves for reduced evaporation. Some have leaves protected by tiny hair or a wax-coating, which also limit evaporation.

To that end, consider these five drought-resistant superstars:

  • Purple fountain grass (Pennisetum setaceum Rubrum)
  • Kangaroo paw (Anigozanthos flavidus)
  • Lavender (Lavandula angustifolia)
  • Palo verde (Parkinsonia florida)
  • California lilac (Ceanothus spp)

Frequently Asked Questions

Can Plants Help to Improve Local Water Quality?

Yes, the appropriate choice of plants can help reduce water consumption and improve local water quality. Native plants require less water and virtually no chemicals to grow.

Teo Spengler
Writer

Teo Spengler has been gardening for 30 years. She is a docent at the San Francisco Botanical Garden. Her passion is trees, 250 of which she has planted on her land in France.