Sustainability is a word we hear often these days, in many contexts. But what exactly does it mean? In its broadest definition, it means practicing environmental stewardship so that we meet our present needs without compromising the ability of future generations to meet their needs. Sustainable practices can come into play in agriculture, energy use, combating global climate change, preservation of our oceans, resource and water use -- really, any way in which our human activities have an impact on the natural world around us.
While it's important to encourage sustainability on a large scale, we can also have an impact through the decisions and practices we adopt as individuals. One way to do this is to incorporate sustainable, ecologically sound practices into the gardening and landscaping we do around our homes. It may not have the global impact of government actions on greenhouse gas emissions, but it can make our own corner of the world a better space, both for ourselves in the present and others in years to come.
As with so much of gardening, a great place to begin is with the soil. Enriching your soil with organic matter will help it absorb water and drain well, resulting in better plant growth and less water run-off. Adding organic matter such as compost will support the many beneficial organisms that contribute to healthy, living soil that sustains plant growth with less added fertilizer. It also helps the soil lock up carbon that might otherwise go into the atmosphere. Growing a winter cover crop or summer green manure will not only add organic matter, but prevent the erosion and carbon loss that can occur when soil is left bare. Making compost from your garden and kitchen wastes keeps these materials out of landfills and completes the circle of recycling and renewal in your garden.
Think about the energy use that goes into your landscape, from the gas used to run a lawnmower to the energy required to manufacture, package, and ship synthetic fertilizers and pesticides. A gas-powered mower gives off smog-forming pollution and carbon dioxide. Reducing lawn size and using a push mower are two strategies for maintaining a more sustainable lawn.
An enormous amount of energy goes into the manufacture of synthetic fertilizers and pesticides; the production of herbicides with which so many lawns are regularly doused generates more carbon emissions than other kinds of pesticides. Using organic fertilizers, compost, and non-chemical pest and weed controls not only makes your landscape more climate-friendly, it makes it safer for you, your kids and pets, not to mention the birds and bees.
It's not just the growing parts of the landscape that can have an environmental impact. If you're buying wood lawn furniture, make sure it comes from non-threatened tree species by choosing products certified by the Forest Stewardship Council (FSC) and locally manufactured, if possible. Concrete manufacture is extremely energy-intensive; consider other materials for patios, walks, and drives.
Trees and shrubs are the backbone of a landscape design. But besides contributing to the visual appeal of our gardens, these plants contribute to its sustainability as well by removing both pollutants, like smog, and carbon from the atmosphere. One recent study showed that the urban trees of the U.S. (excluding Alaska and Hawaii) sequestered nearly 23 million tons of carbon each year!
Placed thoughtfully in the landscape, trees and shrubs can also reduce a home's energy use. Deciduous trees planted to shade the south side of a building reduce the energy needed for summer cooling, but allow winter sunshine in to add warmth when it's needed. Evergreens planted as windbreaks help decrease the energy needed to heat a building in winter.
It's important to choose plants that are suited to their site. Healthy, long-lived plants provide the greatest benefits, both aesthetically and environmentally. Start by doing an assessment of your soil and climate. Choose suitable native species where possible; they are likely to be well-adapted and be the most useful to wildlife as habitat and as a food source. Be sure to avoid any species that are invasive in your area. Check out our website for information on a wide variety of landscape plants. Your local Cooperative Extension Service, Master Gardeners program, or experienced garden center staff can also help you select the most suitable plants for your particular situation.
Conventional lawn care practices contribute an inordinate amount to the negative environmental impact of many landscapes. I've already mentioned the size of a lawn's carbon footprint, but energy use isn't the only downside. Water runoff that carries the nutrient phosphorus from lawn fertilizers reaches lakes, streams, and rivers, where it is a big contributor to algal blooms and the fish-harming depletion of oxygen they cause. Research has shown that a pound of phosphorus can fuel the growth of 300 to 500 pounds of algae in a body of water! Many lawn chemicals have also been linked to health risks to people, especially children, as well as pets and wildlife, and can pollute waterways. Irrigating lawns uses water resources that are becoming increasingly scarce in many areas.
Lawns are not all bad, of course. They, too, take up and store carbon, and allow rainwater to soak into the soil, rather than running off. And there is really no type of plant other than lawn grass that can take foot traffic and provide a spot for kids and pets to play. But in many landscapes, large swaths of lawn serve no practical purpose and might be replaced with more environmentally friendly plantings.
Where you do choose to grow a lawn, care for it sustainably. Mow the grass high to encourage deep rooting and shade out weeds. The best height depends on the kind of grass you're growing. Cut the cool-season grasses grown in the northern half of the country 3 inches high. The best mowing height for southern warm-season grasses depends on the particular grass you are growing. Check with your local Cooperative Extension Service for advice. Let the clippings remain on the lawn when you mow to recycle their nutrients back to the soil.
To make sure the fertilizer you put down helps your lawn, rather than running off to cause problems in the watershed, use one that has at least 50 percent of its nitrogen in organic or slow release (water-insoluble) form. Sweep up any fertilizer that lands on driveways and sidewalks as you spread it, and avoid fertilizing right before heavy rain is predicted.
Research has shown that, on established lawns growing on soils that did not test deficient in phosphorus, adding this potentially watershed-harmful nutrient in fertilizer did nothing to benefit the growth of the turf. So, for established lawns, test your soil every 3 to 5 years and, if the soil test does not show a phosphorus deficiency, use a fertilizer that does not include this nutrient. Look for one with a zero for the middle number in the analysis, for example 5-0-10 or 10-0-10. (That middle number indicates the percentage of phosphate in the fertilizer.) Even if the soil test shows a need for additional phosphorus, adding it in late fall does not benefit the grass and increases phosphorus in the runoff. So apply any phosphorus-containing fertilizers in spring or early fall. Phosphorus is helpful in the establishment of a new lawn the first year after sodding or seeding and does not contribute to runoff when it is applied to new lawns according to recommended rates.
Time your lawn fertilizing right to benefit your lawn the most and reduce the likelihood of polluted runoff. Cool-season grasses benefit the most from a main feeding in early fall, while warm season grasses are best given their main feeding in late spring.
Conserve water by irrigating only when needed. Water in the morning to reduce losses to evaporation and put down enough to soak the depth of the lawn's root system, but not so much that puddles form. Then wait until you see your footprints in the grass when you walk across it to rewater. This will encourage the roots of the grass plants to grow deep, and they'll be better able to withstand periods of heat and drought.
Rain water that runs off your property is not only water that will not be stored in the ground for your landscape plants to use; it is also water that can pick up pollutants and excess nutrients that end up in streams, rivers, and lakes. There is much you can do in your landscape to protect your watershed. Some things are simple, such as making sure that any gutter downspouts discharge on to lawns or gardens, not on to paved areas. More ambitious projects include building a rain garden, a planted depression to collect runoff and hold it so that it can soak into the soil. Or consider using permeable pavers, which let water go through, if you are putting in a patio or driveway.
For pollinating and beneficial insects, birds, butterflies, toads, and more, make your garden a welcoming sanctuary. Minimize your use of pesticides, even organic ones. Plant a wide variety of nectar, pollen, berry, and seed producing plants, with an emphasis on selections native to your area. Provide a source of water, such as a bird bath for feathered visitors. A shallow pool of water with some stones or piles of gravel on which insects can perch will help beneficials quench their thirst. Some insects, especially butterflies and some pollinator bees, prefer a mud puddle. Let a hose or faucet drip just a bit to form a damp, muddy sipping spot.
If you can, let a corner of your yard go "wild." Even a small undisturbed area will give beneficial insects a place to shelter and nest. Plant some evergreens near bird feeders to give birds cover from predators and a place to shelter from the weather.
Devote some space to edibles and you'll not only get delicious, fresh vegetables, herbs, and fruits to enjoy, you'll reduce your carbon footprint by not purchasing produce that's been shipped many miles to the supermarket. You may even find yourself saving gas as you make fewer trips to the market and more to your sustainable garden!