Gardening to Prevent Stormwater Pollution
Updated: Mar 31
There has recently been a large increase in the number of gardens people are growing in California. The weather has warmed, the days have gotten longer, and many people are spending more time at home. These factors have encouraged a large population, myself included, to put in a brand new garden with a variety of fruits and veggies.
Gardens can provide a wide range of benefits to our personal health as well as the health of the environment if managed properly. Sustainable gardens promote strong soils, absorb rain to decrease runoff, and prevent erosion, which are all factors in putting a stop to stormwater pollution. Here are five ways you can make your garden a pollution preventing space!
Tip #1: Cover the Ground
One of the most important steps in preventing stormwater pollution at all of our project sites is to cover bare soil. When there is no cover or vegetation on soil, rain carries it into waterways and storm drains. Gardens are no exception to this rule. Bare soil in gardens can wash away with irrigation and rain, leading to sedimentation and stormwater pollution. The areas of most concern for bare soil in gardens are the walkways. Walkways are often left unattended and have the potential to turn into a muddy mess. However, they can be covered with mulch, wood chips, or a low-maintenance ground cover with pavers such as the moss shown below. This eliminates any exposed soil and allows for water to soak into the ground rather than running off.
Now that the walkways are covered, what about the bare soil in between all the plants? These areas can be covered with mulch, garden fabric, or black plastic. This not only prevents erosion, but can also block unwanted weeds and hold in water, promoting plant growth!
Tip #2: Create a Pollution Perimeter
The next step we take at our job sites is to establish a perimeter. We often use best management practices (BMPs) like silt fence that prevents sediment from exiting the project site. Although a silt fence may not be the best option for around your garden, there are other perimeters that will perform just as well that require little to no maintenance. One of the best ways to create a perimeter is to build raised beds, similar to the ones shown below. These contain the soil at all times, eliminating any chance of erosion. They also hold in water after rain, reducing the amount you have to apply yourself.
If raised beds are not preferred, perimeter options for gardens that are on the ground include trellis covered with growing vines, bamboo, wood, or even metal fence. All of these will help to contain any soil that is moved from rain or wind and will also keep critters out of your produce!
Tip #3: Reduce Artificial Amendments
At our project sites, we sometimes see spilled chemicals or concrete that could pollute stormwater. Similar to chemicals and concrete, artificial fertilizers, pesticides, and herbicides have the potential to cause stormwater pollution. Although artificial amendments can be very helpful in gardens, they are often over applied. The excess product that is not taken up by the plant or absorbed into the soil can be washed away by rain and irrigation and end up in waterways and storm drains. These chemicals can cause problems such as altered pH of the waterway, algae blooms that decrease oxygen, and harm to native plant, fish, and wildlife species. Minimizing the use of these amendments can help to prevent unnecessary pollution.
There are many common kitchen items that can be used as alternatives to artificial additives. For example, crushed up eggshells at the base of the plant deters snails and slugs while also adding calcium to the soil. Used coffee grounds deters snails, cats, rabbits, and squirrels. Burying small pieces of banana peel prevents aphids and adds nutrients to the soil.
All of these are cost effective ways to reduce your trash, help your garden, avoid buying artificial amendments, and our personal favorite... PREVENT STORMWATER POLLUTION!
Tip #4: Terrace on a Slope
Sometimes it is impossible to find a perfectly flat area for a garden. If the area has a steep slope, there is a higher chance for runoff and erosion to occur. Irrigation and rain will travel faster downhill, gaining velocity and taking more soil with it. To prevent this, terracing your garden will create more flat areas, which increases water infiltration and decreases runoff.
Tip #5: Plant for the Winter
Most summer plants will die off when the weather starts to cool in the fall. Some gardeners will remove the summer crops and replace them with a winter garden including cabbage, broccoli, peas, cauliflower, and lettuce. These crops can withstand weather that doesn’t drop too far below 35°F and provide produce throughout the winter. However, if maintaining a winter garden is not in the books, it is still important to keep the soil covered. Winter rains could wash away topsoil, creating stormwater pollution.
Planting a low-maintenance winter cover crop, especially one that adds nutrients to the soil, can prevent erosion while also providing benefits to your next summer garden. Some examples include winter field peas, vetches, and crimson clover. Crimson clover, pictured below, has beautiful red tops and is ideal for soil that isn’t needed until early summer. It not only grows close together and covers bare ground, but also takes nitrogen from the air and fixes it into the soil for future plants to use as a natural fertilizer.
With all of the new gardens being planted, it is important to maintain them in a way that is sustainable. Covering the ground, creating a perimeter, minimizing artificial amendments, terracing gardens on slopes, and planting during the winter are all ways to prevent stormwater pollution in your own backyard. We hope this list gave you some ideas on how to manage your garden to grow lots of veggies and create a healthy environment.