With the gardening season just around the corner, many home gardeners are gearing up to plant this year’s crops. Looking around their yards, many homeowners wonder whether they can plant a garden over their septic drainfield. After all, it’s a wide-open space that often gets full sun throughout the day. But unfortunately, as tempting as it may be, gardening over your septic drainfield is not a good idea. In fact, septic owners need to be pretty careful about what they plant over the drainfield, gardening aside. Read on to discover the reasons gardening over a drainfield is not recommended and to discover what can—and can’t—be planted safely instead.
Gardening Over the Drainfield
We understand the appeal of transforming the lawn above your drainfield into a lush garden, but unfortunately, growing food over the drainfield is never a good idea for a handful of reasons. While a properly functioning septic system won’t necessarily contaminate the crops grown above the drainfield, there is no way to guarantee the soil (and your garden) is not contaminated. Unfortunately, with septic systems—even properly maintained septic systems—you don’t know there’s a problem until you know there’s a problem. Something breaks or malfunctions, and you don’t really notice until wastewater is backing up into your house or the drainfield is saturated with effluent. You don’t want illness from eating contaminated produce to be your signal that your septic system isn’t functioning correctly.
In addition to the potential contamination from pathogens, crops grown above your drainfield may also be exposed to household chemicals that are still present in effluent before it filters through the drainfield. Many of these are not safe for your septic system, let alone safe for human consumption.
What About Raised Beds?
Many septic owners who are itching to convert their drainfield area into gardens look to install raised beds over the drainfield. After all, this solves the problem of potential soil contamination from pathogens or household chemicals. Unfortunately, this is also not a recommended option. The added soil depth of raised garden beds can inhibit evaporation and limit the effectiveness of your septic system.
The Problems with Landscaping Over the Drainfield
In general, septic owners need to be very careful about what they plant over and near the drainfield. Depending on your system’s specific requirements, the drainfield pipes can be anywhere from 18 to 36 inches below the surface. Plants with woody root structures (most trees and shrubs) tend to grow much deeper than this. Their roots can invade, clog, and even dislodge the pipes in your drainfield. Generally, trees and shrubs that do not die back to the ground in the winter tend to have root structures that will damage your drainfield. Plants with these deeper root structures should be planted at least as far away as their estimated root spread at maturity. Ideally, they’d be planted much further away, as their roots tend to seek out and grow in the direction of water sources, which includes your drainfield.
In addition to paying attention to the root structure of the plants above and near the drainfield, septic owners also need to consider the water needs of landscaped plants. Plants the require frequent watering may saturate the drainfield and interfere with effluent evaporation. This is the main reason we recommend any landscaping around the septic system feature only plants native to Northeast Ohio whenever possible. Because native plants have evolved in our climate, they require less intervention (extra watering, chemical treatments, etc.) that may interfere with your septic system.
What Can You Plant Over the Drainfield?
Here’s the good news: landscaping with certain types of plants over your drainfield is safe and can actually help your septic system. Shallow-rooted plants, like perennials and some grasses, remove excess moisture and nutrients from the soil (especially phosphate and nitrate, both of which are commonly found in effluent and which contribute to algae growth in freshwater bodies). Their shallow roots also hold the soil in place during heavy rains, which helps guard against erosion. Turf grasses are the standard choice. Be careful not to plant tall grasses above your drainfield, as these have exceptionally deep and invasive roots. Perennials, annuals, and groundcover can safely be planted above your drainfield.
Supeck Septic is Your Trusted Service Provider!
When it comes time to service your septic system, you can rely on Supeck Septic to deliver exceptional customer service as we perform routine or emergency septic care. We are Northeast Ohio’s largest septic provider and are licensed, bonded, and insured for your safety. Contact us today to schedule your next service visit!