Growing Over Septic Tanks: Choosing Plants To Grow On A Septic System

(Image credit: Anne Webber)

last updated 3 February 2021

Septic drain fields pose a difficult landscaping question. They often cover a large area of land that would look strange uncultivated. On a shady piece of property, it might be the only sunny patch available. In a dry climate, it might be the only moist patch. On the other hand, not just anything is safe to grow on a septic drain field. Keep reading to learn more about picking suitable plants for septic systems.

Growing Over Septic Tanks

What is a septic drain field? Basically, it’s an alternative to sewer systems, usually found on rural properties. A septic tank separates solid waste from liquid. This liquid waste is sent through long, wide, perforated pipes buried underground. The wastewater is released gradually into the soil where it is broken down and sanitized by microbes before it eventually reaches the water table. Planting on a septic drain field is a good idea because it helps prevent soil erosion and reduces foot traffic, which can compact the soil and cause problems. Choosing the right plants to grow on a septic system is essential, though.

Septic Field Plant Choices

Opinions differ on whether it’s safe to grow vegetables on a septic field. No matter what, root vegetables should be avoided, and mulch should be put down to prevent wastewater from splashing up on leaves and fruit. Really, if you have anywhere else to plant your vegetables, it’s better to do it there. Flowers and grasses are a better choice. Suitable plants for septic systems have shallow roots, since the perforated pipes tend to be about 6 inches (15 cm.) below ground. They do tend to be spaced about 10 feet (3 m.) apart, so if you know their exact location, you have a little more leeway. Either way, choose plants that require little maintenance and no yearly division – this will help reduce foot traffic. Some good septic field plant choices include:

When planting on a septic drain field, keep digging to a minimum and always wear gloves.

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The only child of a horticulturist and an English teacher, Liz Baessler was destined to become a gardening editor. She has been with Gardening Know how since 2015, and a Senior Editor since 2020. She holds a BA in English from Brandeis University and an MA in English from the University of Geneva, Switzerland. After years of gardening in containers and community garden plots, she finally has a backyard of her own, which she is systematically filling with vegetables and flowers.