Can I Garden over my Septic System?

As we start to think about gardening and lawn care this year, one question may pop up: Can I garden on my septic system? Well, there are a couple of questions to consider:

  1. Can a garden be contaminated by bacterial and viral hazards which may be found in septic drainfields? A properly operating septic system will not contaminate the soil with disease organisms, but it can be difficult to tell if the system is working at optimum efficiency.  Also, the soil type can make a difference. Clay like soil will eliminate any organism within a few inches of the system, while a sandy soil could allow for movement of bacteria several feet.

Since it is hard to be sure if your septic system is working an optimum level, I do not recommend planting a garden in this area. An ornamental, such as grass, would be a better fit for this area. But, I know many of you will still attempt to raise a garden in this area anyway.  So if you do, stay away from rooting crops such as carrots or potatoes. Also avoid leafy vegetables such as lettuce or kale, since water may splash up from the ground during rains. Plants that grow up off the ground, such as tomatoes, may be a better fit. Be sure to trellis any vining crops, such beans or squash up off the ground.

  1. Is it safe for the septic system to have a garden growing over it? The simple answer is no. While walking or light digging over a drain field is not a problem, plowing, tilling, or building up soil for a raised bed can damage the system. According to Marvin Dixon at the Madison County Health Department, gardening on a septic system can damage components and lead to erosion in that area. He recommends gardening no closer than ten feet from the drainfield.

 With all of that in mind, stay at least ten feet from the septic system. The health of you and your family is too important to be put at risk and the cost to repair a septic system is too high to chance it.

Submitted by Amanda Sears, Agent for Horticulture, Madison Co. Cooperative Extension Service