Dear Alison,

Thanks for submitting your question about growing vegetables in raised beds over your leach field. My name is Deborah Hoover and I serve as a volunteer for Infoline through the NH Master Gardener Program.

In general, growing vegetables over a leach field is not recommended due to the risk of contamination of your crop, especially root vegetables. Deep roots over a leach field are also a threat to the structure and function of the septic system. While some sources suggest installation of a barrier under a raised bed on a leach field, this approach interferes with a septic system's need to breathe in order to serve its purpose.

With caution, gardeners can plant flowers and grasses that have shallow roots on a leach field.

For more information on planting gardens on a leach field, please refer to this informative publication from UNH Extension, including a list of flowers to consider:

https://extension.unh.edu/blog/2019/12/it-okay-plant-garden-over-leach-field

And here is another helpful publication from The University of Maine Extension: Vegetable Gardens and Septic Fields Don't Mix.

https://extension.umaine.edu/publications/2442e/

I wish I could be more encouraging, and I do hope you will find another good spot for growing vegetables.

Kind regards,

Deb Hoover

NH Master Gardener