Is a no dig vegetable garden safe with septic tank on property?

by Stephanie
(North Augusta, SC, USA)

Hello, I love the no dig vegetable garden idea! We have a septic tank/drain field in the front yard and I want to plant my garden in the backyard.
I have heard that pathogens and other types of diseases can contaminate fruits and vegetables when planting on property that has a septic tank system. Would the no dig garden option be safe for us?
I understand that the no dig garden is above ground but will it mix with our soil over time and be unsafe to continue to use. Any advise would be greatly appreciated. Thanks for your time!
-Steph

Comments for Is a no dig vegetable garden safe with septic tank on property?

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Apr 29, 2012

Growing vegetables near a septic tank NEW
by: ~ Megan

When I lived on our farm, we had the septic tank on the low hill near our house.
There was a long, sloping area about 15 metres downhill until flat land. On this flat land and partly to one side was our vegetable garden.
According to the plumber and all horticultural and other experts, there was no way any harmful bacteria or pathogens could contaminate the vegetables.

The soil was mostly sand, so it was perfect drainage and apparently the drainage went over a cone shaped area, widening further with distance, but deeper underground.

If there had been heavy metals, drugs or chemicals in the septic tank system, that could have been taken up by plants if they had been close to any drainage. There wasn't in this case.

Plants cannot absorb septic tank bacteria etc – it's complicated, but their roots can't.
There are millions of farmers and vegetable growers in India, Africa and worldwide that have for hundreds of years and still continue to use their own version of treated human sewerage to successfully and safely fertilize their gardens.

The problem of contamination comes if effluent touches leaves or parts of plants that are eaten. If there is likelihood of this, then these vegetables must be well washed. Simple commonsense. With larger commercial vegetable growers, this step can occasionally be lax, causing problems.

High industrial areas, and land previously contaminated with heavy metals are harder to grow vegetables safely in. In these cases, new soil/compost needs to be used. I remember a rose nursery I worked on in Nottingham, UK, had chromium poisoning. This caused chlorosis with yellowing between the leaf veins.

So back to the question: There are a lot of different points to consider, such as slope, soil type, distance and so on, but bacteria cannot contaminate plants from underground and anyway it sounds like there is plenty of distance between your tank and garden in case of possible chemicals.

If your soil is heavy bad draining clay, a plumber could advise you on an overflow pipe and possibly a sand seepage area near the tank if necessary.

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