Planting Vegetables Over a Septic Leach Field

Can I plant a vegetable garden on my septic tank leach field?” – Eric

The septic tank leach field is a tempting spot for a vegetable garden – it’s large, flat, and usually sunny. However, it is generally not recommended to plant vegetables in this area, for several reasons:

There is a risk of contamination:

  • As septic tank effluent drains out into the lines, it is filtered slowly through the soil, and beneficial soil microbes digest harmful bacteria and viruses. That means that near the lines, there is some amount of contamination, and the extent depends on the type of soil, the rate of absorption, and the quality of the system. While septic systems are designed to prevent disease-causing soil contamination, there’s no easy way to know if your system is functioning properly.
  • In addition to bacteria, think about all the household chemicals that go down your drains every day. In general, plants help the environment by absorbing and processing chemicals – which could end up in your vegetables.
  • Root crops are more easily contaminated, and their roots can interfere with the drain lines.
  • Leafy vegetables can be contaminated by water splashing up from the soil surface.
  • Taller or fruiting plants (such as tomatoes, cucumbers) are less likely to be contaminated – problem is, there’s no way to tell what kinds of (or how much) bacteria is on them.
  • If you have a water-softener system, it will discharge brine (salt) into the system, which will harm salt-sensitive vegetables such as peppers and beans.

Also, the proper functioning of your septic system can be harmed by:

  • Raised beds that interfere with the evaporation of moisture.
  • Tilling, digging, and foot traffic, which can damage the septic lines.
  • Irrigation, which upsets the careful process of filtering and evaporation.

Instead of vegetables, plant your septic leach field with shallow-rooted, drought-tolerant ornamental plants, grasses, or ground covers. For more information, and plant suggestions check out:

  • Planting on your Septic Drain Field (Virginia Tech)
  • Planting on Septic Leach Fields (University of Nevada)

Julie

12 COMMENTS

  1. I have cucumbers planted close to my drain field but not over it. And the slope is such that surface water over the drain field would run away from the plants. So I am not too worried about them. But absolutely its not a good idea to plant veggies over the septic tank drain field.

  2. I am wondering how close to a mound septic system I can plant my vegetable garden, and still be safe from harmful contaminants. Would 10 feet from the base of the mound be sufficient distance?

  3. I have planted a garden on my mound system for years I also added at least a 6′ layer of organic dirt from an dairy and cattle farm nearby. I have never had any problems and harvest huge amounts of vegetables…if you do not use harmful chems in your house hold they will not be in you septic system and not contaminating your food. the garder covers the entire system top sides and below.

  4. I have a 20 by 50 foot garden which is sitting over a septic drain field…I added 6 inches of black dirt and get amazing vegetables…..I have never once had an issue….
    The drain tubes are 30 inches down and my only worry would be the roots of some plants…..but as far as contamination…never…..plant on…!

  5. I have one of these $25,000 alternative engineered septic systems where the leach fields are only 12 inches down. Supposedly the water comes out clear. Do you think it is safe to grow vegetables in this shallow dirt?

  6. My husband has been digging up tree roots along the edge of our septic mound. He was going to put it out in the pasture where new born kids will be. Is this dangerous to the goats, land, and wildlife?

  7. I see a lot of information about planting on or near leach fields. How long after a leach field is done being used can I plant vegetables safely? Does the leach field have to be dug up? Thanks.

  8. I was going to put raised beds 10 inches above septic bed 12 ft by 6 ft ( 2 beds ) If I put that black cloth down so roots don’t go any further will the beds harm septic system??

  9. I was thinking about doing a 20×20 carving pumpkin patch over the septic leach field. Would this be safe as it is not intended for consumption?

    • Hi, Shannon,
      Contamination may not be a concern since these pumpkins are not intended for consumption, but it’s also important to consider your drain pipes, which can clog easily.
      Here’s more information about that: https://www.drweil.com/health-wellness/balanced-living/gardening/is-it-dangerous-to-plant-on-a-septic-field/
      Good luck!

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