Building and Using a Precast Septic-Tank Root Cellar

Reader Contribution by Garth And Edmund Brown
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by AdobeStock/martinfredy

How does a precast concrete septic-tank root cellar hold up to a harsh New York winter? See how this DIY root cellar performs when temperatures drop.

I mentioned building a root cellar as part of my plans to source a year’s worth of food locally, but I thought readers of Mother Earth News would be interested in a more detailed description of making and using it. I based the design on these plans for an underground root cellar, which involves modifying an (unused!) precast septic tank. When I decided to join my brother Ed in growing all my own food for 2015, I knew I would need a better place to store our root vegetables than the old farmhouse basement, but using using cinder blocks or building forms to pour concrete in place seemed like a bigger job than I had time for. Using a precast 6-foot x 6-foot x 10-foot tank and some materials I had on hand made the job much easier than it would have been, and I ended up with a root cellar that has maintained a stable temperature and high humidity even in the worst of a harsh New York winter.

One of the biggest potential jobs required to put in a cellar, no matter the design, is digging the hole. Luckily, I already needed to rent an excavator for some other things around the farm, and it made what would have been days or weeks of work with a shovel a matter of a few hours. The location I chose is a bank off of the driveway. It’s south facing, which concerned me a little — I thought it might be prone to overheating — but it was the only suitable site within a reasonable distance of both the houses and the garden.

There were a few tense minutes when it looked like the truck that was delivering the septic tank would not have room to maneuver into position, but the driver finally managed to line it up. I’d been expecting a boom truck, which can drop a tank almost anywhere, but at the last minute I got a call from the concrete company saying the tank weighed so much that only their truck with a slide off of the back could handle it. It ended up working out, but it would have been less stressful if that miscommunication could have been avoided.

  • Updated on Apr 4, 2023
  • Originally Published on Mar 4, 2015
Tagged with: food preservation, Garth and Edmund Brown, New York, Reader Contributions, root cellar
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