We’ve been working on this project for about a month now, now I’m sharing with you instructions on how to build a root cellar under a garden house or shed. I’m sharing our step-by-step guide to building a root cellar, as we build ours!
Why Root Cellars Are Perfect
I’m a firm believer that if you are prepared, you will not fear, no matter what happens in life. I’ve been taught my whole life to live frugally, grow a garden, preserve the harvest, save for a rainy day, and live as self-reliant as possible. (Matthew chapter 24) (Pharos Dream)
Root cellars are the ultimate for food storage… 100 years ago they put root cellars (or basements that can be used as a root cellar) under almost all farmhouses. I think canning became so popular that people didn’t feel like they needed a root cellar anymore, or somehow along the line root cellar building fell out of practice.
Root cellars are the ideal place for food storage to store fresh garden produce for months without any processing! Being underground keeps root cellars very cool in the summer months and cold but not freezing in the winter. Hence, you get the perfect temperatures with no electric costs.
It’s also very dark in a good root cellar. Dark areas with no sunlight prevent the growth and decay of root vegetables, winter squash, onions garlic, apples, cabbages, and other food storage.
Plus the humidity level in a root cellar is perfect for fresh produce and food storage. Traditional root cellars do not have concrete floors, they use rocks or just left them dirt floors. This earthy floor lets in just the right amount of humidity for keeping potatoes, and other produce in good condition for long periods of time!
First Choose A Root Cellar Location
I fell in love with root cellars after watching Shea Elliot’s root cellar tours on youtube. The problem was… Our water table was too high to build a root cellar under our house (the ideal location in my mind!) My husband was completely against a root cellar under the house… He’s been involved in disaster clean-up companies that had to dry up flooded basements and resulting mold.
However, I was already planning on building a garden house for potting plants and keeping tools, and a shallow root cellar under that would pose no threat to our home! So it was decided… A root cellar under the garden house was the ticket!
Anyone with room for a shed in their yard can build a root cellar under it! You do not need much land, just a small yard works! Our garden house is 12 feet by 16 feet, but you can do any size!
I chose a spot that wouldn’t get much water from neighboring properties or my sprinkler system.
Second – Excavate for Root Cellar
We hired Gary with Wiese Excavating out of Parma Idaho to excavate our root cellar spot. He was great at letting us know how deep we could go. Because our water table is so high (our well is only 26 feet deep.) we only excavated 6 feet down.
Remember excavators will need to dig a hole a few feet wider on each side so the concrete guys can get in there to work and lay forms. Our excavator dug 2 to 3 feet wider on each side.
Third – Pour Concrete Footers
After excavating, you’ll need to pour concrete footings for the concrete walls of your root cellar. These footers will bear the weight of the concrete walls and garden house or shed above, so they should be thick with rebar to strengthen them.
Our footers are poured about 1 foot thick and 18 inches wide with 2 rebar rods running in the entire footer, and rebar extending up to help support the walls that will be poured on top!
Fill in Root Cellar Floors With Rocks (If using)
We are filling in the dirt floor area of our root cellar with 4 inches of washed rocks. You can also leave this dirt if desired.
Fourth – Pour Concrete Walls
We are using Jarden with substratum concrete for all our concrete work…. This is way too much concrete to buy bags and DIY (unless you are way cooler than we are!)
Our concrete walls will be poured 5 and a half feet tall on top of the 1-foot footers already in place. These walls will be 8 inches thick with rebar throughout to strengthen them.
And those walls have rebar come up through the top every couple of feet, to screw the base plate of the shed above onto.
Fifth – Backfill
After the walls are poured and cured, we backfill the excess areas open around the foundation. We are having our excavator do this, it’s a lot of dirt to move!
After backfilling you will be able to lay your floorboards or I-joists on top of the concrete walls, to support the garden shed floor.
The root cellar sat through the summer as we were finished building the farmhouse. And I’m super glad we waited to build the garden shed above… Because we discovered a problem! It would start filling with water!
If Water Table Is Too High, Instal French Drain
After pouring our walls, while finishing the house this summer, our root cellar filled with inches to feet of water whenever the neighboring farmers irrigated their fields… At first, it was just a couple of inches… No big deal… Until the field right next to us got flood irrigated… Then it was 3 feet of water!
At first, we thought, “no big deal, we will just install a sump pump.” But the amount of water we were getting through the growing season was just too much.
So before moving forward with a garden shed above, we are installing a french drain this coming spring!
French drains direct underground water away from the root cellar foundation.
To install a french drain we are renting a mini excavator, and digging a deep trench around the foundation and out away from the structure. Then, we will be filling those deep trenches with a foot or two of rock and burry it back up.
One of our neighbors close by has a basement that would fill with water every year… Till they installed a french drain. So, this should do the trick for our root cellar too!
Build Garden Shed Above Root Cellar Foundation
I will be updating this post as we go… So bookmark this page and check back in a week or two for more instructions!
Hey! We were curious how things were progressing ! We are at the excavating stage…. And curious how you’re doing your stairs to get down into it ☺️
Can you update us on the progress?
Can I simply just say what a comfort to uncover somebody who truly knows what they’re talking about when it comes to building root cellars on the internet?
Do you figure on putting a concrete top on your cellar, which also provides the floor for your garden house? And I presume you are putting vents in the cellar, one high and one low, for ventilation?
Hi Jay! No we will put a shingled truss on top of the garden shed/potting shed on top on the root cellar foundation! Yes we are putting PVC style vents in for ventalation. One at the ceiling top for hot air to escare and one down low to let in cool air. We may do multiple vents (to help with moisture). Thanks for asking!