Back in the days before refrigerators, root cellars served as essential safekeeping spaces for long-lasting produce like potatoes, apples, and carrots, especially through the cold weather. If you’re a modern gardener, you probably don’t need a root cellar to keep vegetables cool, but you may find that having one is useful to store the overflow from a fruitful harvest—and allows you to take back your crisper drawers from those excess zucchini.
Building a cellar by hand isn’t too difficult after some initial planning. For a walk-in, you’ll need to scout a protected location, and potentially do some excavation and construction. That work will add up to more than just one afternoon, but it’s not really as complicated as it seems at first glance. Here’s how to do it.
Picking a Location
Produce lasts the longest in a cool, dark spot with plenty of humidity, so a place that’s underground or at least partially buried will have the best results. If you have a basement that sits below ground level, you already have the easiest and best cellar available. All you’ll need to do is throw up a few shelves and cut off heat to the space in the winter.
But if your home requires something a little more complex, you’ll need to build your own exterior structure. Look for a location in your yard that has a gentle slope to it. Ideally, your location will also face north, which will help avoid the most intense solar heat. Before committing to a spot, check that that location drains well—you don’t want your precious garden fare flooded out after the first rain!
If you live in a flatter region, you may not have a slight rise on your property that will work well for your purposes. If that’s the case, you can hire a backhoe operator for around $100 an hour to help you manufacture the effect.
Planning the Dimensions
When you plot the dimensions of your cellar, think about how you’ll use it in practice. A cellar needs to be tall enough so that you can stand comfortably inside of it, and wide enough to house a set of shelves on all three walls.
A 10 x 10 x 10 space usually works well. Plan on burying at least four feet of the length in the hill itself so that you can leverage its cooling properties.
Designing Your Ventilation System
Any kind of structure needs ventilation, but vegetables in particular give off ethylene gas as they ripen. That means your cellar will not only need proper ventilation, but also good air flow. To accomplish this, plan on installing two ventilation pipes through the ceiling into the hillside above.
PVC pipes work well for this purpose. Designate one as your long pipe, which stops just above the floor of the cellar, and one as your short pipe, which vents air below the ceiling. This has the effect of creating a circulation system, in addition to piping out hot air from your cellar that can hasten the aging process.
Cinderblocks make the ideal building material for a cellar: they’re cheap, breathable, and sturdy. Plan to stack these around the perimeter to build up the walls.
For the ceiling, make sure to use stainless steel beams, rather than wood, to reinforce the structure and keep it from caving in. You can also mix concrete and apply it to the ceiling to add to the effect.
As for the flooring material, it’s a matter of what you prefer. Some cellar owners go with packed earth, since that will help maintain a nice humidity in the area. Others opt for gravel or cement, which helps prevent pest invasions.
You’ll also need to purchase a door. If you can get it, a cheap, insulated front door is often the best option. The insulation offers protection from light and heat—as well as keeping out enterprising critters.
Digging out Your Space
Unless you particularly enjoy digging by hand, plan on hiring a backhoe operator to do this work for you. It’ll run you a few hundred dollars, but it will also ensure that the structure is square and that the floor and ceiling is level. An operator can dig you out in around five hours, while it might take you weeks to shovel out your space by hand.
Before you begin digging, make sure to check with your utilities to avoid hitting local lines. You’ll probably also be asked to obtain a permit for a load-bearing structure, so talk to your local building office before you start in on the project.
After your space is dug out, you can start the work of constructing your walls and your ceilings, laying your floors, and installing your door, as well as establishing your ventilation system.
Setting up Your Cellar
Once you’ve constructed and reinforced the interior surfaces of your cellar, you’ll need to set up the shelves and check that the conditions inside are ideal for vegetables. Opt for stainless steel industrial shelving that won’t rot or warp over time in humid conditions.
Once filled, your cellar should feel fairly humid. If humidity is a problem, you can increase the moisture in the area by adding an open bucket of water that you change frequently. Aim for an interior temperature of around 35 to 55 degrees, checking it frequently.
It may require a little maintenance, but once you have a cellar up and running, the benefits of having homegrown vegetables ready to eat—all year long—make it more than worth it.
About the Writer
Erin Vaughan is a blogger, gardener and aspiring homeowner. She currently resides in Austin, TX where she writes full time for Modernize.com, with the goal of empowering homeowners with the expert guidance and educational tools they need to take on big home projects with confidence.