Building and Using a Window Well Root Cellar

A Window Well Root Cellar is turning out to be a pretty effective way to store out potatoes over the winter.

Window Well Root Cellar Update 1-2017

This post is a first year report on our new window well root cellar.

In the fall we always have a lot of produce that needs to be stored in a nice cool area. Potatoes, apples, onions, and winter squash should be stored at temperatures above freezing and below 45 degrees. The best place to store them would be a root cellar. But we live on a small urban lot, and there really isn’t room for a cellar.

For years we’ve tried storing our potatoes in our garage. It’s a non-insulated garage so in the winter time it gets pretty cold but it never freezes. The problem is on a nice warm day it will get almost as warm in the garage as it is outside. In the fall before the cold weather sets, the garage is actually quite hot around 75 to 80 degrees.
This is just not an ideal place to store all of our fresh veggies. We’ve tried coolers and boxes covered with burlap. But they never seen to stay cool enough in the garage. We also tried the basement but temperatures there stick around that 65 degree mark almost year round, that’s too warm for storing most veggies.

Because we don’t have a cold spot for storage we end up having to rush to use up all of our potatoes and other winter stored produce. Many years we will have 250 pounds of potatoes and 50 pounds of onions along with various squash. Trying to eat that all up before it goes bad in December or early January is pretty tough and we ended up throwing some things out.

Window Well Root Cellar 1
But I do have a couple of deep window wells that are on the east side of our house and don’t get a lot of sun exposure. That got me thinking that this might be a good place to store our potatoes. So this year I decided to give it a try.
Here’s what I did:
Window Well Root Cellar 2

1. I cleaned out the window well and made sure there was nowhere for pests to hide. I was particularly concerned about mice. So I added a few mouse traps, and I made sure to have one of my mouse boxes out in the garden in the fall to catch any strays.

Window Well Root Cellar 3

2. Next I bought a piece of 2 inch foam insulation. And built a plywood frame to hold it down. You can see from the picture the frame is just a couple of pieces of scrap plywood nail together with some 2 x 4’s.

Window Well Root Cellar 4

3. Then I covered the plywood with a little roofing tar paper. I added this just to help the water and the snow roll off the plywood top instead of soaking in. After a pretty severe winter it actually worked perfectly and we didn’t have any water in the window well.

Window Well Root Cellar 5

4. Then I just put everything on top of the window well and made sure that the insulation fit tightly against the top of the window. The well isn’t quite as deep as the window itself which was actually nice because it still left a little sunshine coming through into my office.

Window Well Root Cellar 6

5. I put a thermometer in the window well root cellar to make sure that my temperature was staying where it needed to. For the most part through the winter it stuck around the 40 to 45 degree range.

Window Well Root Cellar 7

6. I also took some of the insulation and stuck it against the windows in 2 pieces so that I could get in and out fairly easily. I did this to keep the heat in the house from escaping into the window well and warming up the window well root cellar too much. On some of the really cold nights, I actually took that insulation out so that the heat from the house would go into the window well.

7. I covered all the produce with burlap or some extra fabric row cover I had lying around for extra protection.

Now this wasn’t perfect.

When we had a couple of nights that were down around zero degrees and I was worried. Those few nights I brought the potatoes in and set them on the ground by the window and then put them back out during the day when it was a bit warmer. That was probably overkill on my part, I never saw the thermometer go below about 38 degrees, but I didn’t want the potatoes to get frozen. But the rest of the winter even on nights where we were down into the low teens the temperature stayed right around that 40 degree mark.

Window Well Root Cellar 8

This quick little window well root cellar allowed us to keep our potatoes all the way through the winter without sprouting. That’s a first for us, usually any potatoes that we can’t fit in the fridge end up sprouting by early January. I’m writing this review in March and we still have about a 75 pounds of potatoes that are doing well. We have seen a few sprout, but I checked them tonight and only 2 or 3 were showing any signs of sprouting. We are a solid two months longer using this method then we would have had been if we had just stored them in the garage or the basement.

I do have a few ideas for improvements:

First I think next year I will put a tarp over the window well to help keep some of the drafts out and add a little extra insulation value. Second, I think I may buy a little more of the foam insulation and insulate the sides of the window well also. Third, I think next year I might build a shelf that way we’ll have more space in the window well root cellar. Then we can move the onions and maybe some squash to this root cellar as well. I also think I’ll buy some more burlap that I can use to cover all of the potatoes, that will add insulation value and keep them all in the dark.

Window Well Root Cellar 9

This winter we kept both potatoes and apples in this setup and it worked pretty well. Now that the weather is warming up we will probably need to bring these potatoes in in the next week or two. But by then there will be just enough left to fill the fridge and maybe even have a few to use a seed potatoes for early plantings.

Seed Starting Banner $15 450x375 copy
In the fall, to cool the cellar down I would leave the top off at night (as long as it was going to be above freezing). Then I put it on during the day I did that for about 5 days until I got the temperatures down to that 45 degree mark. After that it seemed to stick at that temperature even though our daytime temperatures were in the 60’s and even 70’s.
We had a 65 degree day today and I just checked the temperature and we were still sitting in about 48 degrees. Again not perfect but way better than the garage or the basement.
One other warning I would give, I would say you shouldn’t try this in a south facing window well. I think you would have a hard time keeping the temperature down. A north facing window well would be good, but I would watch out, with no sun on it, the temperatures may drop below freezing.

Based on some comments I’ve received I did want to make one disclaimer here.  You should never do this project in a window well that is intended as the only method of egress from your basement.  This is especially true of window wells in bedrooms, do not do this project in a bedroom window well!!  Also be sure that the “lid” is not secured down to the frame of the window well, you need to be able to get out of that well in an emergency.  

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  1. Deborah Davis March 7, 2016 7:27 pm Reply

    Thank you for sharing your healthy, green and natural tips for Building and Using a Window Well Root Cellar with us at the Healthy Happy Green & Natural Party. I’m pinning and sharing.

  2. Clarence Whetten March 18, 2016 8:47 pm Reply

    Thanks for sharing this idea. Please post a follow up next year. Winter squash usually do better if they are not stored below 50 degrees so you may want to keep them closer to the heat coming from the house. I have no problem storing them till late spring in a cool basement bedroom. I find that our dry climate is harder on them than the bit warmer temperature.

    • Mr. Stoney March 19, 2016 11:15 am Reply

      Clarence, thanks for the input, I will continue to update this post as we learn more. Now that spring has arrived it has become a lot harder to maintain that 45 degrees, I think next year I will add a bit more insulation. It also just isn’t dark enough, many of our potatoes are starting to get green, so I think I will add a tarp to help keep the light out. But overall I’m really happy with how this first year went! This is the latest we have ever been able to get potatoes to last. I’m hoping with a little continued tweaking we can keep it cool enough to get potatoes to last until May or early June when our first new potatoes are ready!! Good to hear from you!

  3. Jamie August 4, 2016 8:58 pm Reply

    Pretty cool! Can’t wait to see what you do with shelves. Have you though of putting the window insulation on the inside So that you can slide open the window and access the produce from inside the house? Love the creative solution! I’ve always hated the window wells as a design element. For the first time I want some. 😉

    • Mr. Stoney August 4, 2016 10:40 pm Reply

      Jamie, yes it is 100% accessible from the inside. In fact that is the only way you can get into it.

  4. Diane C Bush January 2, 2017 11:12 am Reply

    This has given me an idea for storage of our potatoes and onions. In middle Ga we have less than 15 days (generally) of freezing weather. So I have been storing potatoes and even tomatoes on the floor, behind some buckets. There is one area that is closed on three sides that will work perfect, especially using the preventive measure you have used. (boink on the head) why didn’t I think of this first?

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