The Magic of a Walipini
Updated: 6 days ago
I refer and show my walipini, “place of warmth” often on my Facebook page Goshen acres homestead and I get lots of questions about it. I decided it is worth its own post! A walipini is an underground or pit greenhouse meaning, place of warmth.
Here is the thought process on how they work. In my opinion they do not work quite the same as a regular “on the ground” greenhouse. They are superior to them. My greenhouse loses plants from cold temperatures LONG before the walipini and the walipni will stay warm enough that cold loving plants like brassicas, tender perennials and greens will grow or stay alive all winter season.
Now let me preface this for you. I live in zone 4, getting temperatures well below zero for long periods of time during the winter are common. Our last frost date is the end of may and the first freeze has happened as early as September. This makes for a very short growing season. By utilizing the walipini, I can extend my season DRASTICALLY.
So what is this magic greenhouse? It is literally a pit or hole dug into the ground with a glass covering at an angle to the south facing the sun. There are many different building plans and I do wish that mine was built different. If I was to start from scratch, I would make it with the back north wall a solid wall that would absorb the heat of the sun during the day to radiate it back at night.
The other benefit of the walipini is that it is dug down into the ground which provides a constant temperature from the depths of the earth. By capturing and utilizing the heat and storing it for the night when the sun goes down you can still have “heat" inside.
I had wanted an underground greenhouse since I have learned of them. When we moved here, there was one already and waiting! It had been built years ago though and was deteriorated from age and the years of drying from the sun beating into it.
A couple of years ago we tore it down and rebuilt it. I wanted to make some adjustments to what we already had to try to improve it even more. This time we used blocks for the foundation, instead of the wooden beams that were original. The blocks will not dry rot over the years and also should act as a “battery” or storage of heat.
We also dug down the beds in it and replaced the existing soil to put in new soil to refresh the nutrients. First, I had an idea! What if we ran tubing out there filled with water that was heated by the wood stove from the house? It would be free heat and seemed like if there was a little warmth deposited into the bed below the plants then it would add warmth over all. This sounded like a good idea to me! I headed to Kenny the “project manager”, to give my idea and request. What we did was bury pex tubing in the bottom of the bed and then covered it with the new soil. This way if it happened to ever freeze it wouldn't break like pvc would.
This has been a project that is slowly evolving, as do most projects around here. Just keep adding and tweaking until you have a satisfied project. If that is ever possible, it seems there is always new tweaks that can make things better. It is hooked up to circulate from the house, but it needs to be closer to the stove to heat more. Kenny has been thinking of the best way to do this and I think his last thoughts circled around making a coil and mounting it up to the back of the stove first to preheat, then into the existing warming tank. Hopefully that will get done this year. I also will try to get a better insulated curtain for the inside door and put more “batteries” around to collect the suns heat. I‘m hoping that with each tweak it will just keep improving the results.
For right now though, it holds plants all winter and I can slowly glean off from them throughout the winter. I have learned that I need to have a good number of established plants already growing.
This picture is in December, after inches of heavy snow and temperatures almost to single digits. The tender plants like the tomato and basils are wilted and gone, but the hardy... march along. It makes a beautiful place to just enjoy a warm cup of tea and enjoy the sunshine in the depths of the winters cold when you have not seen plant life for months. Such a welcome sight to shovel out the door and go down inside to your own special winter garden.
by fall because in the winter they stay alive, but dont grow a lot. Hopefully with each warming improvement it will increase output.