PitGarden.com

Building a Pit Garden Start to Finish

It was roughly 9 months ago that the Walipini concept was thrust into my consciousness.   At first it seemed like a pipe dream, but research led to a design, which led to getting the right equipment on our homestead for building something like this, and then there was a big hole in the ground, etc.   One thing leads to another and a random post on Facebook turns into a fully functional pit garden!  This post is the culmination of all that work.  Seeds have been planted, and thus this project migrates from designing and building a pit greenhouse to using a pit greenhouse to grow amazing organic produce year round.  (At least we hope!)

All of these posts originally appeared at A Prepping Homestead, where you can follow our adventures in all things homesteading, but for pit gardening in pit greenhouses this is the site you want.   Here at PitGarden.com we also has forums where, with your help, we can hopefully build a great community resource on Pit Gardening.   I’m hopeful that many of you will want to participate as I know at least here in Montana I run into many people who have read about and are interested in this form of greenhouse, but yet I couldn’t find answers to many questions I had during the process of putting this together.  With your help posting in the forums, and even creating blog content (email me Andrew@APreppingHomestead.com if you you want to create a guest post), we can evolve this concept further.

Please keep your eyes on these pages as in the not too distant future there will be a physical and E-book available that goes into much more detail on the whole pit greenhouse project. Here are the articles, in chronological order (Feel free to click on just the first, as each post will link you to the next):

Pit Greenhouse Design

Pit Garden Supplies -- Supplies, Materials, and building techniques used on this project.

Pit Garden Supplies — Supplies, Materials, and building techniques used on this project.

Background

Pig Garden Digging — What can I say, a pit greenhouse by definition is a huge hole in the ground.

Pit Garden Footing -- A sturdy building starts with a good footing.

Pit Garden Footing — A sturdy building starts with a good footing.

Pit Garden Walls -- You have to keep the dirt out somehow!

Pit Garden Walls — You have to keep the dirt out somehow!

Pit Garden Fill -- Backfill and Interior fill

Pit Garden Fill — Backfill and Interior fill

Pit Garden Entry -- Sliding down a snowy embankment all winter just wasn't going to work...

Pit Garden Entry — Sliding down a snowy embankment all winter just wasn’t going to work…

Pit Garden Roof -- The last piece to an enclosed structure

Pit Garden Roof — The last piece to an enclosed structure

Pit Garden Finishing Touches -- What was left before we could plant

Pit Garden Finishing Touches — What was left before we could plant

Pit Garden Automation -- Or how I'm lazy and don't want to walk out there to turn on the grow lights.  :)

Pit Garden Automation — Or how I’m lazy and don’t want to walk out there to turn on the grow lights. :)

Solar Heating Greenhouse

The Power of the Sun!

Heating the Pit Garden -- The sun has been great, but  if you want to start tomatoes in January you need a little extra heat.

Heating the Pit Garden — The sun has been great, but if you want to start tomatoes in January you need a little extra heat.

If you didn’t, please click those images above to learn more!

Andrew Blessing

Pit Garden Finishing Touches -- What was left before we could plant
Check out our post on automation for the lights and heat in the pit garden.

29 Comments

  1. Would it really be warm enough in the winter? I am in west Michigan.

    • I’d say the jury is still out. I’ve heard stories of people growing year round in our climate (we’re in SW Montana) without supplemental heat. This year we’re needing to heat just to catch up since we sealed it off in sub zero temps and didn’t get any of the advantages of starting out with a nice warm pit.

      I am certain that we’ll need to use much less heat than we would with an above ground greenhouse. If you create an inexpensive way to heat in Dec and Jan such as a rocket stove, or for us excess solar power, you’ll get through the year no problem.

      Or no doubt you can utilize the pit 9-10 months of the year without any heat, which is a whole longer than the 3-4 month growing season we get outside!

    • Unheated, it’s certainly warm enough for cold-tolerant crops like carrots, kale, spinach, swiss chard, scallions, oak leaf lettuce and arugula. Check out the Winter Harvest Handbook which is based on quick hoops and cold frames, all at ground level. The pit would probably allow you a broader range, even without additional heat.

  2. I am wondering if you are finding that the stairway is causing a cold tunnel effect when you enter and exit the greenhouse? Since cold air likes to pool in lower areas would building a longer tunnel entrance with a second door help minimize the loss of heat? We live in an area where winter temperatures can be -40F for a week at a time. To keeping cold air effects to a minimum we build airlocks ( double door systems) and I am wondering if they would help in a system like this.

    • An airlock might definitely help. I’ve thought of doing that with just some sort of plastic sheeting on the inside. So far though we’ve been OK, though possibly because we’re having an abnormally warm winter thus far. One thing we did do was have the lowest point be the bottom of the stairs, and then 2nd lowest point be the entry way inside the pit to allow the coldest air to settle below the entry way outside, and below the garden inside.

  3. Larry Iles Reply to Larry

    Building walls around the entrance (at the surface) with a roof and an outer door would solve several problems. 1. It would eliminate any accumulation of snow on the stairway leading down to the greenhouse. 2. It would create the airlock to prevent heat loss. 3. If you used the same clear material for the walls and roof as you did for the greenhouse, it would provide both light and heat to the enclosed stairway. Just a thought.

    • Larry, absolutely! We’re planning on it but I just ran out of time this month to finish up that step. Not sure about the clear material though, it loses a lot of heat at night without our insulated tarp on it. I think keeping the snow out and thus my not having to clear the stairs every other day would be the most important assist. :)

  4. I have a couple of questions, but first, congratulations on this project! I want to do something very similar – it just makes so much sense. I’ve been able to find precious little information about it, and am very happy to see what you’ve done.

    Questions:
    Do you have any concerns about radon and if so, how will you handle it?
    The plastics used for planting and water – is there a concern about toxins leeching into the water?

    I’m trying to convince myself that I won’t be having any more kids so I don’t need to worry about BPA, but I still do.

    Again, congrats on your design and getting it all put together just before winter hits. It’ll be exciting to watch it grow!

    • SLM, interesting questions… We do have Radon in our neck of the woods, but just at the EPA’s limit, not horribly above it. We’ve never been too concerned about it in our home, but definitely don’t live in the basement. Nor do we spend a lot of time in the pit greenhouse, so I’m not worried about us.

      You got me thinking though if maybe the plants shouldn’t be inhaling it and thus eating it. Quick research on Google indicates no information that this would be bad, and even showed a study that suggested that a little bit of Radon radiation may help plants grow!? I’m no scientist, definitely do your own research.

      As for the plastic? Well believe it or not those trash cans that we use for watering are actually safe for food storage so I’m guessing they’re BPA free? That said, I don’t the levels that could make it into the plants, and from them into us, are something to worry about. Again, though, who knows!

      Thanks for the kind thoughts, when you build yours please post pictures of it in our forums!

  5. Rob Steel Reply to Rob

    I would suggest a cellar door type setup to cover the entrance. Might help keep heat in and will keep out leaves, snow, rain, etc.

  6. Thanks for sharing this. I’m recently in northern New Mexico from Ohio and am finding the short growing season unbearable.

    • Debbie. Not sure how close you are to Taos, NM (its beautiful!) but you should check out “the greater world” earthship community. and check out earthships in general… they are pretty darn cool!

    • Debbie,
      You can go below ground or above ground in year-round, well-insulated greenhouses that use passive solar design in many climates. Check out ceresgreenhouse.com

  7. Mike,
    Awesome to see someone building a pit greenhouse with insulated, structural walls. We (a solar greenhouse company in Colorado) get a lot of people thinking of going about this by just digging, putting on a roof and calling it a day.
    I wonder about your glazing angle though. Particularly in Montana, the angle of the sun in winter has to be very low — did you evaluate whether it would reach plant height? Perhaps that’s in another post. Thanks for documenting and sharing.

    • Lindsey, thanks for stopping by. We did do some evaluation on the roof angle. It was a trade off based on a few different considerations. The design diagram from our design post goes a bit into sun angle and I was able to simulate the angle on the side walls. What we found was that the raised beds in the back get sun 100% of the year, as well about 50% of the raised beds on the ground. The rest we’re getting sun through the reflective surface on the back part of the roof. This angle was designed to reflect light to the front of the pit when the sun is at the lowest angle of the year and seems to be working well. That said, we’re using grow lamps a bit to assist with what we’re missing sun wise in Dec and Jan.

      • Nigel Gray Reply to Nigel

        I like your project….we are considering a similar thing here in New Zealand. My idea was to have grow lights also, and power them using solar AND wind turbine. This is realistic as we live on a plain that is incredibly windy at times as the wind channels through from the mountains to coast-ward.

  8. Connie Rigsbee Reply to Connie

    My Hubby is a brick Mason!! I have really been wanting a greenhouse but was thinking of a traditional set up with Aquaponics and a wood boiler to heat it AND my house. Now I must think long and hard about which set up would work best. I am in NC so this would really work with our winters! What material did you use for the windows on the roof?

  9. I already have a pit (aka Swimming pool) that is big on upkeep, low on use. I would love to make it into a garden. Any suggestions?

  10. Congratulation ! There are lots of good ideas in this project. Being from Québec, one of my concern would be the accumulation of snow on the glass roof; Would it melt or not and how easy would it be for us to remove it. How do you handle the snow so far ?

    • So far we’ve had a lean snow year where we are in Montana. Honestly the mountains get a lot but our lower elevation gets 70-80cm. We have ours covered with an insulated tarp, so the snow hasn’t been melting much and I’ve used a roof rake to clean most of it. Then the tarp it self rolls off the rest of the snow. I think if you stayed on top of it you wouldn’t have a problem. This document discusses framing for different snow loads. We erred on the side of caution. :) http://www.sundancesupply.com/FramingGuide.pdf

  11. Hey great project! im very much into sub terranian structures including walipini’s. The earth is an amazing insulator and thermal mass retainer. The key is though to keep the soil dry and insulated around your structure so that you can hold that heat in your storage zone (behind your building). If anyone is interested in sub terranian heat holding structures (earth shelters, earthships) You should definitely give this book a read, Im currently building an earthship in canada. And this book gave me great insights. Good luck on your project.

    http://www.goodreads.com/book/show/21251621-passive-annual-heat-storage

  12. Looks terrific! How are your plants watered? Any thoughts re rooftop catching of rainwater and/or snowmelt? If you had a blizzard with three feet of snow, might your pit garden’s roof be strong enough to withstand the snow’s weight? Or would you advise a steeper garden roof in climates with lots of snowfall?

    • Thanks Rob! We water the plants with water out of our heat sink trash bins filled with water. Check out this link about adding spigots to them: http://www.apreppinghomestead.com/build-a-water-barrel/ We definitely could go to collecting rain water and or snow melt, but right now just fill these using our well water. I did calculate our snow load and built appropriately for our location here in Montana. I wouldn’t want 3ft of wet snow on the roof, but when it’s snowing I clean it off each day so we never really collect more than 6-8 inches which doesn’t even sag it. Certainly a steeper roof could be used, but there’s a trade off there as you want minimal air mass above the insulated walls of the ground. A steeper roof though would also allow more light in, but you’d have to move the shed snow away from the pit anyway in order to not block the solar energy when the sun came back out. Certainly every environment and use is different!

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