Grnhouse Pit greenhouse with ShelerLogic greenhouse frame??

[WisconsinGardener]

OK - I have this idea. Before I get too enthused about it, I thought I'd try it out on you all.

I've been studying pit greenhouses, and their advantages for a northern climate. Granted, this isn't Canada, but Wisconsin can get mighty cold. I have a small (6x8) ShelterLogic greenhouse that has not proved terribly useful. It didn't really extend the season any better than throwing tarps over stuff at night.

I was wondering about the idea of using my ShelterLogic frame (or a bigger one) and digging down, to set it down further, so that in essence, it became a pit greenhouse. Is this a good idea? The drawback is the plastic cover. I couldn't remove it for the summer like I have with the above ground one, and once it started to deteriorate, I would have to replace it with just plain sheeting.

Another drawback is probably ventilation - and undoubtedly lots of other things that haven't occurred to me, yet.

What do you think? Worth exploring?

 

[Illini Warrior]

OK - I have this idea. Before I get too enthused about it, I thought I'd try it out on you all.

I've been studying pit greenhouses, and their advantages for a northern climate. Granted, this isn't Canada, but Wisconsin can get mighty cold. I have a small (6x8) ShelterLogic greenhouse that has not proved terribly useful. It didn't really extend the season any better than throwing tarps over stuff at night.

I was wondering about the idea of using my ShelterLogic frame (or a bigger one) and digging down, to set it down further, so that in essence, it became a pit greenhouse. Is this a good idea? The drawback is the plastic cover. I couldn't remove it for the summer like I have with the above ground one, and once it started to deteriorate, I would have to replace it with just plain sheeting.

Another drawback is probably ventilation - and undoubtedly lots of other things that haven't occurred to me, yet.

What do you think? Worth exploring?

check into poly sheeting specifically for greenhouses instead of using just dropcloth poly - it's engineered for UV protection ... if that current frame is half decent - think about reinforcing it with some wood - enclose it with translucent poly panels for something more permanent ....

I wouldn't lower the greenhouse frame into the ground - leave that at ground level and gain some additional overhead ceiling space - that's what high houses are all about ....

 

[summerthyme]

I agree that you can do this, with the greenhouse frame at ground level. However, be aware that except during the summer months, there will be a lot of area that doesn't get much sunlight (due to low sun angle).

Ventilation, etc can all be dealt with... adding shade cloth on the south side can help a lot with excess heat, but almost no greenhouse is going to be usable for many plants (except the truly heat tolerant ones) in midsummer. The earth temperature might moderate that a bit, depending on how deep you go...

IW is right about making sure you buy greenhouse plastic when it's time to re-cover it. The cheaper stuff (which isn't very cheap these days) isn't UV stabilized, and will start breaking down in one season, and will be in tatters and shreds in two. This is one main reason I'd rather try building a greenhouse from scrap windows if I had the choice... lots more labor intensive at the beginning, but barring disaster, it should last a long, long time. We don't get large hail here (at least, not often... I think I remember one storm that dropped "quarter sized" hail, but that did no damage, and would have been unlikely to damage greenhouse glass)

If you haven't already, I'd suggest you get Eliot Coleman's book, "Four Season Harvest". He has lots of interesting ideas about extending the season, and harvests something year round in northern Maine.

Our Amish neighbors get around their lack of electricity to grow plants for their home gardens in a couple of ways... by building a small "greenhouse" frame on the house in front of a window, with shelves... (sort of a "bay window", which sticks out 18-24" from the outer house wall). They heat it by keeping the window open in the house.. which likely also helps heat the house on sunny days from mid spring on.

They also make "hot beds", which are double dug, with 6-12" of strawy manure (horse manure works very well) buried under the topsoil. The manure produces an amazing amount of heat as it decomposes, which creates the same effect as if you had buried electric heat cables in the soil. The cold frame above keeps the heat in, and they're able to start most seed types much earlier than otherwise. I have noticed that they mostly grow the less heat sensitive crops in them, though (they start tomatoes, peppers, etc in the "bay window greenhouse" attached to the house). When the season warms up, they remove the cold frame cover and then have a nice raised bed full of lush onions, carrots, greens and other early crops.

Summerthyme

 

[Freeholder]

A pit greenhouse is something I really want to do. A good use for the areas that are shaded most of the time is rabbit cages or chickens in wire runs. Chickens could go outside in the warm months; rabbits could have dens dug into the earth sides of the greenhouse (if they are deep enough). You would need to line these dens with wire mesh to keep the buns from digging out; cementing them would be even better. And some kind of waterproofing would be good, maybe plastic over the top of the wire mesh (but not the bottom). Just make sure it's easy to reach in to check on bunnies and clean the dens out.

Kathleen

 

[Stanb999]

Here is me in My walapini..

 

[Stanb999]

Running a walapini. ours is 8x20. It has a large shelf at waist height on the north and south sides. The north side is for growing the south side is for storage. We have chest height tray shelves on both the north and south side. The walapini stays average. meaning in deep winter it will fall below freezing but only to 25 or so when it's minus single digits. But it will not be much warmer at 20f maybe just 33. Heating it costs nearly nothing, a 20 pound propane tank heats it for 2 weeks in February with temps to the single digits. Then march takes a tank. Then April and May go thru the last tank. so for 3 grill tanks of propane we have a fully heated greenhouse space enough for hundreds of large plant starts.

 

[Stanb999]

The angle of the roof should be 15 degrees above your latitude. Put some Mylar on the north wall to reflect the light. It actually works well. You will likely not be able to use it in the summer. It will become a solar oven. Regardless of the ventilation.


Ask away!

 

[Stanb999]

Here is a pic of the walapini this morning. Low temp was 35F. Not bad for a snow storm. We will have it full of starts in just a few weeks.