Green house questions

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Tora
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Green house questions

Post by Tora »

I am thinking of making a green house to try to keep my banana plants from freezing again this winter- I thought we lost them last winter. I need to at least bring the main stalk/trunk through the winter to get a harvest next year. A greenhouse should also help extend the growing season considerably I think.

The tallest plant is about 4m tall now but I’m not sure if it is maxed out yet.

Im considering making a bamboo tunnel frame or a wooden frame (house shape) with some of the excess 4000x 30mm square wood I have stacked with n my driveway. The plan is to make it double walled. That should prevent a hard freeze that would take out the main “trunk” section if nothing else. If I find the motivation, I might put a rocket mass heater in there but I’d like to save all that work for when I can make a more permanent tall, steel pipe tunnel.

The current location is south facing but we are in a bit of a valley so days are shorter.

My questions are:
Is there an ideal orientation for the long/flat wall or roof of the house?

Does a larger gap between layers of plastic on walls improve insulation?

Will I damage the roots if I bury the chimney/heat exchange pipe of a rocket mass heater less than a meter away from the main root mass of the plants? I’m guessing the root ball will not be effected but the outer roots might get a little warm.

It’s in a pretty restricted space otherwise I’d be thinking of a way to make the used 2.3-2.5m pipe frames my strawberry farmer neighbor offered to me work. I’m trying to save angering the wife with “unnecessary” spending for a new wetsuit or some new power tools so this is a low budget project :D

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gonbechan
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Post by gonbechan »

You need minimal gap between layers and then set up a system where you blow air between and inflate the negative space between the 2 layers.

I shall try to find you a youtube for DIY.

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Post by Tora »

gonbechan wrote:
Tue Oct 26, 2021 9:11 pm
You need minimal gap between layers and then set up a system where you blow air between and inflate the negative space between the 2 layers.

I shall try to find you a youtube for DIY.
Thanks Gonbechan!

I’m guessing I could use an air compressor or the blower function on my shopvac to inflate the space between the plastic. I’m just not sure how to keep it inflated through hot and cold cycles. Especially sealing the ends and bottom.

I have an idea on a https://youtu.be/gaudZ6k4TdE bamboo co ... on design but it looks like a lot of work! Seems like the story of my life recently… I could put the inner layer of plastic inside the bamboo ribs with a couple extra ribs inside of the plastic to keep it from sagging.

If I use the dimensional lumber, I’ll just put plastic on the inside and outside if the wood frame like 2x4 house walls. That would give a 30mm air gap.

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gonbechan
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Post by gonbechan »



You could easily use a cheap bath kankisen fan. it needs to be inflated all the time when it is cold.
That video shows a posh greenhouse but you can do it with a polytunnel too.

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Zasso Nouka
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Post by Zasso Nouka »

Curtis Stone's double layered greenhouse is pretty good. You are going to need a fan that can run 24/7 without burning out so maybe don't skimp on that part, last thing you want it it failing in the middle of a freezing cold night. Our poly tunnels get down to -6 or -8 on really cold nights.

As for orientation, I personally don't think it makes a huge difference but if you have the choice maybe orient it North/South but don't worry about it if it's too much hassle.

Don't know much about rocket mass stoves but a lot of folk swear by them so they must work reasonably well. One of the shiitake farms near us uses wood stoves to warm their tunnels with warm air that's blown down the aisles and it works well. The stoves are pretty large as they are loaded up in the evening and burn right through until the morning.

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Post by Tora »

I got the greenhouse up and 2 layers of reused plastic on it. Bamboo construction with dimensional lumber for framing around doors, window vents and channels to lock the plastic in place- similar to the metal and wire channels used on normal pipe greenhouses just homemade. It’s5.5m long x 4.5m wide x 5m high? Total cost so far is ¥3-5000 and far too much time (according to she with the cold glare).

Planning on using a blower to inflate the space between the 2 plastic layers per Gonbechan’s advice and running it mainly on cold days. I’ll have to go back and look at how to connect the blower to the plastic. Might need to spend a little time patching some holes in the reused plastic- it was free…

Not sure if I’ll get around to heating it beyond burning bigger pieces of bio char in our old shichirin or hibachi on Cold days and nights. Might run a fan to circulate air to prevent a hard freeze on real cold nights.

I also found a lot of info on people using compost to heat their greenhouses in winter in extremely cold climates. I am planning a 1x2 meter compost pile on one end. Probably outside with the bottom of plastic pulled up to let heat in. I also have our existing compost bin for mostly kitchen waste inside of the greenhouse now- it was originally next to the banana plants in hope that any compost tea that leached out would feed the banana plants. Not sure if I can leave it there or if I need to move it outside.


So a couple questions:
Is it a bad idea to have a compost pile inside of the greenhouse?

Are there other ways to store heat from sunny days other that a couple big water barrels?

Are there other things that need to be taken into consideration?


This year, although it would be nice, I’m not really attached to keeping the plants warm enough to continue growing (over 13 degrees neeeded to keep plant growing). I’m more interested in the plants surviving winter so I can possibly get a harvest next year and maybe increasing the growing season 1-2 months in spring and fall in hopes of getting the standard 9 months of growth necessary for the plants to produce fruit.

Yes, I realize I am probably insane.
I also realize- NOW - that dwarf bananas would be a better choice cuz they would grow in a normal pipe construction greenhouse but a friend sent me this “sucker” (starter) and it was downhill from there….

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Zasso Nouka
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Post by Zasso Nouka »

That's a pretty sweet price for at size vinyl house :thumbup:. Are you going to post any pictures ? Certainly I'd like to see what you've made and I imagine others would be pretty interested as well.

Can't see a problem having a compost pile in there for some additional heat during the winter, the Paris market gardeners used piles of compost and animal manure to heat their tunnels during the winter. No idea how it would behave in summer, could be fine or maybe not, you'll have to see how it goes.

Water barrels are probably the best material to store heat from the sun, you could use blocks or large rocks but water is probably the most convenient and thanks to convection inside the barrels the heat is distributed evenly around the inside maximising storage capacity.

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gonbechan
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Post by gonbechan »

There is a guy on youtube Swedish homestead or something has an amazing few videos about compost and chickens in a polytunnel.
this is one of them

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Post by Tora »

Zasso Nouka wrote:
Wed Nov 17, 2021 2:08 pm
That's a pretty sweet price for at size vinyl house :thumbup:. Are you going to post any pictures ? Certainly I'd like to see what you've made and I imagine others would be pretty interested as well.
Thank you. I want to post pictures but still dragging my knuckles on figuring out how to do it :roll:

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gonbechan wrote:
Wed Nov 17, 2021 2:21 pm
There is a guy on youtube Swedish homestead or something has an amazing few videos about compost and chickens in a polytunnel.
this is one of them
Thanks Gonbechan. I’ll check that out.

Gotta get it tied down properly. The winds are supposed to really pick up in a couple-few days.