My semi-pit banana greenhouse
 

I dug out this semi-pit greenhouse by hand last fall/winter using my trusty garden shovel and wheelbarrow. It was a ton of work, so if you're thinking about one of your own, I would recommend using a faster/easier method if circumstances allow.  It's about 55' x 14' x 7.5' and was built using 20' lengths of 1.5" PVC.  It's about 2' deep and is covered with two layers of greenhouse plastic (inflated).  I spent $1,500 or so total and put in around a million hours of labor, but it was worth it :) (click on pics to enlarge)







The lone banana in the pic above is a Dwarf Orinoco that I transplanted there during the winter to provide some size perspective and to see if it would survive.  It was already yellowed and dormant when I moved it in, and it stayed that way until mid-March when it started growing again.  In the meantime I grew greens:


The coldest it ever got at ground level was 36F (outside temps were around 0F), which was great since it was entirely unheated.  Next winter I'm hoping to keep the minimum temp around 45F by adding several thousand gallons of water (in tanks) to catch and radiate warmth.


As it became too hot for growing greens in the tunnel in early spring, I started moving some bananas in:



Then in early May I added some more:  


Here they are at the end of May (left side, front to back, goes Raja Puri, Gros Michel, Double, Williams Hybrid, Dwarf Orinoco, Dwarf Cavendish; right side, front to back, goes Grand Nain, Kluay Khai, Dwarf Namwah, Misi Luki, Dwarf Brazilian, SH-3640):




6/13



6/21







7/20













I'm hoping to have the money to put up a much taller greenhouse (12-15') this fall to house most of these; if not, I'll whack 'em back and overwinter them in there, then move them outside first thing next spring.


Hope you enjoyed the tour :)

Re: My semi-pit banana greenhouse
 

Yeah Dude, you got a cool green house! To bad: too small. Maybe you could lay a foundation with a few layers of C.M.U.'s (concrete blocks), and tie the green house to the top.
I'm jealous tho lol

...._______
../←your greenhouse
/
█ ←8"cmu's
█
█
█___
.......\
Just an idea IDK

Re: My semi-pit banana greenhouse
 

Very nice!!!

Re: My semi-pit banana greenhouse
 

That is absolutely awesome. I was reading about inground and underground greenhouses last year, I intended on doing the same but where I would put it I got 3 feet deep and have a solid plate of granite. In a neighborhood or I would have dug it out with a machine but the neighbors wouldnt let me take down their fence to get it in there. oh well, Im jealous.

Re: My semi-pit banana greenhouse
 

That is one great set up! Looks like you got great soil out there too! Here in northeast ohio we got lots of clay about 2 or 3 feet down. How wide was the soil walls that you mounded up on the sides? Your layout is exactly what I was looking for a possible overwintering project lol.

Re: My semi-pit banana greenhouse
 

Very nice!!

One thing though - If you get even just a little snow per year, really consider that! I don't know how people manage with snow vs pure PVC greenouses, but I've lost two and a lot of money because of just a wee 3 inches of snow piling on pure PVC-based greenhouses. I always now recommend, if people want to do PVC - Put a backbone in it. I've got a 54' x 20' PVC greenhouse that is 12' tall, and had a nice strong wooden backbone to support the center, then wooden supports all down the sides as well. Put a lot of money into the current greenhouse and still constantly need to add more to really seal it up and make sure it's sturdy. We don't get tornadoes or hurricanes or heavy snow, but, we do get constant high winds (45-80 mph) every fall and winter with over 120 inches of rain. The winds can be crazy, but the little bit of snow is often the killer.

Just tryin' to keep you on your toes because that's a beautiful set-up and I'd hate to hear something bad happened. :)

Re: My semi-pit banana greenhouse
 

Great project - thanks for sharing. That's alot of digging. How did you secure the PVC arches?
In my neck of the woods a 2 ft hole like that would be a wading pool. :ha:

Re: My semi-pit banana greenhouse
 

The soil here is really sandy, but there's enough organic matter in it to get good results without much special treatment.

The dirt mounded up around the edge is about 2' wide.

Re: My semi-pit banana greenhouse
 

You raise an important point that folks need to take into consideration.

My strategy for dealing with snow was threefold:

1)make the structure strong
a) use relatively thick pvc for arches (1.5")
b) space the arches relatively close together (3')
c) use 3 purloins running length of tunnel

2) make the structure self-warming (to immediately melt snow off roof)
a) stock with water to give off heat

3) be ready to sweep off any snow that piles up too fast! (I had to resort to this once or twice last winter)


Wind is another possible downfall to look out for. My tunnels are totally exposed and have had to endure sustained 70+ MPH winds on multiple occasions. Without the strong frame and double layer of inflated plastic, my tunnels would be toast. The inflated plastic is a biggie in this regard, as air flows around the structures much better (and with far less force applied) than it would without it. The inflation also prevents flapping/whipping which can quickly shred greenhouse plastic.

Re: My semi-pit banana greenhouse
 

I wanted 20' segments, but Home Depot etc only carry 10' segments, so I special-ordered the PVC through a local lumber/construction company.

With all the strain that I subject these pieces to, I don't trust gluing 10' segments together to form 20' arches. I tested the gluing method back in the beginning, but some failed under heavy strain, so now I don't take the chance and instead just pay more for the 20' segments that I want.

Re: My semi-pit banana greenhouse
 

The green house looks great. :goteam:

Re: My semi-pit banana greenhouse
 

FYI: For wanna bees Should be able to buy 20 ft pvc in stock at your local plumbing supply house.
Yep - great job.

Re: My semi-pit banana greenhouse
 

Whoops, I think I may have misinterpreted this the first time. If you're asking how I secured the PVC to the ground, I bought 10' segments of EBT metal conduit, sawed them in half, pounded them about 3' into the ground, bent them inward a bit, then put the PVC over those 2' pegs.

Re: My semi-pit banana greenhouse
 

I notice a bunch of plastic kiddie pools - Are you going to use those to grow things in? My greenhouse is dotted with them as I find them a very cheap, wonderful way to grow things in a raised situation but not needing tons of pots. I still use pots for things like nightshades, but plants like melons, squash, sweet potatoes, turmeric, ginger, galangal, etc are in my pools. Much more room for them.

Re: My semi-pit banana greenhouse
 

I use the pools to provide humidity and to help regulate temperature in the winter. I also use them for watering the plants. They're a rough draft, though; the plan is to replace them with bigger 300 gallon IBC totes before this coming winter.

I grew bananas hydroponically in a few wading pools last year, and it worked fairly well. I also tried putting dirt in one to use as a big planter pot, but since I just used straight dirt, I ended up with a round, sun-cooked brick. Now I see why people use potting mix ;)

Re: My semi-pit banana greenhouse
 

The weather had been getting too cold for the six bananas that I planted outside this summer, but they were too big to go back into the semi-pit greenhouse, so I decided to dig a pit in the pit.

Once more the trusty shovel and wheelbarrow were called into action, along with a hand saw to remove some of the larger roots.



Gros Michel on the move:


All tucked in:


Left side, front to back:  Williams Hybrid, Gros Michel, Kluay Khai

Right side, front to back:  SH-3640, Grand Nain, Dwarf Brazilian

Re: My semi-pit banana greenhouse
 

Progress report--


The Williams Hybrid is fruiting:


The Dwarf Cavendish just sent up a flag leaf (this DC is a pup of the DC that fruited earlier in my aquaponics system):


The Double is loaded with 16 leaves and looks like it'll be sending up a flag leaf at any time:

The Fake Ice Cream (actually a Namwah) looks like it's at a similar stage:

The Dwarf Namwah, Raja Puri, and Dwarf Orinoco all seem like they could throw up a flag at any time, too.

Re: My semi-pit banana greenhouse
 

Freezing rain has been pelting down outside all day. In the greenhouse, where the air is about 20F warmer, a misty haze hangs in the air.

Re: My semi-pit banana greenhouse
 

Lookin' good.. What's the height from bottom of your bows to the top? :^)

Re: My semi-pit banana greenhouse
 

About 5' from bottom of bows to top of bows.
Main floor is dug down about 2.5' below that, yielding 7.5' of vertical headroom.
Pit-in-the-pit is another 2' down, yielding 9.5' of vertical headroom.

By getting them to lean as they grow, I think I can handle up to about 12' of pstem from the bananas in the pit-in-the-pit. Hopefully the Gros Michel has been sufficiently stunted (after having been dug up and moved 5 times now) to flower at 12' or less :)