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 :)

Re: My semi-pit banana greenhouse
 

I am building a smaller and different version of this, the frame is wood and pvc and is about 8 feet tall at the peak, not sure how deep i will dig the pit, probably 4 feet. Its about 12 feet wide at the base and will be about 24 feet long for now. I built it so i could expand the length later, and am using a anti condensation and thermal 6 mil cover. I only have one big banana this year so I hope 12 feet of height will be ok. I also bought a roll of weed cloth to put on the floor to keep the thing from becoming a ragweed jungle in the spring lol. I am hoping the black weed cloth, and black barrels filled with water help retain some warmth as well. Do you find that having the pit helps retain a lot of heat?

Re: My semi-pit banana greenhouse
 

:08: :08: Where there's a will there's a nanner.

In my view the main thing the pit does is regulate the minimum temp so that it won't freeze or frost.

It retains some heat, but a lot of the heat is actually lost through the ground. In the winter, the ground in there is always trying to push the temp towards about 45F, so it's easy to keep it from freezing but hard to keep it warm. Since my goal is just to keep it from freezing/frosting, the bare uninsulated floor works fine.

Re: My semi-pit banana greenhouse
 

You have good soil there, here in Oklahoma its noting but rocks, probably going to break my back diggin lol

Re: My semi-pit banana greenhouse
 

Any solar mass like dark barrels filled with water (even milk jugs will help) assist in retaining heat. Open, they'll add humidity.

Personal rant: I so wish people would not use that stupid landscape "cloth". 8 layers of newspaper and woodchips to cover will keep down weeds and give you some kind of soil when the chips break down. Plastic? BTDT. You have to dig it out and good luck getting it all gone. Why not go cheap?

BTW, we called large unheated enclosed growing structures hoophouses when I was up north. I must be getting old...

Re: My semi-pit banana greenhouse
 

Lol Mulch aint cheap here, i got like 200 feet of cloth for 19 dollars, but I do use mulch in the yard, I have to with 105 degree or higher temps in the summer, I even have a compost bin. The plasic I am just laying down on the surface like carpet, just keeps the weeds from poking up but not burying it. All my plants are going to be in pots and containers for the winter, then moved outside in the spring. Without something to hold the weeds down, when you opened the door the greenhouse would explode in a flash of poke weed leaves and purple berries. I think they do still call them hoophouses.

Re: My semi-pit banana greenhouse
 

Okay, I hate mentioning this but old carpet can be used to suppress weeds also; you can find it free by driving around neighborhoods or contacting carpet installers. One man's trash...just a thought...yeah, I"m cheap...I use my funds to buy plants.

I wasn't talking mulch but wood chips. Which are not necessarily free where you live. When I lived in DC, I had all I wanted; it cost to dump them. When I lived in Ohio, tree trimmers sold them to be recycled into that dyed mulch so they were not available. In Jacksonville, where it costs to dump them, it's possible to get them for free but I have yet to figure out how.

Re: My semi-pit banana greenhouse
 

You really hate landscape cloth lol, just kidding.:ha: I might go by a local lumber yard that we have and see if they might want to give some of the chips away. I did see a sign last year that said free mulch there, it should be fine for inside a greenhouse.

Re: My semi-pit banana greenhouse
 

Nope didn't lose anything. Bananas all went semi dormant, but they are coming out of it and the cannas are putting up buds. I started with one cutting of ornamental sweet potato, the lime green kind, and now I have 60. It worked out pretty well, never went below 32F

Re: My semi-pit banana greenhouse
 

Update request? How's stuff in the pit coming along Greenfin? Many casualties...?

Re: My semi-pit banana greenhouse
 

Oops, sorry, was directed to Greenfin. Yes Greenfin, update please.

Re: My semi-pit banana greenhouse
 

My Cavendishes (Williams Hybrid, Dwarf Cavendish, and Grand Nain) and Dwarf Red died down to the ground but sent up pups.

All the Dwarf Orinocos lost their leaves, but their pstems survived almost unscathed. I pruned them back to 3' a few weeks ago (they were up to 6'), though, in an attempt to give them room to push out enough new leaves under the 7' ceiling to sustain a bunch.

One of the Dwarf Orniocos flowered in the middle of winter, so I put an aquarium heater in the pool underneath it in hopes of keeping the bunch alive. It worked, and I think the fingers will start getting ripe in 4-6 weeks.

I think I'm going to have 12-15 bunches hanging in there by the end of July: 10 Dwarf Orinoco, 2 Dwarf Brazilian, 1 purported Dwarf Namwah, and 2 purported Fake Ice Cream. I might get autumn blooms from SH-3640, Gluay Kai, Williams Hybrid, Grand Nain, and Dwarf Cavendish.

On a side note, my Alano sapodilla is budding up with flowers for the first time. It's supposed to taste like a fine pear soaked in brown sugar, which sounds rather tasty, so hopefully I'll get to try one for the first time this year.

Pictures to come later today or tomorrow--after I do my taxes :rollerbananadone:

Re: My semi-pit banana greenhouse
 

Re: My semi-pit banana greenhouse
 

Amazing set up. Too bad about the williams...What happened with the end of the video? I was going nuts wanting to see more!!!

Re: My semi-pit banana greenhouse
 

Haha, yeah, I accidentally hit the stop button on the camera. Meant to say,

"...and after that, it [the DB] started pushing out these sword-like leaves. I'm not sure if the timing was coincidental and these are pre-flag leaves, or whether these are just 'stress leaves', but the next leaf on the way looks a bit more normal, so maybe the plant will go ahead and pump out a few good adult leaves before it flowers. That's what I'm hoping for."

Re: My semi-pit banana greenhouse
 

I see what Banana's are in the pit of your pit.. lol :^)

Re: My semi-pit banana greenhouse
 

Clockwise from the back left, the pit in the pit holds Gluay Kai, Dwarf Brazilian, Grand Nain, and SH-3640. I moved them into the pit late last year when they were already dormant, and they just slowly rotted over the winter. I think if they'd had the chance to get established in there they would have fared much better, more like how the Dwarf Orinocos fared (except for the Grand Nain, which probably would have died down to the ground anyway like all the other Cavendishes). I'm also thinking about moving my Cocos into the pit in the pit to give it room to flower.

Re: My semi-pit banana greenhouse
 

Someone that don't realize what all must have went into this might think it's a ugly weed jungle, but No ! You have a Tropical Magical Majestic rain forest ;) Much respect! Very cool, that's constant work right there! NICE ! Kudos nana bro !

Re: My semi-pit banana greenhouse
 

Thanks. There are indeed some grass/weeds in there, but most of those things that look like weeds are bolting spinach and lettuce. When the bananas defoliated over the winter, I planted lots of spinach and lettuce all around. After gorging on it for a few months, it's bolting and looking ratty. Lots of strawberries along the edges, too: I started with a 7-pack of small starters last year, and now there are hundreds.

Re: My semi-pit banana greenhouse
 

Hey, that was truly educational. Love your quote at the end, too, nannerdeadhead.

Now that we're living in TN, we've been wondering how to grow tropicals and subtropicals here. We have a good sized basement, but not much light in it. Not sure if we'll try building a hoop house like yours, or try growing under led grow lites. LEDs don't provide any heat, so we'd have to insulate the basement a bit (we do have quite a few rigid foamular boards we can use just in case).

You definitely did a lot of digging. No neighbor with a backhoe, or did you do it for the exercise? Just kidding.

Love your photos, and think you did an outstanding job.

Re: My semi-pit banana greenhouse
 

Landlord's rules, no such equipment allowed.

Thanks :bananas_b

Re: My semi-pit banana greenhouse
 

Just wanted to share an update.

I've currently got 5 bunches of Dwarf Orinoco and 1 bunch of Dwarf Brazilian. Several other DO's are looking suspiciously close to throwing buds, as are my Gluay Kai, Cocos (Dwarf Gros Michel), and SH-3640.

Here are some assorted pics. The 1st one is the Dwarf Brazilian, which I've transplanted 3 times and pruned/chopped back several times (thus the small bunch); it's only about 5' tall, but it's also buried 2' deep in the ground, so it's actually 7' tall from the top of the corm up.

Re: My semi-pit banana greenhouse
 

Bump!

Re: My semi-pit banana greenhouse
 

Greenfin, what was the lowest it got in the actual air above the ground in your pit greenhouse? I am trying to figure out how cold it can get with pstem survival. My pit greenhouse got down into the 20's last winter a couple of times, but I am fixing to put another poly layer on it with an inflater. Wondering if I should try to plant a few dwarf varieties in there in the ground, but dont want die back. Thinking of storing potted nanas in there as well, with just burying the pots in piles of leaves with the aim to get pstem survival. Also, how long did your Dwarf Brazilian take to ripen, I read it takes a while.

Re: My semi-pit banana greenhouse
 

Interesting....

I guess it was in palmtalk.org where a member

built a submerged/underground greenhouse.
The problem came during the rainy season>>>>>:rollerbananadone::03:
He couldnt stop the water from coming in.

Re: My semi-pit banana greenhouse
 

I did have a little bit of water come in, but not during normal rains. It was only when we got 4 feet of rain in 90 days (very unusual) that water started trickling in one time. If the pit was very deep, say 4 feet or more, or the water tables are high, I can see flooding becoming an issue. Overall though its worth it, it stays much warmer than outside. Single layer polly film does not keep in much heat at all on its own at night, maybe a few degrees higher, but daytime is another story. Underground it stays much warmer and the heat radiates into the greenhouse.

Re: My semi-pit banana greenhouse
 

The lowest air temp was in the upper 30's. Dwarf Orinoco pstems don't lose any height from those temps, but I do manually chop them back some at the end of winter to try and give them more headroom (since I have a low ceiling) to push out a few more leaves before they flower in the spring/summer. Cavendishes die down to the ground every winter; heck, they seem to pack it in and start dying as soon as the temps drop below 50F.

There's a dramatic insulation difference between 1 layer of plastic and using an inflated double-layer. When I added a 2nd layer to my first tunnel 5 years ago and inflated the gap, the nighttime low water temps inside went up 10-12 degrees.

The Dwarf Brazilian suffered a broken pstem soon after that pic was taken and never ripened its fruit. I thought I had it adequately supported, but the pstem snapped at ground level. I have since built a bigger pit greenhouse and have 2 mats of DB growing in there, but it'll probably be next spring/summer before I'll harvest anything from them.

Re: My semi-pit banana greenhouse
 

BTW, to share an update, I've mostly converted this semi-pit tunnel greenhouse into a 'fig house' and have moved most of the bananas into a bigger new pit tunnel greenhouse. There's only a small patch of Dwarf Orinocos remaining in there, but they've got 5 bunches hanging.

The new pit greenhouse is about 80' long x 17' wide x 11.5' tall (inside height), and the pit is around 4' deep. This will finally give me the headroom to allow some of the dwarf varieties to flourish, and to give me a punchers chance at getting fruit from my bigger projects like SH-3640 and Pisang Ceylon.

The new tunnel will also be holding almost 12,000 gallons of water in various pools, and since I'm going to be maintaining those water temps above 50F (probably above 60F) over the winter, the internal environment should stay warm enough for the super cold-sensitive AAA bananas to flourish.

Here's what I've got started in the newest greenhouse, with the number of mats in parenthesis if greater than 1 (pics to follow, maybe tomorrow morning when it's not so hot in there):

Dwarf Cavendish (5)
Dwarf Orinoco (5)
Dwarf Red (2)
Dwarf Namwah
Dwarf Brazilian (2)
Grand Nain (3)
Williams Hybrid
Glui Kai/Pisang Mas
Cocos (from Encanto Farms...is it the real deal?)
SH-3640 (2)
Pisang Ceylon

Between the pools and those bananas, almost all the space is already taken. But I still have a prime location reserved for Highgate and an area set aside for a couple of orange trees :)

Re: My semi-pit banana greenhouse
 

As I noted above, this semi-pit tunnel greenhouse is on its way to becoming primarily a fig house. I've been moving all of the bananas out and into a new, larger greenhouse that I've just built. There is still a strip of Dwarf Orinoco bananas remaining, though, and they've currently got 5 bunches of fruit hanging.