Thoughts on a Greenhouse

Pbj ak

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The wife and I are wanting to set up a greenhouse. Not sure on the size but thinkw we would like it to be at least 250-300 square foot, but depending on price, bigger would probably be better. With the way things are these days I think we would benefit getting an earlier start on the growing season and possibly being able to sell/trade a few things. Mostly looking to supplement our food supply and having extra to sale/trade isn’t really our goal just a possible benefit.

We have questions like should we buy a kit or build our selves? Also, I’d like to have the hard plastic instead of the plastic sheeting on a roll but it may put things out of our price range. Would you need to have power or would a drop cord ran from the house be enough? I’m not really sure if we’d even need power.

Any of you guys have something similar or know anything about the subject? We’re looking at spending $1500-$2000 but haven’t completely ruled out $4/5000 if we could build something long lasting compared to using the plastic sheeting that comes on rolls.

As always, and help, ideas, or insight is greatly appreciated and I thank you in advance.
 
You tube. I’m in the process of building two small ones (8x12) with hog lot panels. Most folks say they get a 25 degree temp difference between outside and inside just sitting on the ground. Mine are sitting on geotextile fabric which is black so I’m hoping that’ll make them even warmer and I won’t have to heat them. If you have a backhoe available or a trencher, look into geothermal. @MacEntyre is a good brain to pick
 
@Burt Gummer that geothermal stuff sounds really interesting and I do have a tractor I can use although no backhoe.

@MacEntyre I’d like to hear more about this. Do you happen to have a thread talking about the one(s) you have now or the new one your planning?
 
Do you happen to have a thread talking about the one(s) you have now or the new one your planning?

What I have now, which has proven the efficacy, is discussed here.

What I plan to do can be discussed in this thread, if you'd like.

Basically, I want to put Direct Air Geothermal (Earth Tubes) underneath a Root Cellar underneath a Greenhouse. I can go into more detail tomorrow.
 
I taught knots, rabbits and geothermal without a heat pump two weeks ago at Prepper Camp. After the geothermal class, I talked to a fellow from Wisconsin who said the frost line where he lives is 6.5 feet! Tha's deep! However, it made me realize that you could heat both the greenhouse and the ground underneath during the winter. That led to the idea of earth tubes under a root cellar under a greenhouse. You would need to build it such that no water could get into the root cellar, especially water from irrigation in the greenhouse. I have some ideas about that, but nothing I like yet.

First you would excavate the root cellar. Let's say it's got six feet of headroom. Then, you excavate for the earth tubes, either trenches or the entyre area. Let's say the earth tubes are four feet below the floor of the root cellar. That's a total of ten feet deep. It's no small excavation project. However, the benefit could be huge. The idea is that the earth tubes heat the root cellar, as well as the greenhouse above. If it is an insulated greenhouse, with passive solar and heat sinks, then the heating load would be shared by the earth and the sun. I'm not certain it would work in Wisconsin, but it would work in NC for sure!

Not only would you have a year-round greenhouse, you would also have a 55F root cellar for winter and summer storage.

I'd love to hear ideas about how to make the floor of the greenhouse, which is the roof of the root cellar.
 
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This may be a dumb question but do the earth tubes have to stretch the length of the whole greenhouse?
 
This may be a dumb question but do the earth tubes have to stretch the length of the whole greenhouse?
No, but the more length underground, the better. Another way of looking at it is, you want as much underground piping as you can afford.

My shop has 80' of pipe buried 4' down. I consider that a minimum. I have the fan turned down as low as it can go, in order to get the most heat transfer.
 
What I have now, which has proven the efficacy, is discussed here.

What I plan to do can be discussed in this thread, if you'd like.

Basically, I want to put Direct Air Geothermal (Earth Tubes) underneath a Root Cellar underneath a Greenhouse. I can go into more detail tomorrow.
Please elaborate....I have always been interested in this but was told it was expensive. Maybe a fresh thread?
R
 
I don't know what a fresh thread will do for it... Pbj AK says it's ok, so why not here?

Here is the simple issue: without a heat pump, using the earth for direct air heat exchange risks accumulating moisture in the air. In a greenhouse, who cares?

You could still do geothermal without a heat pump and have no accumulated moisture, by running water pipes underground and up to a air/water heat exchanger (like an automotive radiator).

Anyway, such a system is inherently inefficient, as there is no phase change. But it can be done without much money, and might keep a space from ever seeing freezing temps.

What makes geothermal-with-a-heat-pump expensive is that it needs two wells drilled down to an aquifer. One well to pull water from, the other to put the water back. Those wells are at least $6,000 each. Then you need a heat pump, with freon, and an air handler/chiller. Similar to an electric residential system, but with two wells added in.
 
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What makes geothermal-with-a-heat-pump expensive is that it needs two wells drilled down to an aquifer. One well to pull water from, the other to put the water back. Those wells are at least $6,000 each. Then you need a heat pump, with freon, and an air handler/chiller. Similar to an electric residential system, but with two wells added in.
We put in a closed loop geothermal system. There are three wells, 220’ deep with HDPE pipe up and down each well that are then filled with thermal grout. The measurement of the flow meter was 9 gpm and the IR thermometer gave me 46/54 supply return. 8 degrees F * 9 gpm / 24 = 3 tons, the exact size of the system. It has a cooling EER of 40 with one stage (>95% of the time) and a heating COP of 7. Before moving into the home, the only electrical load was HVAC and a few power tools. The electric bill summer or winter was a peak of about $65. Occupied it runs about $135 per month. It also has a desuperheater that is used in the summer to preheat a hydronic storage tank that feeds the instant water heater, so it gets warm water to top off instead of ground temp water using less propane. Overall, with hot water and cooking, and backup generator, the house uses about 150 gallons of propane a year.
 
Well, the wife and I started building our greenhouse. 12x50 hoop house.

I’d really like to do the geotubes but may have to wait a little bit on them unless I can find some cheap materials.

BB8AE63D-8B2F-44A1-8C00-712585F8121F.jpeg
 
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I'd love to hear ideas about how to make the floor of the greenhouse, which is the roof of the root cellar.
My first thought is that you get the same benefit by making them adjacent to each other as you do by stacking them. Dig the root cellar and dig for the earth tubes below it. Bring them up to the surface and run them into the greenhouse that could be built in any direction and not just over the opening you dug.

When we installed geothermal years ago we had 4 wells, each 400’ deep and we ran a continuous pipe. The length of the buried pipe gave us our capacity, not the depth. The temp at 100’ isn’t enough different from the temp at 10’ to make any difference, at least as I recall. So, why bury the pipes under the root cellar?

Assuming that what you want to do makes sense, you can build the cellar pretty much like a basement in a house.
 
Assuming that what you want to do makes sense, you can build the cellar pretty much like a basement in a house.
You have described exactly what I want to do. The benefit to stacking is that you bring the warmth up, that's all. Kinda like putting your wood stove in your basement.

I asked about ideas for the roof of the root cellar because above it will be irrigated soil. If it is built like a cellar in a house, with a floor, then it makes more sense to make raised beds.
 
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Well, the wife and I started building our greenhouse. 12x50 hoop house.

I’d really like to do the geotubes but may have to wait a little bit on them unless I can find some cheap materials.
Looks like you have plenty of room to bury 'em.
 
You have described exactly what I want to do. The benefit to stacking is that you bring the warmth up, that's all. Kinda like putting your wood stove in your basement.

I asked about ideas for the roof of the root cellar because above it will be irrigated soil. If it is built like a cellar in a house, with a floor, then it makes more sense to make raised beds.
I had assumed raised beds, no idea what you’d need to do below irrigated soil.

Don’t understand your comments about heat though. We had a root cellar in central IL and there was never a time when we wanted it to be any warmer, we never added heat to it. There was very little air exchange. I don’t see any benefit to tying the projects together, the tubes don’t work better if deeper and the root cellar doesn’t generate heat for the greenhouse. Seems like lots of challenges with no benefits that I understand.
 
Working on the green house today. Got the northern end boarded up. Figured we’d paint it black to help pull in heat. We’re going to put plastic over the southern end to let in as much light as possible.

I’m thinking about unscrewing the plywood on the northern end and running the plastic sheet between theplywood and 2x4 to help secure the plastic when the wind blows. I thought it might be a good idea to use pool noodles or something similar between the .6 mil plastic and wood so the woods doesn’t cut into the plastic. Does anyone have a better solution for this? The wind blows extremely hard from the north and I’m afraid the plastic will get ripped off.
BDCC0CC5-70FB-4144-9273-FCCDC1142A00.jpeg

Here are some more photos of what I’ve got so far. Any and all input on what I can/should change are greatly appreciated.

The “plywood end” is pointing directly north and the other end is south just for reference.
49281862-FE08-4A44-B4E8-D20AEF5960F4.jpeg9D320793-3979-4BB6-9F52-50337FF13E8D.jpegF68D3ECB-B7F8-4954-BC2A-2BC5369442E5.jpegE73C27F5-B631-4D07-B34F-FA2D5AC981AF.jpegBAC19443-D8F3-4BB5-9B0B-169AE2323C3F.jpegC0F2F2E6-9A59-42CD-95CD-3FBEFEB94117.jpegCDC3834F-3C1B-44D2-BE57-8DBD541967C1.jpeg348BE0FE-F8C7-473A-AAC5-16475DBA4E32.jpeg

Edited to add: do you guys think the zip ties I used to connect the pvc will hold out should I secure them another way?7F15E6DD-F286-4E8E-A409-5230AB057C9A.jpeg
 
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NC used to have a program where they would pay for or reimburse (can’t remember) you for building a greenhouse if it was producing for x number of years. Might have just been western NC. I’m sure there are some incentives or tax breaks you can get to help keep cost down.
 
A lot of growers use high tunnels to extend their growing season. At one time there were grants available. I would check with your local extension agent and they should be able to point you in the right direction.

I’ve been in commercial plant production for the past 20 years and in my experience it’s all about knowing the crops you want to grow. A $1000 greenhouse can work just as good as a $100,000 greenhouse of you know what you are doing.

I have several Quonset style houses but none are made out of pvc. I do know that zip ties I use to hold irrigation systems, shade cloth, etc will only last a year or two.

Frost cloth and irrigation can go a long ways increasing temperature in your greenhouse if it is tight enough.
 
I would reinforce the plastic where it will be attached, a couple layers of tyvek tape or strapped packing tape comes to mind, i’d sandwich it between the two pieces of wood in a way that allows you to replace the plastic as needed.
 
@Pbj ak , zipties aren't known for being UV resistant. Depending on the actual load on them, they could last as long as the clear plastic, or not..
The last recommendation I read was to use wire twisted with the twists on the down side so the dont contact the clear plastic.
 
You need to be able to replace the plastic covering without disassembling the ends. Better to use a wood strip to secure the ends.
That plastic will need replacing every 2 or so years......UV and temperature changes kill it quickly.
R
 
I have 1x’s to wrap the ends of the plastic around and screw to the bottoms of the 48 ft sides of the house. I was thinking about having the plastic running on the inside of the frame ends. Should I run the plastic on the outside of the framed ends?
That plastic will need replacing every 2 or so years......UV and temperature changes kill it quickly.
R
You need to be able to replace the plastic covering without disassembling the ends. Better to use a wood strip to secure the ends.
 
Gemplers has a load of greenhouse accessories.
 
My greenhouse plastic is attached using track and wiggle wire. It works great. I also use batten tape and staples to attach the plastic at the to of the frame.
 
@Wolfpack33, @hp468, @Johnny, @MacEntyre, @JimB

So I have been looking around at wire to replace the zip ties and found out my buddies dad has a lot of stripped copper wire that’s scrap he was saving to cell/sail/sale when prices went up. Some of it is insulated and some not.

Any reason not to use the non insulated scrap wire? Are there any reasons to buy new wire instead of the scrap foot long pieces I can get at a much cheaper price? I don’t mind to buy new but if there’s not going to be any difference either way, saving a little money is always good
 
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The wife and I are wanting to set up a greenhouse. Not sure on the size but thinkw we would like it to be at least 250-300 square foot, but depending on price, bigger would probably be better. With the way things are these days I think we would benefit getting an earlier start on the growing season and possibly being able to sell/trade a few things. Mostly looking to supplement our food supply and having extra to sale/trade isn’t really our goal just a possible benefit.

We have questions like should we buy a kit or build our selves? Also, I’d like to have the hard plastic instead of the plastic sheeting on a roll but it may put things out of our price range. Would you need to have power or would a drop cord ran from the house be enough? I’m not really sure if we’d even need power.

Any of you guys have something similar or know anything about the subject? We’re looking at spending $1500-$2000 but haven’t completely ruled out $4/5000 if we could build something long lasting compared to using the plastic sheeting that comes on rolls.

As always, and help, ideas, or insight is greatly appreciated and I thank you in advance.
Harbor freight sells green house kits
Metal-hard plastic doors and vents
 
@Wolfpack33, @hp468, @Johnny, @MacEntyre, @JimB

So I have been looking around at wire to replace the zip ties and found out my buddies dad has a lot of stripped copper wire that’s scrap he was saving to cell/sail/sale when prices went up. Some of it is insulated and some not.

Any reason not to use the non insulated scrap wire? Are there any reasons to buy new wire instead of the scrap foot long pieces I can get at a much cheaper price? I don’t mind to buy new but if there’s not going to be any difference either way, saving a little money is always good
I’d guess that it’d work well.
 
I would think so too. It is definitely worth a shop. There is a group on Facebook called High Tunnels for Beginners. There is lots of great tips and tricks on there as well.
 
Well I just finished up replacing the zip ties with 12 thhn copper wire. Cool outside this evening.
 
Well, we got some soil tests done and it looks like we need to add some lime. It’s suppose to rain all week and we’re afraid it might not be a good idea to add it until we get the plastic on.

So I wanted to ask, is there any easy way to put it on (plastic top) with just my wife and me working on it? Any pointers would be much appreciated.



@Wolfpack33, @hp468, @Johnny, @MacEntyre, @JimB


Edited to add: I’d like to also get some advise for beginners, like things to do and what not to do. You know, just things that anyone with a greenhouse should know. We’ve done a lot of reading but having pointers from folks with first hand experience would be awesome.

Also, we’re just planning on draping the plastic over the top and using 1x2s to attach it to the bottom. We were running short on funding this and didn’t get to pick up the track and wiggle wire mentioned above.
 
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Well, we got some soil tests done and it looks like we need to add some lime. It’s suppose to rain all week and we’re afraid it might not be a good idea to add it until we get the plastic on.

So I wanted to ask, is there any easy way to put it on (plastic top) with just my wife and me working on it? Any pointers would be much appreciated.



@Wolfpack33, @hp468, @Johnny, @MacEntyre, @JimB


Edited to add: I’d like to also get some advise for beginners, like things to do and what not to do. You know, just things that anyone with a greenhouse should know. We’ve done a lot of reading but having pointers from folks with first hand experience would be awesome.

Also, we’re just planning on draping the plastic over the top and using 1x2s to attach it to the bottom. We were running short on funding this and didn’t get to pick up the track and wiggle wire mentioned above.
When I cover my cold frames I like to start with my end walls. I start at the top and pull the plastic tight at the bottom. This usually gives my students an idea of how to work the plastic and get the wrinkles out. I use staples in a pneumatic gun. I also put batten tape on top of the plastic and staple it down. I start with small strips maybe 1” long or so and then I will go back and staple the whole side.

When you drape the plastic over the side I would recommend getting one side done and then pull it right and secure it right on the other side. If you can get a third person to pull the front and back tight it will really help take out some wrinkles.

As far as tips go just take your time and measure to make sure you have enough plastic to cover everything. One of my cold frames is a strange size and sometimes a 100’ roll of plastic will be a little short and it makes it really tight. I’m a lefty and suck with scissors. Make sure you cut straight and square.

Good luck! It’s really simple to do but it does take some time and practice to get the wrinkles out and make it tight.
 
Ah man stapling would be nice but I don’t have an air compressor or a staple gun. We ended up wrapping the plastic around the 1x2 and screwing it out down. I hope the plastic doesn’t tear. Was thinking about putting another row of 1xs on top of the ones wrapped with plastic, just for a little support.

Still have to finish the end. Hopefully it will be done tonight. I got 40 lbs of lime today and was hoping to spread it tonight too. I guess we’ll see what happens.

This has been a lot more work than I though when we first started talking about a green house.
FC8485D5-5D10-4B05-8D2C-CBA555D5FC51.jpeg
 
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1230am and we’re done for the night. Got both ends to a good stopping point where the wind (hopefully) won’t blow anything away. Ill post a few more pics tomorrow along with another question or two.

801F4AC0-AEC9-46D6-8FB5-51BE7BBF4C0D.jpeg348A776F-0E05-4EC3-8B30-9402CF9A41FE.jpeg
 
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