Simple Greenhouse

[DHT]Osiris

Lifer
Dec 15, 2015
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Have a garden shed with a back side that's half paved, half dirt. The dirt half was a dog pen, so it's got some wood framing and a door.

I plan on getting some 3mm acrylic panels and attaching them to the wood framing, and probably adding some framing to the concrete side, paneling that too, then replacing a rotting roof with more acrylic/corrugated acrylic, probably with some kind of hinged panels underneath connecting to the side walls to provide airflow if needed.

I don't know that I need this to be double walled, and I'd prefer it to not yellow (hence acrylic over polyurethane).

Anyone see any flaws, and can anyone recommend tips and tricks?
 

herm0016

Diamond Member
Feb 26, 2005
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check out my posts in this thread:

pics would be great.

what is your climate zone?

we have been very happy with the plastic heavy duty tarp sort of material on ours from https://www.agriculturesolutions.com/. it's 12 mill and made for greenhouses with about a 90% transmittance. I also am a fan of the paralam plastic panels you can get at the big box stores. I have used them on our chicken coop, on the rabbit and turkey hutch roofs, and for temperature controlled windows in the greenhouse. i have had some out in CO for several years and I see no signs of degradation or yellowing.

i have really become a fan of using EMT for structures. i used a connector set from https://sacramentocanopy.com/ for the greenhouse and i have been impressed.
pic under construction: this stood up to a 30 in spring wet snow storm. must have been thousands of lbs on the roof.
20200809_175310.jpg

i also recently used maker pipe for our chicken run rebuild and i will be ordering more connectors from them in the future.


all that to say, we are moving soon and onto more land. we will be buying a large hoop house kit and putting our entire garden in the hoop house, like 30x50 or something. Colorado is a pain when you are trying to grow a lot of your own food because of how dry it is, the bugs, and the short season. we had a few weeks of hot weather, but now the nights are cool again, in the 50s and the soil temps plummit compared to last week. the plants slow way down on adding mass when the soil temps drop.
 

[DHT]Osiris

Lifer
Dec 15, 2015
16,696
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Pics below, this was actually before we moved in, all the crap belongs to previous owners and I'm too lazy to take new pictures right now.
Screenshot_20210629-171117.png
Screenshot_20210629-171133.png

It's not very large, but we don't need a huge amount of space. We'll probably end up supplementing this with another small greenhouse elsewhere. Just making better use of what's already there. We're 5b/6a, get a *lot* of wind, thankfully not from the direction this is facing usually. We'd probably use it for overwintering a few things my cats try to eat, possible seed starters (though plenty of room in the house for that).
 

herm0016

Diamond Member
Feb 26, 2005
8,498
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looks like a good start. remove some of the roof and cover with the paralam panels. do the same for the walls. run some 2x across and then hang the panels vertically. the concrete will soak up the heat in the winter and release at night, so will the back wall of the shed. you could paint that black too. i have 12 55 gal drums full of water for heat mass in mine. we kept zone 10 stuff alive in 5a in our greenhouse with only one electric heater for when it was very cold, like 20 below at night. we covered eveything in the greenhouse at night also.
 
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bbhaag

Diamond Member
Jul 2, 2011
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For the side panels and roof have you considered polycarbonate panels/sheets? IME it's easier to work with than acrylic and a little bit more cost effective. It doesn't have that glass look like acrylic does though so there are some draw backs.

Something like this perhaps were a 4x8 4mm sheet is around $72 and one side is UV treated so it won't yellow with age or break down in direct sun after a few years. Another nice thing about the twin wall panels it there is a little bit of R factor there for insulation. Not much but a little.
 
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[DHT]Osiris

Lifer
Dec 15, 2015
16,696
15,650
146
For the side panels and roof have you considered polycarbonate panels/sheets? IME it's easier to work with than acrylic and a little bit more cost effective. It doesn't have that glass look like acrylic does though so there are some draw backs.

Something like this perhaps were a 4x8 4mm sheet is around $72 and one side is UV treated so it won't yellow with age or break down in direct sun after a few years. Another nice thing about the twin wall panels it there is a little bit of R factor there for insulation. Not much but a little.
I thought they all yellowed with age, is that not true with UV treated ones? I'm normally function over form, but there's a beauty facet involved here for my in-laws. I had actually looked at some double walled ones but disregarded as unnecessary... How well does something like that insulate? We talking 10f over outdoor ambient on a sunny day, or 50f?
 

herm0016

Diamond Member
Feb 26, 2005
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on a sunny day, i can get 75 or 80+ degrees over ambient with my plastic covered greenhouse, if i did not have ventilation, it would be who knows how hot. in there. 100+ *F when its below freezing outside. even a cloudy day at 20 or 30k lux increases the temp by 30 or 40 degrees during the day. a perfect clear sunny day is like 120 to 130k lux.

you want the insulation for night time. with just my single layer plastic, i am 10 to 20 over the absolute low at night but that's only for a few min, its fairly linear from sunset temp in the greenhouse to that low point just before sunrise.


Here is a link to my temp/humidity/lux graphs if you are interested. in the summer, we have the front 3 feet rolled up with bird netting instead of hte plastic for ventalation, the storm door window open and 2 temp controlled windows 2 feet x 6 feet that open around 75 degrees, and we still get a little hotter inside vs outside.

 
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bbhaag

Diamond Member
Jul 2, 2011
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I thought they all yellowed with age, is that not true with UV treated ones? I'm normally function over form, but there's a beauty facet involved here for my in-laws. I had actually looked at some double walled ones but disregarded as unnecessary... How well does something like that insulate? We talking 10f over outdoor ambient on a sunny day, or 50f?
Depends but the UV protection will help. I mean lets face it every type of plastic whether it be acrylic or polycarbonate or whatever is going to yellow or get hazy over time and become brittle. As far as R factor goes we use Verolite polycarbonate 8mm twin wall and if I remember right is has an R3 or 4 rating but I don't remember off the top of my head.

Here is a couple of pics I took today at work. This polycarbonate was hung in 1995 so what 26 years ago and it still looks OK. Sure it's gotten a little hazy over the years but no yellowing. Keep in mind it has NEVER been cleaned or taken care. It was hung in place and that was it but all these years later it is still somewhat transparent.

IMG_20210630_131000484.jpg


Close up view. You can see the benching and the outline of some hanging baskets overhead.
IMG_20210630_131025027.jpg
 
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