Tuesday, October 7, 2008

Greenhouse Almost Finished!

My wife and I literally worked all weekend to get our new greenhouse built.

It was much more involved than I thought it would be. There is still a little more work to do but we are very excited to have the plastic completely covering it now. It is 14 feet wide and 12 feet long, but next year we will expand it to 24 feet long. I am calling it a greenhouse because the book that I got the idea from calls it that. Also, the plastic covering is called "greenhouse plastic". This kind of structure could also call this a poly tunnel or maybe even a hoop house.

Instead of explaining the whole construction process here, why don't I just show some quick pictures? Later I will write a more comprehensive "how to" post if anyone is interested.

I think from the previous post, I left you here, with the PVC pipes being put in place:

Even before that phase, we first had to make a spot to put the green house. We wanted to put it in front of the garden by the fence where the early tomatoes were last year, and the kid's garden was the year before that. This spot was too narrow so my wife had a great idea to build a retaining wall to extend the space out another 6 to 8 feet! We had to move a lot of dirt to back fill the wall, but it worked out well. Later we will finish the other half of the wall and fill it too.

This wall created the perfect footprint for our new structure.

We had to drive metal stakes in the ground at each corner and every 4 feet in the middle and then cut them to the right height.

Is that straight? After the metal pipes were secured, I put the big PVC pipes over them.

Here's a picture of my wife consulting the book at this point to see what the next step would be. We got this particular style greenhouse idea from a great book by Jeff Ashton, called The 12-Month Gardener: Simple Strategies for Extending Your Growing Season. I plan to buy a copy because it also has a lot of great cold frame and cloche ideas. More on the book later.

After the PVC pipes were secure, we had to frame up the ends with 2x4s and add pipe supports to the wood and the PVC hoops. In the above picture, I am putting tape over the wire used to tie everything together in order to protect the plastic sheeting.

My daughters came out to check on the progress and decided to come on in. After the walls were finished and everything secured, we stretched and stapled the plastic on the end walls.

After the end walls were done, it was time to tackle the top plastic sheeting.

My wife and one daughter lifted it up to me while my other daughter took the pictures.

We got it put in place, used about 1,000 staples connecting it to the framework, and trimmed off the excess.

We finished just before the sun went down. At this point, the outside temperature was about 65 degrees. Inside the greenhouse it rose to 100 degrees! I still need to install an exhaust fan and get vent windows put together to control the inside temperature but I am encouraged by the fast temperature rise. I built insulated raised beds in half of this polytunnel and we plan to grow salad crops in there all Fall and Winter and then start many early plants in the Spring.

We have more to learn about how to care for plants inside a greenhouse, so any advice is welcome.

Happy Fall Gardening!



It looks awesome, weekend warrior!!!
bravo to you, your wife and anyone else who helped.


This is awesome. Congratulations on a project well done.

rhonda jean

Hi Marc and Renee. I'm so pleased I came to see this. It does my heart good to see people working together for the betterment of their family. I'm sure this will make a big difference to the amount of food you can grow during the year. Do you have any idea yet if it will allow year round production?

I don't have any experience of poly tunnel green houses. My own greenhouse here is a shade cloth house where I pot up my seeds and keep the worm farm. However, I have seen a BBC program called "It's not easy being green", filmed in England, where they erected a poly tunnel to extend their growing period. They had a short brick wall in theirs that they used a a heat sink. It absorbed heat during the day and released it slowly over night. They said it was very good for their tomatoes.

I really admire you both for the work you're doing. I'll be back to visit frequently and I'll put you on my blogroll.

jacqui jones

that looks fantastic...what a great job u guys did
thanks for the pics they really spell out nicely what u did

everythinng ive read lately...but im new the growing my own food days the tunnels r great for the reason u want it. a book i have he changes the dirt in the beds yearly so things dont get deseased. manly because u tend to grow the same crops in the same place more often

i will be watching to see what happens with yours...i want one

Country Girl

Nice blog, came to visit through Down to Earth. That book sounds good, we are interested in extending our growing season here in Maine.
Great Greenhouse!

Country Girl

A how too post would be great. My husband just peaked at it too and he was wondering the diameter and length of the PVC pipes.

DirtDigger (Tessa)

Hey, it looks great! I myself have a small 6x10 greenhouse. My next one will be built from scratch, like yours. A couple books that have really, really helped me- The Four Season Harvest by Eliott Coleman (he did the show Gardening Naturally, a few years back) and Shane Smith's Greenhouse Companion- very good books, especially the Coleman book. Please read them- you won't be sorry.


That's a really handsome greenhouse, excellent work, I'm jealous.

I've been wanting a greenhouse for quite awhile now, but as a renter (for the time being, at least) I don't have that option.

I've got a couple questions about your covering. The plastic sheeting, how durable is it? I mean how many years does it realistically last (if you know)?

Also, are you planning to use a shade cloth over the top of it to help control your temperatures?

DirtDigger (Tessa)

Marc and Renee,

I almost forgot my 2 favorite tools that have really helped me- one is a inexpensive gardening software called garden tracker www.gardentracker.com

The other is a soil block maker that you can get at http://www.territorialseed.com/prod_detail_list/166/3

they have a micro soil block maker, a 2" and a 4" get these and your plants will thank you for it!


Very impressive! Beats my hoop covers hands down. I love how you built it from the dirt moving up! Way to go. Huge success!


Looks great. Can you come over to my house this weekend and do the same for me?


Do you know if this type of structure would work in a very cold climate? We live in the Northeast (USA) and typically get quite a bit of snow. This was my first year with a garden but we have a very short growing period and I lack the room in the house to do much with getting seeds going earlier in the spring. I'm pleased with the harvest we got this first year but having a greenhouse could be a great way for us to extend our growing period.

Thanks for the pictures and link!!


Thank you everyone for the kind words, especially Rhonda for the mention on your wonderful blog. We do hope to keep something growing in there all year long. The raised beds are insulated into the ground and will have small hoops over them for a 2nd layer of plastic. In the heat of Summer, there will be many vents to open and an exhaust fan.

The brick idea that Rhonda mentions is a great one. We have some raised beds two cinder blocks high. If you reach your hand down in the holes it is noticeably warmer. I would say that block or brick would hold heat well.

jacqui jones - you are right about watching the soil condition in the beds inside a poly tunnel. I am new at this too, but I have read that being under plastic continually can raise the salinity of the soil dramatically. I will
try to keep an eye on it(however one does that).

country girl - We will write more about the specifics of how our poly tunnel was built, but the PVC pipes are 20 feet long, 1 and 1/2" in diameter and held in place by 1
1/4" EMT metal pipe.

tessa - Elliot Coleman is the master! The Four Season Harvest is one of my favorite books! We also began using soil blocks this year. I wrote a little about them here.
I will look for Shane Smith's book and gardentracker.com - thanks for the suggestions.

hydroponica - I got the plastic from IGC Greenhouse Megastore. It is 6 mil and is designed for greenhouses and tunnels. It is supposed to last about four years.

Kim - The plastic is supposed to withstand snow. We get some snow but not as much as you. I plan to knock accumulation off with a broom from the inside. If you built a structure like this I would suggest putting more pipes in. Ours are 4 feet apart. Maybe yours should be 3 feet apart?


sorry tessa - the link to my soil blocker posts was wrong. This one should work.

My apologies to all


Thanks for the answer Marc. 4 years, huh? That's definitely a good lifespan for the money.

You can help level out your night-time temperatures by building a brick/rock wall or berm in it. It soaks up the daytime heat and radiates it back out at night. You probably already know that, but just in case...

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