How to Build a Portable Greenhouse for under $200, whoops $239 forgot about inflation. Get more time to get ready to garden
With spring being sprung, planting season is hard on us who like to get outside and work. Several years ago I built my first green house and it worked out very nice. I used it for three years and then I built myself a more permanent year round greenhouse. A lot of planning went into that first greenhouse. Three issues were important to me. Price, Size and Portability. All three of those effected my decisions when making the greenhouse.
1st Price as at the time I was living on less than $1400 a month disability pension and every penny counted at the time. Later I started receiving more money due to getting my Agent Orange benefit for my service in Vietnam. That is when I decided to build a permanent greenhouse.
2nd Size as I wanted to be able to move it around the yard till I could figure out what was the best place for the thing. I found for starting plants full sun was fine, but as the season progressed it could get very hot in the greenhouse so I took advantage of a shade tree in the yard to help control the temperature. That was not something I planned but something I learned as I went along. Another part of the size was that I wanted to make the greenhouse with the least possible amount of cutting and as much as possible buying material to fit my dimensions.
3rd Portability. at the time I was doing construction on my property and needed to be a little bit flexable. While I have plenty of ground. It is almost all wooded and the open areas are basically around my house. As where ever it would be setting would be returned to yard status, I did not want it to kill the yard. One part of the project I was building was a new and more permanent green house. My finished size ended up being 9ft. X 10ft. That is plenty big as I had about forty trays of plants. One of the things I do is plant starter plants and sell them to help keep my costs down and help those who need help. Originally I wanted a 12ft X 16ft but found that it would be way to heavy to be mobile and the dimensions did not work without a lot of extra work. I will try to explain why each feature or dimension is the way it is. You can adjust it to meet your own needs.
Overall height is 7ft. length 10ft. and 9ft. wide
This is what my finished product looked like. A standard size roll of plastic is 12' wide by 20, 40, or 100 foot long. The 12 foot width allows a foot of material on each end for fastening the plastic. If you buy the longer roll you can put on a double cover which holds the heat in better. It is small enough a small heat lamp will keep the chill off as long as it stays in the 30's and 40's. I went with a single sheet of plastic and it worked well for me. Notice the cheap thermometer by the door. I had one inside and one outside so I could keep track of the temperature difference.
Pallets make for good walking especially if it is in a grassy area. With all the plant watering it can get pretty sloppy pretty fast. I had room for a row of trays on the ground under the shelves then I went up 2 foot for the first shelf and then 4 foot from the floor fot the second shelf,
As the season went along I cut a square hole in the end opposite of the door and put a box fan to push air in or out of the greenhouse to help control the temperature. As the season moved along the heat tended to get intense and I moved the house under one of my shade trees. By the time I did every thing was already sprouted.
The door latche is utter simplicty and helps keep the hardware cost down. They are functional but cheap and cheap was the key word on this project
Materials are pretty simple.
2 hinges 3inch or 4 inch will work. Pieces of webbing make good hinges to but the door tends to get floppy.
8 pieces of 3/4 inch X 10 foot long PVC pipe.
6 4foot by 8foot 7/16 inch OSB is enough for both ends.
14 2X4's 10 foot long
2 2X4's 8 foot long
2 2X6's 10 foot long
1 2X6 12 foot long
2 1X6 10 foot long These are not in picture, go along bottom
sides to keep weed eater from hitting plastic
1 piece of plastic sheeting that is 12 foot X 25 foot and preferably at least 3 mil thick. ( cheapest is drop cloth 10X25X 3.5 mil)
--this size requires cutting plastic in 2 pieces
6 1X6 salt treated fence panel boards. I get them at Lowe's or you can simply pry some pallets apart to make tray supports. I cut them a little longer than the gap. about 26 inches and put a cleat on the bottom side of each end to keep them from sliding off the shelf supports.
The total cost with the add ons today is $239.94 as priced at Lowe's. Prices on lumber are up because of the hurricanes last year. When I built mine in 2009 OSB was about $5.60 a sheet, right now it is $13.95 a sheet. Before the hurricane it was about $8.50.
It can still be done for under $200 by eliminating the 1X6 vinyl guards on the sides, making the shelf supports out of used pallet boards, but the fence panel boards are salt treated and the water does not hurt them and they will last for 3 to 4 years.
The finished size for my greenhouse ended up being controlled by the PVC pipe. At 8 foot wide I had to much left over pipe. At ten foot wide the pipe was to short at 9 foot wide and 7 feet high the pipe would flex and bend just right and I drilled a hole about 3/4 of the way thru from each side for the pipe tips to go into the ridge beam each hole was about a 1/2 inch from the top edge of the beam.
The back end is two full sheets seperated by a one foot strip, after lining it all up I screwed them to the 2 X6's and put a second layer on the outside two foot wide. The full sheets were cut to seven foot long which is plent high. I am short so I cheated on the front wall. I cut two pieces seven foot long and then cut a piece out of them for the door. I made a one foot by six foot cut. Which reguired a one foot by one foot piece above the door. If you look at the door you can see how I put a 2 foot wide by one foot piece above the door. If you look close you can see how I used 6 inch wide strips to make the door stops.
The shelf framing is pretty simple. I made the outside boards a little longer only for structural support, you will have to make your own curve for the ends. I did it with a jig saw. Each piece of tubing goes into a predrilled hole completely thru the board. Notice how they weave in and out of the shelf boards. When done it is pretty solid. When I wanted to move it I screwed on a 2X4 flat to the OSB on the front and back wall that was 12 foot long and gave me something to lift with. When I got it where I wanted it I removed them. To move it I bought 4 ten foot long round wooden fence posts and fed them in cross wise about 2 to 3 foot apart and as you roll it forward they will come out the back. Tedious I admit but one person can do it all, but two would make it easier.
Any questions you can e-mail me at sclaus2u@hotmail.com and hopefully my instructions are simple enough you can figure it out from the pictures.
The only problem I had with it was that all my plants with big seeds like melons, gourds and sunflowers kept getting dug up and chewed off right after sprouting. Set some mouse traps and found out it was moles which kind of shocked me as they were on the the top shelf.
The only change I would make is to add a board like the one the ribs go into on the inside edge of the shelves goes and put a short vertical piece there also. I always took the trays out to move it, but I think with those extra pieces it would support the shelves when moving. They would also make it roll over the logs easier.
Good Luck and hope you have a Blessed Growing season.
Pictures of My New Greenhouse
When you got lemons you make lemonade. Had a shed and no flat ground so I adapted
A normal door would not do so I made a gravity controlled sliding door
