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Building A Greenhouse part 1

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This entry is part 1 of 7 in the series Building a Greenhouse

Today I am starting a series on selecting,locating and site prepping for your new greenhouse as well as building your new Greenhouse Kit.

Almost 3' of Snow

The picture above shows what can happen in our area. It also shows that the kits that  we manufacture can stand up to the snow as well as the wind. Note how the snow breaks off of the top of the house as it gets to just over 12″ deep. You might also note that the second greenhouse in the row has no snow on the front 15′ of the roof. That is the house that has heat in the front of it. The back is not heated and you can see where the snow starts again.

I obviously think that the greenhouses kits that we make are the best all around kit. (imagine that).Some of the reasons why are strength against snow and wind. They are big enough to grow in either on benches or on the ground. They are small enough and low enough (7’6″ for the 10′ wide) that they are easier to heat and cool and also stop less wind. These kits are attached to the ground with a 24″ long stub. The bow drops 6″ into the stub and the 2×4 that acts as the foundation frame is bolted to both the stub and bow. If any part of the greenhouse is going to blow away the whole thing has to go. That’s not too likely of an occurance and has never happen yet.

Shown above is a house under construction. Tomorrow we will start building a house by defining the best site on you property and the best way to locate the house on it.

If you want specifics on your site leave a comment.

Building A Greenhouse part 2

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This entry is part 2 of 7 in the series Building a Greenhouse

10'x15' Greenhouse

The greenhouse above is a 10×15 that was installed for a customer. The installation took 6 hours. We have installed about 30 greenhouses so have gotten the time down. If you are installing your own there is no race with time though. If you take your time and plan the installation step by step you will make fewer mistakes.

First I like to find a fairly level spot that is going to be easy to access from your house.I have built greenhouses with every exposure, North to South East to West and any angle in between. If you face the ends North to South then the West wall can get pretty hot in the afternoon. I know there are some rules out there about orientation but I find that it’s easiest to locate it so it’s convenient  to use.,so orient it any way you want.

If you are starting with a grass area I would mow the grass as short as your mower goes then put down some ground cloth and start building. I have a lot of clay so I put down some 3/4″ gravel and put the cloth over that. Don’t use plastic under the house it just causes sitting water and problems with algae and fungus growth. The ground cloth drains very well.

Next find your four corners. You can use a long tape measure to find the diagonal distance between opposing corners. After finding the corners I will dig a hole with an auger or post hole digger. The hole doesn’t need to be more than 8″ in diameter, and just over 12″ deep. The stubs that go into the holes are  24″ long and have a hole drilled at 4″ from the top. With the holes at the corners ready I will place the stubs into the them so that they are plumb and so that the top is 6″ above grade. The holes in the stubs should be about 2″ above grade and facing each other across the front of the house. Then level the  front two stubs across the tops from one side of the house to the other. Now you can mix a 60pound bag of redi-mix and dump it into the holes. I then do the back two stubs leveling them across the tops also. I don’t try to level the stubs from front to back. I just run a string from front to back and pound the other stubs along that line on 5 foot centers.

Tomorrow we will discuss bolting the frame together.

Building A Greenhouse part3

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This entry is part 3 of 7 in the series Building a Greenhouse

Stubs with bows and foundation frame

The above is a picture of how the frame foundation (the bottom 2x4s) hook together with the stubs and the bow sets. The stub is set in the ground, the 2×4 is laid on the outside of the stubs, you now drill through pre- drilled hole in the stub and through the 2×4. Then the bows are dropped down 6″ into the stubs with a clamp on them so they only drop down that 6″ and you drill back through the 2×4  from the outside going back through  the stub that now has the  bow in it. Bolt together and you are off your knees.

Next comes the knee braces, they are what keep your greenhouse from acting like an accordian  when the winds hit the end walls. On the picture above you can see the knee braces at the front of the greenhouse attached to the end bow and extending down at an angle to the foundation frame 2×4. You can see also that they are on the inside of the greenhouse and are attached with a self tapping sheet metal screw into the first bow and with a sheetrock screw into the 2×4 frame rail.

After the knee braces I attach the center purlin pipe at the center of the greenhouse at the top on the inside. Same idea. Use 1/2″ electrical conduit and attach to the bows with a 1 1/2″ 10 gauge self tapping screw. Then space the side purlins about 3′ off of the center purlin.  With the stubs in the ground  the foundation frame and bows bolted to the stubs and the knee braces and purlins installed it’s time to think about benches before starting the end walls.

As you can see in the picture above as well as the one below the 2×4 that I call the bench rail is attached to the bow sets about 33″ above the ground. They are attached with 2″ long 12 gauge self tappers.This height works best for me.

Now you drop the 2×4 or 2×6 end wall footer flat on the ground between the two end stubs. It should stick out past the end of the greenhouse by an inch or so. You will be setting your plywood on this footer and leaning it up against the end bow.

End wall First Panel

Note if you are building a 10′ wide house as shown here, you want to rip this panel down to 3′ wide.( Also note in this pic that there is a second 2×4 about 1′ above the foundation frame. This is for a greenhouse that is bumped up one foot). Now you attach the panel directly to the end bow with 1 1/2″ self tapping screws. Note the nailer in this pic also. This allows you to attach the plywood at the bottom of the sheet to the end wall footer board.  Now from the inside of the house you can set your sawzall or jig saw right on the bow turn it on and follow the bow down until the extra plywood falls off. You can see the piece of scrap behind the greenhouse in the last picture. Easy peasy.

More tomorrow on the end walls.

End wall panel cut flush with the end bow

Building a Greenhouse part 4

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This entry is part 4 of 7 in the series Building a Greenhouse

Display House 10'x10'

Above is a greenhouse I used for a display at the Portland Home and Garden show last year. This is what the end wall should look like before you put the transom piece above the door. The opening in the center for the door should be 49″ wide so that you can put a full sheet of plywood in for the door and still have some room on the sides of the door.The plywood is sitting on top of the end wall footer. I happened to build this house inside of a 20′ wide house so I could keep dry.

Here is another example with the transom in place. Note the 2x4s along the sides of the door frame. I usually build them a little different. I will turn those flat 2x4s on edge and not use a separate frame as shown here. My frame is incorporated into the door itself. I will usually measure the opening of the door opening after installing the transom board. The width will be  49″ to fit the 48″ door and whatever the height of your opening is less about an inch and a half. So the door ends up one inch narrower and  one and a half inch shorter than your rough opening. When you install the door set it on a piece of scrap 1/2″ plywood that is sitting on the end wall footer 2×4. After you attach the hinges remove the scrap plywood and you will have a half inch of gap at the bottom of the door. This leaves room for some sag. There is also an inch of open air above the door. I will sometimes staple a strip of plastic over that opening, that way the greenhouse can still breathe but the cold air won’t blast in above the door.

I don’t believe in a very tight greenhouse. I think it leads to more moisture problems that can help cause diseases among your plants. As stated before you should have at least one fan and preferably 2 running all of the time in a heated greenhouse that you are growing in.

Below is how I attach my doors. Note that this greenhouse has a foundation frame that allows me to use sand bags to keep the house in place because it’s sitting on asphalt.

One more pic below to show you the base of the greenhouse not attached to the ground. This was a display house that sat alongside Interstate 5 in Washington for several months. This is the method I suggest to folks that are using their greenhouse for a chicken tractor.

More on greenhouse building tomorrow. If you have questions please ask. PLEASE

Building A Greenhouse part 5

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This entry is part 5 of 7 in the series Building a Greenhouse

Ready for Poly

Here is a greenhouse with all of the components installed and ready for the poly cover. Unlike other greenhouse kits mine come with the poly. Most don’t and folks end up getting some from the hardware store that usually lasts less than one year. I include a 6 mil uv protected greenhouse poly. One layer works but two is claimed to save up to 30 percent on heat. I use 2 layers and am still waiting for that savings. Maybe it comes in a check someday? Seriously though I think one layer if plenty. Note the picture above and the ground cloth used. This is a heavy duty weed blocker. It also helps to keep the bugs down. No grass or weeds so there is nothing for the pests to chew on.

Here’s a close up of a house that was just covered. Note the 1″x3″ lath used in the sides and the end walls. The ground cloth ran wild here but ends up as a nice porch.

Short post today. More tomorrow.