Any tips on building a greenhouse?

[geezerbiker]

I'd like to build a small greenhouse that would go over a raised bed that would be covered with plastic in the early spring and deer netting by summer.   

My first thoughts are to make it out of PVC pipe but I don't know how to join it to make the roof.  I can't build anything out of wood too save my life...  I'm also considering steel tube because I used to know how to weld and I'm willing to try that again. 

The little green house kits I've found around are tall enough but too short and I think putting 2 of them end to end is too expensive but I might change my mind if nothing else works out...

Any suggestions?

[reliquary]

How tall and how long do they have to be?  You can get some ideas if you search Mother Earth News articles on covering raised beds or if you want simple "hoop" frames, use PVC pipe in any number of different sizes/lengths, covered with plastic sheeting.
 
Drive short lengths of  rebar in the ground on either side of the bed, bend PVC pipe and anchor by slipping  each end over the rebar, making a "hoop" over the bed.  You can make as many of these to get the length to cover the bed; zip-tie the hoops together with a straight length of pipe at the top of the hoop, and cover with plastic sheeting or mesh.

[longwinters]

What Reliquary said is basically what I did.  My raised beds are 4' wide and about 16' long.  I did not want to walk in side the raised beds so I used 10' pvc conduit 1" dia.  I got them from Home Depot for a dollar each, 3 years ago.  The rebar is a good idea.  I used 3" pipe nipples attached with plumbers tape.  If you use plastic get the heaviest mil you can.  You will also need to wrap the long side edges of the plastic around poles or some type of boards and then screw that down to the bed framing .  Otherwise if you just try to screw the plastic down to the raised bed frame the wind will rip it out. I used bricks on the typical down wind side so I could lift up the plastic if I needed to.


Long

[reliquary]

Here is a photo of what I'm talking about, disregard the "sale" stuff.  You can build these for a lot less than the sale price and can make them as tall as you wish.    http://www.wayfair.com/Guarden-Multi-Season-System-Mini-Greenhouse-GKS-L541-K~GUJ1010.html?refid=GX23012606940-GUJ1010&PiID%5B%5D=7438733&PiID%5B%5D=9546084&gclid=CJnG2JaGoLcCFep7Qgod-C8AeA
 
PVC pipe comes in 20' lengths; use painters' dropcloths for clear cover.  Mesh coverings are fairly cheap, IIRC, but I don't use them.

[geezerbiker]

Thanx guys, you've really given me something to think about...

Tony

[charles p]

Just finished a PVC garden cover.  Made my roof using four way connectors.  The rafters will bend in an arc and tie to a bottom edge.  My bottom edge is about 4 feet above ground and connected to metal stakes.  My side netting is heavy plastic to keep out deer.  The top is light weight netting to keep out birds.  Bees can easily fly right in.  Don't glue your PVC until you are finished.  You can also tack it with stainless screws rather than glue (my neighbor did his this way - his rails are galvanized post with chain link fencing.  His roof rafters and ridge are PVC.)  You need to use some 45 degree fittings to stiffen the ridge to the end walls.  Don't forget to frame a door as well.