I was looking for a way to grow lettuce and spinach over the winter so made these hoop houses to fit over my raised beds. These will double as a holder for bird netting next season to protect strawberries. I was very pleased with how they turned out and they only took a couple hours to make. Also, they are very economical compared to a lot of other options I was considering. Total cost for my 3 hoop houses in these pictures was under $35 and I have enough leftovers to make another 3 for only $12.

Material List (prices are for a 4 hoop house)
1/2" diameter dowel. A single four foot piece can make 12 "hoops" which enough for most beds. $1.68
1 1/2" corner brackets. You need two per hoop. $5.80 for 8 brackets.
1/2" garden irrigation hose. 50 ft should be more than enough with plenty left over. $8.41
Clear Plastic Sheeting. I used 4 mil in a 10' x 25' roll. $11.47

Tool List
Saw (miter saw is fastest, but a hand saw would work too)
Drill w/ 1/8" bit
Phillips head screw driver
Razor / knife

Step 1: Make Dowel Anchor Pins

Cut the 1/2" dowel rod into 4" segment.
Drill a hole in the end of the dowel using a 1/8" drill bit.
Mount the dowel segment on the outside hole of one of the corner

Step 2: Mount Dowel Anchors Onto the Outside of the Raised Bed

I placed one approximately every 2-3 feet

Step 3: Run Irrigation Hose Between Dowel Anchors

For my raised beds, I ran hose in parallel for the longer narrower bed and then ran intersecting hose for the shorter/wider beds. I think if your bed is 6 feet or longer, there is enough room to run at least 3 hose in parallel. With shorter beds, you only need 2 hose segments and you get more support using the intersecting method.

Step 4: Cut Clear Plastic Cover to Fit Over the Hose

I used 4mm thick plastic for mine.

Step 5: Make Clips to Hold the Plastic to the Hose

Cut 2" pieces of irrigation hose and then cut a slit completely down one side of them. These will clip over the plastic and hose frame to secure the plastic in place. I only clipped them on one side of the hose so that I can easily fold the plastic back in warmer weather.