Fall 2022 - Greenhouse tunnel project
We spent a good portion of Fall constructing a 24' x 30' greenhouse tunnel. The hoop house sits at the southeast corner of the property and will provide a year-round covered growing space. Many thanks to the friends and neighbors who helped clear and level the area where the tunnel was constructed and pitched in with construction (many hands makes light work) . A special thanks goes to our good friend Ben Kates for spending many long weekends working hard to help us get this finished before the cold weather settled in. We're very excited to expand our growing season through the winter and to increase yields of warmer weather crops in the summer.
The photos below show some of the stages of construction. We'll add additional photos as we make more improvements and plant more crops.
After leveling the area, posts were driven about 20" into the ground on each side at every five feet. This forms the footing for the hoop structure
Each hoop is constructed from four interconnecting pieces, fastened by self-tapping screws.
Each hoop is set into a pair of ground posts (with a little effort).
Preparing for purlins
Finding the centers of the hoops in order to run the purlins.
The tunnel is about 12' tall.
Three purlins run the length of the hoop house to provide support to the structure. A lot of time was spent on ladders connecting the purlins at each spot they cross a hoop. At shoulder height you can see the first run of wiggle wire channel (used to attach greenhouse plastic). I later removed this and used lumber to create a 'shoulder-board' and provide more support - and then attached the channel to the wood.
Baseboards and shoulder boards
Wood framing was added around the base of the greenhouse to minimize soil washout and further stabilize the structure. The wooden shoulder boards are also visible here. Shoulder boards are sometimes called hip boards depending on how high they're placed. The top plastic will connect to the sides of the greenhouse at this point.
End wall framing
Both ends have full end wall plastic. The front side has a double door and the rear has a single door. I used pressure treated 2x4's for the framing and sort of made up the design/plan. Seems pretty stable for now.
End wall plastic
The rear end wall plastic is hung and attached along the curve of the hoop using wiggle wire. You can see the wiggle wire channel on the shoulder boards in the foreground. The plastic is pulled into the channel and an undulated, plastic-coated wire is used to keep it place using pressure against the sides of the channel.
The top plastic was pulled across the top with one person on a ladder on each side and one person in the middle pulling the plastic with a rope. We put it on with the wrong orientation the first time. Oops.
Both ends and the top plastic are secured using wiggle wire and channel. You can see the flap of plastic hanging from the shoulder board to the ground with a long bar sitting on top. These will become the roll-up sides.
Two glass storm doors are added to the front and one to the rear. The front doors were not a double door set (cheaper to just buy two doors) and a lot of tweaking was needed to get the doors to close and latch.
Roll up sides
Each side can roll up using a hand crank to allow cross ventilation as needed. You can also see the black strapping that is attached to the shoulder board between each hoop. These straps go over the top of the tunnel and connect to the other side to keep the top plastic from billowing in the wind.
Rope is attached from the baseboard to the shoulder board to keep the wind from catching the sides and pulling them up. This method still allows for the sides to roll up with the wall plastic sitting between the hoops and the rope
Rain gutters were run on each side for the length of the tunnel and attached to the shoulder board lumber. This makes it easier to avoid washout at the sides of the tunnel and to harvest rain water for future use.
Each gutter feeds two 55-gallon rain barrels which gives us more than 200 gallons of rain water to use to irrigate the crops in the tunnel.
We continue to use a no-dig method where initial soil fertility is built on top of the existing topsoil and eventually mixes with lower strata through natural means (water movement and soil biology). Cardboard acts as a temporary weed barrier that keeps weed pressure off as it disintegrates and gives new beds a head start.
Compost is used to make permanent beds with wood chips used in pathways. Wood chips help suppress weeds and also help conserve water at the edges of beds. A deep mulch (compost) system can drastically reduce water usage and provides for a high level of organic material in garden beds.
A winter workspace
We'll be keeping a section of the greenhouse (in the middle near the front) cleared to provide for seedling starts and hardening as well as a small workspace. Above we are hanging green tomatoes to see if we can get a few more to ripen.
More photos to come as the greenhouse adventure continues.