Today was a monumental day for the farm: we have (nearly) completed construction of our greenhouse, which greatly expands our ability to grow our own produce from seed. We’ve been working on it in fits and starts over the past three weeks, as weather and time have allowed, and are thrilled with how it turned out.
Not only can we grow more seedlings from seed, but we can grow them earlier too. Last year, we waited until late February (at the earliest) to get seeds in the ground, timing it so that they would hopefully avoid any late spring frosts. Now, we can start seeds in the greenhouse fully a month or more earlier, and set out seedlings in late February or early March, meaning earlier harvesting of many of our spring crops.
The video below goes through many of the main steps of building the greenhouse, but I’ll share them here too. Of course, there are many ways to go about greenhouse construction, including buying a kit, but this is what worked for us.
The style of greenhouse we wanted to build is a standard 12-foot width based on the dimensions of the building materials for the frame of the greenhouse (either PVC pipe or chain link fence top rail). There is no set-in-stone length, so we calculated the number of seedlings we wanted to be able to grow (around 2,000), and settled on a 12 x 12 foot area.
Before any construction began, the first step was to create a level foundation. We leveled the ground the best we could, then trenched as necessary to ensure that the foundation boards were level all the way around.
With the foundation in place, our next step was to erect the end wall bows. Each bow was made up of two pieces of 10-foot long PVC connected with a tee fitting to form a 20-foot long arch. With the end wall bows in place, we then framed out the walls with 2 x 4s. One side would eventually turn into the doorway, the other was there for general structural support.
We then returned to the “skeleton” of the greenhouse, assembling the remaining PVC. The”ribs” were spaced two feet apart along the “spine”.
When the glue was fully dry at all the PVC joints, we connected the spine to the end wall bows, and bent each rib into place, clamping it to the foundation board.
We then built the door from a clear corrugated roofing panel framed in with 2 x 4s. Next came the hipboards, which run the length of the greenhouse (at approximately hip height), and add some additional stability as well as a place to secure the greenhouse film.
After that, it was a matter of getting the film in place. We did the end walls first, securing the film along the end wall arches with wiggle wire, and at the bottom by putting a 1 x 4 over the plastic and securing it to the foundation boards. Pieces of a 1 x 4 ripped in half were used as trim around the door to secure the plastic there.
Finally, greenhouse film went up and over the skeleton, and was secured using wiggle wire along the end wall arches and each hipboard. All that remains is to create roll-up sides, which will enable us to roll the greenhouse film up to the hipboards for ventilation on warm days.
Plants are already moved in, and I’m sure hoping they’ll be happy and healthy in their new home, awaiting transplant day.