This post comes from the suburban farming duo Mike and Melissa Mearns of Rubberneck Farms, just outside of Seattle WA.
West of the Cascades, we are cursed with the late arrival of spring and early retreat of summer. This makes it difficult to grow certain long-season crops such as tomatoes and peppers. In order to grow these foods for our community, we need to extend our growing season and keep it economical. The solution: a hoophouse! The design: Well, we kind of made that up as we went along.
So, what is a hoophouse? Just as the name suggests, a hoophouse is made up of a series of hoops covered with a layer of heavy duty plastic to capture and retain heat. The plastic is stretched tight across the frame and fastened to the sides in such a fashion that the sides can still be rolled up for ventilation in hot weather. It’s as simple as that.
Along the north side of our property lays a very long gravel driveway, the last 30-40 feet of which sits in the sun for a majority of the day, no matter what time of year. This is where we pounded 2 foot rebar stakes into the ground to mount our PVC ribs. We built two walls out of 1x4s and attached them to either end of the hoophouse by fastening them to T-posts pounded into the ground. To hold the whole thing together, we ran a series of 1x2s down the length of the structure and screwed into the PVC ribs. The dimensions we chose for our hoophouse design were based upon the standard dimensions of the materials we purchased from the hardware store (read: minimal amount of cutting and measuring).
The tricky part was finding an inexpensive plastic to use on the walls and body of our hoophouse. It’s important to use a plastic translucent enough to allow light through but strong enough to last the season and take a beatin’. We went with the most economic and readily available choice: a very large roll of 6mil. painter’s plastic. Which brings us to the fun part: stretching one very large sheet of plastic across a structure 8.5ft tall and 16ft long. Once the plastic is up, it is stapled into all wooden surfaces while holding the plastic as taut as possible.
Generally, we found that our initial hoophouse design worked perfectly for us.
On average, the temperature inside our hoophouse stayed about 5-10 degrees warmer than outside. This allowed us to start seeds within the structure while temperatures were still dipping into the low 40’s at night; giving us a jumpstart on the growing season.
However, there is one important lesson we took from our hoophouse design last year: painter’s plastic does not hold up to one summer’s worth of UV rays. The first wind storm of early fall came in and literally tore the plastic off our hoophouse. When it came time to extend our hoophouse this year, we splurged on agricultural grade plastic (meant just for this purpose) and a set of poly-channels, which allow us to secure the plastic without puncturing the material.
All-in-all, there are several different designs and materials to use in building a hoophouse. You can build one quite easily for a couple hundred dollars or a couple thousand. It all depends on how fancy you want to make it. Here at Rubberneck Farms, we aren’t all that fancy.