Building a hoophouse from a kit
"Can you believe we built this?" I ask R on a regular basis, using the term “we” rather loosely, as you will see in the time lapse videos I made during the construction program. But it is true that we assembled and erected a 20×48′ unheated greenhouse mostly with our own four hands. And every time I open the doors, which I built, it is still a marvel that it is done. Done, by the way, is one of my favorite words in the English language.
Why a hoophouse?
- I like my veg fresh, not frozen, not limp from a too-long semi-truck shipment from California or Mexico. I like my veg without crap sprayed on them.I like variety in my veg, stuff you can’t buy from the store at any price. Long-time readers might remember my previous experiments with winter gardening under plastic. Short version: it works. I knew I wanted more space, so a hoop house has long been part of the master plan. But we ran out of momentum and cash last year, so I improvised some low tunnels. We got some nice winter greens out of them until the snows collapsed the crap 12 gauge wire hoops I made from the stoutest stuff I could find locally. Come to find out they sell 9 gauge wire by the pound from the back of the warehouse, but that is less than useful information now. And tromping through the snow to the kale patch made harvesting un-fun. Having satisfied myself that growing under cover would work here as well, we decided to go ahead with a more snow worthy growing environment.
- We need a barn-part 1. Our garage was full of feed, a tractor, garden and orchard tools. Behind the house, the boneyard of useful spare stuff was a Clampett family paradise. The square footage we could get from the hoophouse is about the most cost-effective we could find.
- We need a barn-part 2. The poultry are here to stay. Their coop is plenty winter worthy, for them. But who wants to haul bedding, feed, water through the rain, snow and mud all winter? Harvey Ussery’s model of housing the chooks in the hoophouse makes so much sense for us, even if we aren’t raising worms. The birds can go out in clement weather, but have everything they need inside, with plenty of room to run around out of the weather.
- We want a sheltered place to go out of the house to beat the cabin fever. Our house is 1000 square feet. I am pretty much here 24/7. There is no functional "third place" open in the winter to escape to (cue up Toby Keith’s I Love This Bar). It’s cold and dark here in December. Can you say seasonal-affective disorder symptoms? Sometimes an hour in the bright light is a huge mood boost.
How are we going to heat it?
We aren’t. First, by definition, a greenhouse is heated. A hoophouse or high tunnel is just a covered space without active climate control. Our main goal is winter veg, not frost-tender plants. Everything I want to grow or shelter can do just fine without heat, so heating would be an unnecessary expense. We are seeing 25 degree differentials between our porch and the hoophouse at mid-day, even though we haven’t really battened down all the hatches yet. When the plants need additional protection, I will put some row cover fabric over the whole growing area. Because our day-to-night temperatures in the spring and summer routinely go up by 40 degrees, we opted for roll-up sides to improve the daytime ventilation in all but the coldest months.
BTW the clouds are amazing to watch this time lapse video.
How did we do it?
We bought a kit from Growers’ Supply out of Iowa. I looked for a closer supplier, but even with the ridiculous freight costs to get anything to our place 60 miles off the interstate, their product and support made the most sense for us. The sales rep customized a kit for us that added the roll-up doors to what they called a “straight-sided cold frame” in their catalog. It was hard to believe that entire unit fit onto an 8’ pallet only about a foot high.
The original plan was to till the site, then level, then start with a clean building site. That is the preferred method, by far. But opportunity struck in the form of our friend Courtney asking if he could bring his backhoe over to clean out his irrigation ditch (he has an easement through our property). "Oh Courtney…could you dig a trench over here, while you are digging?" And thus I got my redneck root cellar down the center of the hoophouse, but then we just had to get it covered. You’ll see in the video that we didn’t get the plywood to cover the trench until the second work day, not the brightest move but nobody got hurt.
Then it started raining, which put the whole project behind schedule. Talk about monsoons, the rain went on for weeks. We stopped working more times than I can count because of lightning. I arranged for the son of a friend to help us for a few days (thanks Celtin!) and we just got down to. It went pretty smoothly, especially once the ground posts were driven in. Torrey soil is notorious for its rocks. Courtney told us that most fences around here have their postholes dug by backhoe, because you are too likely to break an auger. Once again, after driving 26 posts, we realized we got lucky with this parcel, because they all went in straight, or straighter than you can count on around here.
The order of ceremonies is to set the posts, assemble the ribs and purlins (long cross-pieces connecting the ribs), then complete the endwalls. I saw a photo of endwalls that I liked, and that’s what we built. That was probably the hardest part, because none of us are carpenters. R and I pulled the plastic up the endwalls ourselves, learning how to work with the wiggle wire. We deviated from the instructions on this step. The standard procedure is to stretch the plastic over an end rib, then screw down the wiggle wire channel over the sheet to hold the endwall cover in place. But our salesman had suggested using a double layer of wiggle wire when we installed the main cover as added protection in the wind, so we bought extra. We did a test to see if we could secure the endwall plastic with one wire, then layer the main plastic into the channel with a second wire. It all fit, so that’s what we did. When it comes time to change out the plastic (warrantied for four years), we won’t have to remove the channel, just the wiggle wire.
Thanks to a drawn-out planning phase, in which I made an obsessively detailed Gantt chart and massive shopping lists (mostly for the lumber that was not included in the kit), the process went pretty smoothly (although I did turn off the camera at one point during the endwall phase because I was getting aggravated with our lack of construction knowledge; we eventually figured it out). The scariest step was pulling the 50×40’ sheet of plastic up and over the hoophouse. Did I mention that the wind blows in Torrey, a lot? Like all the time? And that the monsoons wouldn’t quit? We watched the weather, hoped, worried, and when it finally was time it was over in a flash. This was in large measure thanks to our friends Dayanna, Susan, Tammie, John, Ed and Sarah, along with some tennis balls and duct tape. Somewhere on the Internet, I read how to first wrap the plastic around a tennis ball, then tying a slip knot, over the plastic around the ball. The bulk of the ball secured knot from slipping as we pulled the plastic, which worked incredibly well at distributing the tension across the sheet. My little innovation was to mark the center point of each end of the sheet with some tape. As the sheet rose up and over the frame we lined up the flags with the middle purlin to make sure the whole sheet was centered on the structure. After a quick briefing on the plan, three people pulled their ropes and the sheet sailed right over without even a gust of wind. Everyone acted as weights just in case the wind picked up while R wiggle-wired his way down the windward side, then the leeward, and it was done! Crack open some sparkling apple juice, as it was far to early to celebrate with the hard cider.
Actually, it was almost done. We assembled the roll-up doors after everyone left. The lumberyard couldn’t get the plywood for the doors, so that stalled us for a while. Scott and Mary demonstrated their mad house-building skills to show us how to hang the doors. R got the Grillo going (note to R: we need to finish the rotary plow video) and tilled the soil. We laid down landscape fabric on the north side, then a bunch of pallets to store stuff off the ground. The chicken pen is next, with repurposed materials saved from other projects.
I planted the beds on September 17, even before the doors went up and as early as I could, but really too late to get full production. Even so, we had our first arugula salad on November 5. I put more seeds down, things like mache and spinach that will eventually germinate no matter how cold, and by February, we should be able to supply nearly all of our greens.
Added bonus: we can park both cars in the garage now. The north side of the bunkhouse is almost cleared of the pots, tools and bags of sand and other detritus of our projects. There are twelve bales of hay for the goats under cover. Coolers full of potatoes are resting in the cool of the redneck root cellar trench. Once we get some gravel on the thresholds and the chickens installed, we will be ready for winter. Give me some yard food like fresh eggs and greens and potatoes collected from the root cellar, and a pile of wood for the stove, and I won’t care how long it snows.
Don’t quote me on that if it’s still snowing at the end of March.