Jumping Through Hoops

Lately I’ve beed busy installing a hoop house in the back garden. A hoop house will allow year round vegetable production, frost protection for sensitive crops like citrus and figs, and healthy recreation space in the colder winter months.

Each layer of hoop house skin shifts the indoor climate by one and a half agricultural growing zones. So my Sonoma hoop house (USDA zone 9a) will effectively simulate San Diego’s growing conditions (USDA zone 10b). If I ever decide to get aggressive I could double the plastic skin with an air gap and be able to garden in a virtual Hawaii.

In summer the structure may serve as a shade house to keep crops from bolting in extreme heat. This could also help conserve water during droughts. Special perforated cloth can be installed in lieu of the winter plastic skin as needed. Or vines can be trained up the framework to keep things cool while also bearing fruit.

And in an emergency situation the structure might just be pressed into service as a makeshift shelter. A hoop house is more likely to wiggle and bend a bit in an earthquake than collapse like a typical house. It’s also easier to twist back into functionality in a hurry.

I ordered a do-it-yourself kit months ago from a company in Shaker Heights, Ohio so I’m confident that the system that was designed to endure a Great Lakes winter will surpass my needs here in Northern California. Installation was repeatedly delayed by Covid restrictions, massive forest fires, highway closures, supply chain disruptions, and 107F/42C heat waves. But the components eventually arrived and progress is now underway.

Some years back I explored the possibility of adding on one small room to the existing house and determined it was going to be a $200,000 debt soaked multi year endeavor. Instead, I built a completely legal off grid garden shed that serves well enough as an occasional guest bedroom and home office. It does everything I need and was constructed on a cash basis without violating any rules. Sub rosa adaptation is my preferred option.

The new hoop house is another step along this same trajectory. According to county regulations various “temporary, portable, soft-skinned structures” are completely legal so long as they conform to certain parameters. There are height and size limits, setbacks from the property lines, and a prohibition on electricity and plumbing. There’s a subtle but legally significant distinction between a “greenhouse” and a “hoop house” and I’m determined to stay on the correct side of that line.

One of the complications of building a hoop house in my back garden involved the slope of the land. From one end of the structure to the other there’s a three foot drop in grade. Before I ordered the kit I reached out to the supplier and they provided photos from previous customers who had successfully built hoop houses on similar slopes. It required some adjustments, but it worked.

The highest point of the structure can’t be more than twelve feet tall by law. Due to the slope the top end of the hoop house is nine feet high while the bottom end is twelve. The roof ridge line is dead level, but the legs are incrementally longer as the ground falls away. Once the plastic skin goes up we’ll have to get creative about the little triangular sections at the bottom, but it’s all perfectly do-able.

The plan is to leave the plastic skin off for the majority of the year. There’s little risk of frost before mid November (with rare exceptions) or after late April (although there are freak events.) The skin will be used roughly from Thanksgiving to Easter. The shoulder seasons have lots of temperature swings so there’s going to need to be some adult supervision to keep the plants happy.

Even in winter when it’s cold outside a hoop house can get too hot and will require ventilation. The simplest method is to open doors and windows and/or roll up the plastic skin on the sides of the structure. But that requires active monitoring and consistent decisive action. And someone needs to remember to close things back up before the temperature drops again too.

Automated systems work well, but that necessitates special machinery and electricity which is verboten in my case. So I’ve discovered some clever passive mechanisms to manage some (if not all) the temperature and time sensitive operations.

Operable louvers placed at the top of each end of the hoop house can help vent the hottest air and promote cross ventilation. These louvers can then be opened and closed as the temperature rises and falls using wax cylinders. When the temperature hits a certain point the wax inside the cylinders expands and pushes the louvers open. When the temperature drops the wax contracts and pulls the louvers shut. It’s an elegant system and I’m curious to see how well it works once it’s up and running.

There are things I have some control over in life. And there are others that are beyond my abilities to do anything about. I have no power over the global economy, the present political environment, the regulatory process, massive forest fires, earthquakes… At times I think California is falling apart and it might be time to pack up and leave. But it’s a gorgeous place and it’s my home - at least for now.

I’ve traveled a great deal in my life and I’ve never been anywhere in the world that didn’t involve some kind of serious trade off or compromise. To quote Douglas Coupland, the patron saint of my own Generation X, “New Zealand gets nuked too.” This hoop house is one of the small household baby steps I can take to make myself and the people around me a tiny bit more secure. So I’m doing what I can where I already live. As my Sicilian grandmother used to say, Ciò che non ti uccide ti rende più forte. What doesn’t kill you makes you stronger.

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