Sometimes tunnel vision isn’t such a bad thing.
On a farm, for example. “High tunnel” farming, in fact, is a new, but good thing. Think of it as a tunnel-shaped greenhouse.
(Photo of Millsap Farms, by Nate Luke Photography for Farm Talk)
So what’s the big deal about that? In a high tunnel, you can grow crops in a place, or at a time of year, when those crops don’t normally grow. So folks in Missouri, for instance, can get fresh spinach and lettuce, carrots or kale all the way up to winter time – and no, you won’t see those plants outdoors in a Midwestern winter. As one farmer put it, in some areas a high tunnel means you can be a “four-season farmer.”
Now in case you’re wondering about this story, these tunnels are also described as “hoophouses”.
That’s because these tunnel farms are made up of big plastic (PVC from ethylene) or metal hoops – with enormous plastic sheets stretched over them. Underneath, there are rows and rows of plants growing under the “sheet.”
But while the hoops are important (they hold the whole thing up), if there wasn’t something to put over them (that clear plastic sheeting), there wouldn’t be anything growing underneath. That makes those polyethylene and polycarbonate plastics (used to make the sheets) mighty important. And in turn, the building blocks of those plastics – the petrochemicals ethylene and benzene (long transformed by chemical reactions in the lab, of course, by the time they cover over a high tunnel) – that makes those petrochemicals mighty important too.