I have a “love-hate” relationship with this time of year. The days grow shorter, and then daylight really takes a hit when we return to Standard Time. It’s hard to believe that shaving off one hour of daylight can make such a big difference, but it does.
Add the fact that we are racing towards the shortest day of year (the winter solstice on Dec. 21), and the light fading so quickly puts a real crimp on all the things you want to get accomplished outside.
A positive note is the pace of life and the types of activities change as well. As much as I love gardening and the optimism for all things green in our yardscape each year, I find I can get too much of even that great thing. Just about the time I get tired of all the things that go along with keeping a yard in good shape and a garden productive, it’s time to take a break for the winter.
But don’t let me fool you. Even now, I’m missing some of the gardening activities I enjoy so much. There is a bit of wistfulness that comes along when the season ends without getting some of the things done I hoped to back when I had boundless enthusiasm in early spring.
There’s even a greater reason I’m sorry the season has come to a close. Simply put, there is no substitute for the fresh-grown veggies and herbs we enjoy in the warm months. Maggie has become quite skilled in preparing two of my favorite summer dishes: Caprese salad (as well as bruschetta) and Asian spring rolls. These dishes offer incomparable taste due in large part to their fresh harvested produce. For the salad and bruschetta, ripe tomatoes and plentiful basil, combined with fresh mozzarella cheese, olive oil and balsamic vinegar, combine to create a healthy, light and vibrant meal that is simple and satisfying. As for the spring rolls, they are a real highlight. Wrapped in rice paper I purchased online from an Asian market, they are filled with thinly sliced cucumber, soft lettuce, mint from our garden, basil, cilantro and shredded carrots. Add a pinch of cooked rice noodles and some fried ground pork or shrimp and you’ll have a fresh and tasty party in your mouth. In fact, I instantly developed a regular craving and enjoy having them weekly during the growing season.
So, when the fresh ingredients for these dishes are no longer readily available, it’s a culinary “bummer.” I suspect that you have your own list of favorite dishes that are heavily dependent on the availability of a fresh harvest.
So, what’s a culinary gardener to do? Time travel, that’s what! While it’s not actually possible (at least as far as we presently know) to time travel, we can extend the growing season by getting our growing spaces warmer faster in the spring and keeping them warmer longer into the fall than they would naturally be. Practices related to this is known as “season extension.”
In fact, this was the topic of Michael Caron’s recent presentation hosted by the Master Gardeners. Last Wednesday night, Mr. Caron gave us some great insights into the world of greenhouses and hoop houses (also known as high tunnels). He knows a thing or two about this, having both worked in the greenhouse tomato industry, as is a USU Horticultural Extension agent at the Thanksgiving Point Institute.
To start, let’s define some terms. While the general goal is to be able to extend seasons so you can grow plants and vegetables earlier and longer, the methods to do so vary widely. We’ll limit our conversation to greenhouses and hoop houses or high tunnels.
In the strictest sense, a greenhouse is a conditioned, non-passive structure. This means it has heating and cooling that requires active systems to boost heating when needed and to quickly exhaust heat when temperatures spike. Greenhouses allow production or plant-starting year-round, usually on racks and not in the ground. As you can imagine, there are significant associated operating costs.
Hoop houses or high tunnels, on the other hand, tend to be operated as a more passive structure with crops growing in the soil. They are not typically cooled; rather, they are used to capture heat from the soil and radiate it back slowly during the night. Cooling is generally accomplished by passive venting or rolling up the lower portions of the sidewalls. Because heating is from capturing the warmth of the sun, high tunnel production is usually a three-season venture, with the winter being fallow.
You may ask, “which one is better?” It depends on what you want to grow, how much time and money you want to spend, and how much produce you want to harvest. Here’s why.
Greenhouses can be quite productive, but as Caron puts it, “having a greenhouse is like having a daycare.” You need to constantly tend it. Watering, fertilizing, ongoing pesticide applications, and rotation of plant locations are all part of the experience. Having the greenhouse gives you lots of growing options, but it takes commensurate labor and attention to pull it off. If you are hoping to make money with an active small greenhouse, you will be disappointed. It’s fine as a great hobby, but it takes very large operations, run year-round, to get the economics right. That’s why you’ll see the size of commercial greenhouse operations in the 20-acre range.
Greenhouses heat up and cool off rapidly. The exterior panels are meant to let light and accompanying heat quickly transmit into the interior of the structure. That’s generally good during the day in the winter when heat is needed. However, heat can spike, even midwinter, to a point where it’s fatal to the plants. That’s why there has to be automatic vents, or a vent operator — that would be you! The same low insulating properties that allow light and heat to quickly enter the greenhouse during the day now work against you as heat is lost equally as fast when the temperatures drop outside after sundown.
To offset this, some have gone to using the greenhouse in a more passive manner as you would a hoop house and limiting the amount of growing seasons. Some greenhouse “die-hards” grow year-round by insulating the north side and installing heat retention movable curtains on the south (sunward) face that are lowered after the sun goes down. Additionally, heat is collected and released back slowly using sizable heat sinks such as containers of water, stone gravel or concrete mass.
After hearing Mr. Caron’s presentation, my leanings are toward a high tunnel. First, the economics are very good. Because there are less structural elements included in a high tunnel, they cost less. Their simplicity also lends itself to the construction skills of more people. Second, they are built directly on the growing plot that will be inside. The size of the end panels allow easy access and can be made in such a way that tillers and even compact tractors can be brought in. Properly constructed, they are highly wind-resistant (an important consideration around here). This approach also has a heat sink automatically built in — the soil itself. When it comes to growing plants, the soil temperature is most critical, with the air just above the soil surface being a close second. Moist soil can hold an impressive amount of heat and costs very little. Pest control in a high tunnel is also less intense as the interior is allowed to freeze for the winter.
Lastly, the films that are used on high tunnels diffuse light well — a very desirable property for growing plants. Think of the light on a cloudy day with no direct shadows. Plants love it, and that’s what a properly outfitted high tunnel will provide.
If you’d like to further explore whether a greenhouse or high tunnel makes sense for you, here’s a couple of resources for you. Visit tunnel.usu.edu. If you’re really wanting to dig in, you can search online for “Greenhouses for Homeowners and Gardeners.” This is a 200-plus page resource that covers it all.
So, if the natural growing season is what ails you, and you’d like to enjoy fresh produce earlier and later in the season, a hoop house or greenhouse may be just what the doctor ordered.
Jay Cooper can be contacted at email@example.com, or you can visit his channel at youtube.com/dirtfarmerjay for videos on the hands-on life of gardening, shop and home skills, culinary arts and landscaping.