by Gary Mount
In the late fall, much of the outdoor world that I am in touch with every day changes dramatically. Some things slow way down-fruit trees, berry bushes, weeds (thank goodness) and some things stop – vegetables and ornamentals. But regardless, the color green is gone. No longer can I see the daily miracle of plant growth, of fruiting and vegetable production, of getting ready for the next year’s cycle. All that just stops. And so my thoughts turn to the greenhouse.
Terhune’s greenhouse is not that big. Just three years ago we doubled its size to 5,000 square feet, but that’s still small as greenhouses go. However, it is a very active place. Starting in September and October, we plant hundreds of Freesia bulbs. These wonderful looking things grow slowly all fall and winter (55 degrees F). They bloom in January and February. Their blooms, all in a row on the stem, are the most amazing colors! You can see we are planning for our winter pick-me-up already, but that’s getting ahead of my story.
Some time this fall, after the frantic apple harvest and pumpkin season, but before it gets too cold (remember the freesia), we have to recover the greenhouse. We use a double layer of poly, stretched over the greenhouse frame and fastened at the edges. The existing plastic has been on for three years – about the limit. Ultra-violet radiation from the sun turns the plastic cloudy , thus reducing the amount of sunlight that can pass through. UV also weakens the poly and makes it more likely to tear during a windstorm. In the winter that would mean the end of the freesias.
The trick of recovering is to find a calm day, warm enough so that the plants inside don’t suffer, and then work like heck. Whatever is taken off has to get replaced by the end of the day. Cold temperatures at night would ruin everything inside.
Our greenhouse is two bays wide. Each bay is covered by two sheets of poly 28 feet by 100 feet. Each double layer is fastened securely around the edges and then attached to a small fan which blows air into the space between the layers. This creates a taunt air pillow which keeps the plastic from flapping in the wind and also provides insulation as well.
Hopefully, if the recovery goes well, we can start on our next crop. Although freesia, cyclamen and later some spring bulbs are in the greenhouse all winter, there is lots of space for something else – lettuce!
We started with lettuce last winter – red leaf, green leaf, Boston and romaine. 55 degrees turns out to be just right for lettuce as well as the freesia. We plant one crop after another – seeding and re-seeding all winter long. Each crop takes 8 to 12 weeks. We then pick it, sell it and start again. I stay happy – having a crop actively growing – until life on the farm outside begins again in the spring.