Extension News: November 2005 Archives

When I go out to the chicken coop early every morning, I expect to let our 11 hens out, give them fresh water and food, check for eggs, and return to the house. Somehow it never works out that way. After completing these chores, I turn to leave and inevitably see something in my nearby garden that needs to be moved, transplanted, watered, fertilized, divided, cleaned up, or just plain admired. If that isn’t enough, I now have a hoophouse calling my name.

What’s a hoophouse? I think of it as a greenhouse on training wheels. Hoophouses—also known as “high tunnels”—are enclosed growing spaces that don’t have glass windows, heat, or ventilation fans.

My husband, John, and son, Christopher, built our hoophouse over two or three weekends, using tubular metal or PVC hoops set in the ground, stretching heavy, clear plastic sheeting over the frame and adding plywood doors into both ends to allow entrance and to help ventilate the space. The frame is 16 feet wide by 20 long, and tall enough to walk in comfortably, with plastic sides that can be raised to let in more air or lowered to keep out wind and insect or animal pests. Our hoophouse, purchased as a kit, cost about $500.

Inside I have a potting bench and slatted-top tables on the left; on the right, I have a 3-foot wide planting bed in the ground, where I plant heat-loving crops, such as tomatoes, eggplant, and peppers, which prosper all summer until the first hard frost turns them to mush.

Some articles by Dr. Otho Wells, UNH Cooperative Extension’s former vegetable specialist and a pioneer in season-extending technology for our region, first got me interested in hoophouse gardening. I’ve also taken a lot of information and inspiration from Eliot Coleman’s Four Season Gardening.

During my first summer with a hoophouse, I found it especially useful for growing tomatoes and other hardy crops free from disease. The Brandywine tomatoes were delicious, without a spot of early blight.  I got more eggplants and green peppers than from the outside garden.  Here in Zone 4, the shelter of a hoophouse gives my tender heat-loving plants a head start and prolongs their season a few weeks in the fall.

Now, in early November, I’m still harvesting bok choy, ‘High Density’ winter lettuce, mizuna (an Asian salad and braising green) and Italian parsley, all started in plastic cells in August and transplanted into the hoophouse bed. You could also have kale, chard, spinach, mustard and other hardy greens, as long as you have fully grown plants by the time frost and cold nights arrive. When temperatures dip below 50° F, I cover the plants with a layer or two of polyester row covers, available at most garden centers.

The rest of my plantable space overflows with hardy miniature roses, an ‘Autumn Sunset’ climbing rose that spent the summer in a pot, and lots of violas and pansies that somehow found their way inside. So as color disappears from my garden, I can still go inside to see those delightful harbingers of spring. 

Today, I left the chicken coop, where the thermometer registered a cold 40°, and went to my hoophouse, where it was 50°. It felt warmer though, because there was no wind, and the sun was shining—always a psychological boost this time of year! I left the snug, sunny hoophouse and shivered my way back into the house.

Heading into my second winter of hoophouse gardening, I can pass along a few lessons learned:

• When cold weather sets in, polyester row covers protect crops as well as glass storm windows, and don’t need to be lifted if the temperature suddenly rises.

• Trying to overwinter tropicals, such as callibrochoa or zonal geraniums, takes more heat than a hoophouse can produce.

• Although edible greens will stop growing in December, you can harvest leaves throughout the winter. As long as you don’t pull plants out by the roots or destroy their growing tips, the roots will begin to regenerate and start producing new leaves again in March— perhaps even sooner in Zones 5 or 6.  We had succulent Buttercrunch lettuce from mid-March to late May from plants that stopped growing during the coldest part of winter. Mache and miner’s lettuce did well also.

Next year I may expand my plantable space so I can include carrots and beets to harvest all winter.  This will mean cultivating soil that currently sits under my work stations, but I think we can work it out.
 
Early last month, on a wet, windy Saturday, my 2 ½-year-old grandson Oscar came into the hoophouse in his rain jacket and little red boots, and, as only a child unburdened by grown-up clichés can do, proclaimed, “No wind, no rain. This must be a garden with a roof on it!”

By Helen Downing, UNH Cooperative Extension Master Gardener