Expert offers tips to keep your garden growing into fall and winter
By Brenda Sullivan - ReminderNews
Colchester - posted Mon., Sep. 23, 2013
Gardeners in Connecticut are familiar with a short growing season – approximately from mid- to late-May to mid-October, when there’s usually a “killing” frost – combined with unpredictable weather in the summer that can make it challenging to get a satisfying yield from the typical backyard garden.
At a talk Sept. 19 at Cragin Memorial Library, plant science expert Martin Gent from the Connecticut Agricultural Experiment Station had some tips for meeting these challenges.
Over a more than 30-year period, Gent has experimented with different kinds of shelters that allow gardeners and farmers to begin planting earlier and continue to grow some kinds of vegetables into the fall, or even winter.
These shelters range from floating row covers to unheated greenhouses.
Audience members were surprised by some of Gent’s advice, which included combining row covers – spunbond polypropylene cloth – with a sprinkler system that mists the plants when temperatures drop at the end of the growing season.
Misting plants can serve a few protective functions. For example, it can cause a layer of ice to form on the outside cover, and therefore protect the plants underneath.
Misting (before temperatures drop below freezing) also can create a layer of ice on a plant’s exterior, forming a kind of insulation that keeps freezing temperatures from drawing moisture from the plant’s interior and killing it.
This method won’t work for all kinds of garden vegetables, however, so it’s best to do some research before trying it.
Gent noted that row covers are not recommended for use with fall plantings such as kale because in Connecticut there’s high humidity, which can promote fungal diseases.
He also noted that when trying to extend the growing season, don’t expect the same level of production. “It takes about three times longer to get a head of lettuce in the winter than during the summer,” he said.
As for getting started earlier in the year, Gent showed slides of his system for starting seedlings indoors, including the use of heating coils under flats (plastic trays for seedlings) laid out on benches. “Seeds germinate much faster at 70 degrees than at 60 degrees on a windowsill,” he said.
The flats are also loosely covered with plastic wrap to keep the seedlings moist.
He also suggested using common shop lights, fluorescent lights, hung about 1 and a half feet above the seedlings and warned not to keep the lights on 24/7, since most plants need even a period of darkness. About 16 hours of light is sufficient, he said.
The next step is to transfer those seedlings to what’s known as a cold frame – a low-lying, south-facing box whose sides are constructed so that the glass or plastic covering the box lies at a 45-degree angle.
Gent showed a slide of a cold frame he built with plywood and covered with a layer of greenhouse-grade (6 ml) plastic film and insulated with 1-inch rigid polyurethane board.
He pointed out a 4-inch drainage tube looped around the interior that was capped and filled with water. This device acts as a passive solar heater – the water stores warmth from the sun during the day and releases that heat at night.
Gent also noted that it’s important to uncover or “vent” plants during the day – whether they’re in a cold frame or an unheated greenhouse – or risk “cooking” them in the sun’s heat. Plants that are covered in the spring won’t be pollinated, and unpollinted plants don’t produce fruits and vegetables.
Gent also showed and discussed the pros and cons of covered “high tunnels,” and greenhouses without concrete foundations, and various experiments with the timing of covering plants and how that affected production.
To learn more about resources offered by the Connecticut Agricultural Experiment Station, visit the website http://www.ct.gov/caes/site/default.asp. You can also contact Martin Gent with your questions at Martin.Gent@ct.gov or 203-974-8489.