A common misconception about cranberries is that they grow in water. At harvest time, beds are flooded for six to 48 hours to allow the plants to untangle and the berries to float to the top for easier gathering. In winter, flooding forms a protective barrier of ice to keep the plants from drying out. In spring, a bed may be flooded to protect growing plants from drying winds and to keep buds from opening too early. Some producers also flood in late fall or early spring to kill off fungus or pests. Frost is always a danger in low-lying marsh areas, where cold air can settle even in July and August, says Blake, who uses a sprinkler system to protect his plants.
During the growing months, April to October, constant vigilance is needed to keep insects at bay. As Blake puts it, “If you have a monoculture, you're going to have pests.” To keep close tabs on pest populations, he sweeps a special insect net over the vines, then checks the net to see what beneficial insects or pests are present, and in what numbers. Using target-specific pesticides (Bacillus thurengiensis for example), he can keep pests such as black-headed fireworm down to acceptable levels while not harming beneficials such as spiders. Blake uses an Integrated Pest Management program, using a combination of chemical, cultural and biological controls to keep losses from pest damage to an acceptable minimum.
Once harvested, the bad berries are separated out by machine, then discarded. Visual inspection and packing follow. A good yield is 22,000 kilograms per hectare. Blake estimates that 98 per cent of his crop is marketed as fresh fruit in the Maritimes, Quebec and Ontario, and the Eastern Seaboard. Some of it goes into Mrs. J's Preserves, a line developed and still managed by Blake's mother, June, and sold in the farm's gift shop.
For 17 years, Johnston's Cranberry Marsh in Ontario has been a major part of the Bala Cranberry Festival. In October 2000, Blake and Kate carried on the tradition in Aylesford, and nearly 1,000 people showed up. Last year's Bala Festival attracted close to 25,000 people, Blake says. With that kind of interest, the Johnstons are hoping the future for the Aylesford marsh will be just as rosy.
In his former career as a landscaper, Blake Johnston frequently incorporated plantings of cranberries in his designs. Their use as a ground cover “has been overlooked,” he says.
The key to success in growing cranberries, whether for food or ornamental purposes, is to create the conditions they prefer: a moist but well-drained substrate using sand and organic matter is essential, with a soil pH of between 4.0 and 5.5. The biggest difficulty for the backyard grower is finding cuttings to plant; most nurseries don't yet stock them, and cranberries do not propagate from seed. Cuttings can be divided into smaller segments, pressed down into a prepared bed and kept moist with regular watering.
Pest control is not usually an issue for home gardeners, other than removing weeds. If your plants receive adequate moisture and minimal nutrition, the plants should be able to resist the occasional predatory insect without substantial losses.
The most dangerous time for frost is at bloom and just before harvest. To protect against frost, mulch plants with evergreen boughs or burlap.