Cranberries play an important role in late-year festivities like Thanksgiving and Christmas. In the Tri-town and surrounding Southeastern Massachusetts, cranberry bogs are a defining feature of the land, culture, and history of the region. We pass them on the road, we hike past them in the summer, we visit local farms in the fall, then we eat them, by can or fresh from the store. One time of year lacks public focus and knowledge; what happens to them in the winter? What happens to the cranberry bogs during the freezing cold? Is anything done with them? Are they just left until the next harvest? What preparations must be done?
There is work to be done after harvest and before the coming of freezing temperatures. Cranberry plants do need to be protected from winter winds, with the bogs themselves entering a period of “dormancy” during the winter months. Generally, all bogs are flooded in some regard. The water, often turning to ice, protects plants from harsh winds. A layer of ice also acts as additional insulation. Winter winds can lead to “desiccation,” or the drying out of the plant. Farmers monitor the ice through the winter and adjust the water levels to maintain the right balance and not bring harm or suffocation to the plants. Fungal diseases can also develop under prolonged wet conditions, making careful water management crucial. Another major concern is the timing of the thaw. If winter protection is removed too early, a late-season frost could damage the developing buds, reducing the yield for the next harvest. Local farmers must carefully and constantly monitor weather conditions to ensure they drain the bogs at the optimal time.
Should a sufficient layer of ice form above the plants, Sippican Land Trust’s Alan Harris says, “I do know they often flood the bogs during a cold snap for frost protection and in the hope that it will freeze solid enough for long enough that they can spread a layer of sand on the bogs.” He continued, “the sand improves the vine growth and used to be more regularly scheduled but winters have been less reliable.” Sanding is a common practice across bogs, though Harris states it is less reliable now, predominantly due to higher temperatures and a lack of ice build-up. When temperatures rise and the ice in the bogs melts, the sand spread across the ice settles into the vines and acts as nutrients to promote growth. It also prevents pests by burying insect eggs and improves the plants’ health and condition coming into the spring.
Harris also mentioned another plight to the local bogs – muskrats. “The dikes often host muskrat burrows (not wanted by the farmer) and freeze-thaw cycles in the winter can lead to these collapsing. So, they need to be filled and maintained” he said. The muskrats are complemented by mice and voles who are also known to frequent bogs. Through the drain and fill cycle of the winter, farmers must also be vigilant for these habitats.
Many bogs in the Tri-town are accessible through hiking trails. While they seem dormant and frozen in time, there is a lot of work that goes into achieving this delicate balance. As winter gives way to spring, the water is gradually drained, and the vines come back to life, ready to begin another growing season. The work of cranberry farmers doesn’t stop with the harvest; it is a year-round effort to maintain the health of their bogs. Their careful winter preparations ensure we have juice for summer drinks and our end-of-year feasts.
By Sam Bishop