Cranberries grow on low, running vines in specialized fields called bogs. These are carefully managed wetlands that provide the acidic, sandy environment the plants need. The harvest season typically begins in mid-September and lasts through early November, when the ripe berries turn deep red. Collecting these fruits utilizes two distinct techniques, each tailored to the final destination of the crop.
Understanding the Need for Two Methods
The choice of harvesting method depends on the intended market use for the cranberries. Berries destined for fresh fruit sales, like those in grocery stores, must be collected in pristine condition to avoid bruising. This requires the gentler, less common dry harvest method.
The vast majority of the crop is gathered using the wet harvest process, as these berries are destined for processed goods like juices, sauces, and dried cranberries. Since the fruit will be cleaned and processed immediately, minor damage during a water-based harvest is acceptable. This wet method is possible because each cranberry contains four small air pockets inside its center. These air-filled chambers cause the berries to float readily once separated from the vine.
The Dry Harvest Process
The dry harvest is carried out before any flooding occurs. The vines must be completely dry, which can sometimes delay the process due to dew or rain. Only a small fraction of the total cranberry crop, typically less than 10%, is harvested this way.
Specialized mechanical pickers, sometimes called walk-behind harvesters, gently comb the berries from the vines. These machines use metal tines or reels to strip the fruit from the runners, depositing the collected berries into burlap bags or wooden boxes. The filled containers are then carefully removed from the bog using tractors to minimize disturbance to the vines. After collection, the berries are taken to a receiving station where they are graded, with the firmest fruit distinguished by its ability to bounce.
The Wet Harvest Process
The wet harvest is the high-volume method responsible for collecting over 90% of the commercial cranberry crop. The process begins by flooding the bog, typically with 6 to 18 inches of water, usually the night before the harvest. The water level must be high enough to fully submerge the vines.
The next step uses specialized machinery called water reels, which are often nicknamed “egg-beaters” due to their rotating action. These self-propelled machines are driven through the flooded bog, and their spinning paddle wheels gently churn the water. This agitation is sufficient to dislodge the ripe cranberries from their vines, causing the detached fruit to immediately float to the surface.
Once floating, the berries create a dense, vibrant red layer on the water’s surface. Workers use large, floating barriers called booms, made of plastic or wood, to corral the berries. These booms push the mass of floating fruit toward a central collection point at the edge of the bog.
From the collection point, the cranberries are quickly removed from the water to prevent spoilage. This is accomplished using either a conveyor belt that lifts the berries out of the water or a large vacuum pump that sucks the fruit directly into waiting trucks. The efficiency of this water-based method allows an entire bog to be harvested in a fraction of the time compared to the dry method, making it the preferred technique for supplying processing facilities.