Cranberry Bogs: How are cranberries harvested?

Discover the farming methods used to cultivate one of the world’s most versatile fruits

Cranberries are cultivated for juices, jams, sauces and other edible products in Europe, across North America and in some parts of South America. Some natural eating advocates claim that the little red fruit is one of the healthiest foods on the planet, partly due to its antioxidant properties.

Bogs are the natural habitat of cranberries. These wetlands have developed on poorly drained glacial deposits. Because of these conditions, bogs have a high water table and the ground can be saturated.

Many bogs are a source of peat moss, which often covers a large proportion of a bog’s surface area. This moss decomposes slowly due to the wet conditions and causes the water around it to be relatively acidic.

Few plants are able to tolerate these conditions. Yet cranberries flourish in bogs because they are shallow-rooted, tolerant of flooding and may interact with mycorrhizal fungi to access the limited nutrients in the soil. Above ground, a cranberry plant produces thin, woody runners that spread across the surface and may live for decades.

The combination of this resilience and the cranberry’s edible fruits make it an excellent crop. Commercially, cranberries are grown in specially prepared beds in boggy areas that are close to water sources such as ponds and reservoirs. The plants are cultivated on a bed of sand that is laid on top of the peat to stimulate growth and keep weeds down. In winter, the bed is flooded to protect the dormant stems from frost damage. After the beds are drained again in the spring, the flowers appear. If these are fertilised they will produce the berries, which start out white and then turn red throughout the summer and autumn.

 During Thanksgiving and Christmas, the berries are harvested, processed and packaged just in time to add a sweet touch to turkey dinners.  It’s estimated that Americans consume over 5 million gallons of cranberry sauce every holiday season!

Harvesting cranberries

Most cranberries are ‘wet harvested’. When the berries have ripened in late autumn, beds that were flooded the winter before are flooded again to a depth of around 45 centimetres. A special harvester is then driven through the bog to dislodge the berries from the plants. The loose berries float to the surface because of tiny air-filled spaces inside each one. Farm workers steer floating mats of berries towards an elevator that deposits them in a truck for transport. ‘Dry harvested’ cranberries are plucked off the stems by a machine and automatically bagged in sacks to be sold as fresh fruit.

This article was originally published in How It Works issue 103, written by Mike Simpson

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