The name “cranberry” derives from the Pilgrim name for the fruit, “craneberry”, so called because the small, pink blossoms that appear in the spring resemble the head and bill of a Sandhill crane. In addition to Massachusetts, the major growing areas for cranberries are New Jersey, Oregon, Washington, Wisconsin, and in the Canadian provinces of British Columbia and Quebec.

Cranberries are a unique fruit. They can only grow and survive under a very special combination of factors: they require an acid peat soil, an adequate fresh water supply, sand and a growing season that stretches from April to November. Contrary to popular belief, cranberries do not grow in water. Instead, they grow on vines in impermeable beds layered with sand, peat, gravel and clay. These beds, commonly known as “bogs,” were originally made by glacial deposits.

Cranberry vines are planted by gently pushing vine trimmings into a prepared bog that has been leveled and covered with a layer of sand. New plantings must grow for about three years before they will bear harvestable fruit. If properly cared for, the 6-8 inch tall plant will produce berries indefinitely. Modern management practices include weeding in the spring, fertilizing in the summer, pruning in the fall to keep the vines at their optimum length, and periodic re-sanding in the winter.

A complex water distribution system must irrigate the bogs in dry weather. This same system is also used to protect flower buds and the ripe berries from spring and fall frosts. Also, flooding is required during the fall harvest and throughout the winter months to minimize the effects of cold and wind damage.


On Nantucket, the Early Black variety of cranberries (small and black-red when ripe) are harvested during late September; the Howes variety (larger, oblong and medium-red when ripe) is picked from early October into November. Cranberries were individually handpicked until the early 1900’s, when the wooden cranberry scoop was developed. The cranberry scoop method of harvesting was faster, but it left a great number of berries on the vine and was very labor intensive. Since World War II, growers have used an assortment of mechanical pickers, including the Western picker and the Darlington picker. Tines (metal fingers) on these machines scoop underneath the berries and hold them, while the forward motion of the picker plucks them from the vine. The machines damage the vines less than the use of the scoop, but as much as twenty percent of the fruit can be bruised using this method.

Today, more efficient and less damaging mechanical techniques are used. During wet harvesting, a section of bog is flooded with a foot or so of water. A machine called a water reel beats the submerged vines with a series of horizontal paddles. This causes the naturally-buoyant cranberries to detach from the vines and float to the surface of the water. They are then corralled and pulled to the edge of the bog with floating wooden booms. The fruit is loaded into large dump trucks by a conveyor. Following washing and screening, the berries are shipped by tractor trailer to the mainland to be processed by fruit handlers.

Nantucket’s cranberries are processed in three steps. First, they are washed and blasted with a strong current of air to eliminate leaves, twigs, and other debris. Second, they are sorted using a Bailey Separator, where the berries drop vertically through a series of seven compartments. At each level they may either bounce over a four-inch high board into the “good berry” side of the machine or drop down to the next lower level. Firm (good) berries bounce; soft berries are overripe and will not. Those berries that are overripe will continue to drop until they reach the bottom of the sorter and are eventually discarded. The good berries are bagged and sent to freezer storage for future processing into juices, sauces, or relish.

Because wet harvesting causes the fruit’s protective wax coating to break down, only dry-picked cranberries are sold as fresh fruit. After they have gone through the same sorting routine as outlined for wet-harvested berries, dry-harvested berries are visually inspected for color and appearance and polished by soft brushes. They are then bagged and immediately sent to market.

The Foundation once was a member-grower of the Ocean Spray Cooperative.  It now sells its berries to Decas Cranberry. Decas supplies many food supply companies and is the second largest cranberry company in the world. It produces concentrate, sweetened dried berries, cranberry extract powders and oils, and markets fresh whole and sweetened dried cranberries.

It is possible for visitors to come and watch the harvesting of the Foundations cranberries at the Milestone Bog during the Cranberry Festival which is held on the Saturday of Columbus Day weekend in October.  For more information please click here.

Interesting Cranberry Facts

The Nantucket Conservation Foundation’s bogs can produce nearly 2 million pounds of cranberries a year!