Cranberries are harvested in two main ways: dry harvesting for the fresh berries you see in bags at the store, and wet harvesting for the berries that become juice, sauce, and dried cranberries.

Dry harvesting (fresh berries)

Dry harvesting is the method used for high-quality fresh cranberries sold whole. It keeps the fruit drier and less bruised, which is important for shelf life and appearance.

  • Farmers use walkā€‘behind mechanical pickers that look a bit like small lawnmowers to gently comb berries off the low vines.
  • The berries are collected into burlap bags or bins as the machine moves along the bog.
  • Bog vehicles or even helicopters may haul these bags out of the field to a receiving station.
  • At the plant, berries are graded, checked for color, and sometimes ā€œbounce testedā€ because soft or damaged berries will not bounce.

Wet harvesting (flooded bogs)

Wet harvesting is the visually famous ā€œred lakeā€ method and accounts for more than 90% of the crop, mainly for processing into juices, sauces, and sweetened dried cranberries.

  • Growers flood the cranberry bog with about 18ā€“24 inches of water around harvest time in fall, once berries have turned deep red.
  • Cranberries have tiny air pockets inside, so they float when loosened from the vines.
  • Special machines called water reels or ā€œeggā€‘beatersā€ churn the water, knocking the fruit free so it rises to the surface.
  • Farmers then pull floating booms (long floating barriers) around the berries, corralling them into a tight cluster.
  • Conveyors or pumps lift the corralled berries out of the water into trucks, which take them to processing plants for cleaning and further use.

Seasonal timing and conditions

Cranberry harvest links closely to cool autumn weather.

  • In many growing regions like Quebec and the U.S. Northeast, harvest runs roughly from late September to late October.
  • Bogs may also be flooded in winter (separate from harvest) to protect buds from cold, then drained for spring and summer growth before being flooded again for wet harvest.

TL;DR: Cranberries are harvested either by dry picking with walkā€‘behind machines for fresh fruit, or by flooding bogs so the buoyant berries float, then corralling and pumping them out for juices and processed products.

Information gathered from public forums or data available on the internet and portrayed here.