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Cranberry harvest: flooded bogs turn red

October

Every fall, cranberry growers in southeastern Massachusetts flood their bogs and churn the water with paddle-wheel beaters called water reels to shake ripe berries loose from the vines. Because each cranberry holds tiny pockets of air, it floats to the surface, turning the flooded bog into a sheet of red that growers corral with booms.

Why this time of year

Harvest, almost all of it wet, runs from mid-September to early November, with most of it in October, across the bog country of southeastern Massachusetts. It is a drive from Sudbury, not a walk, and the growers' association has offered public harvest tours out of Carver on October Saturdays; check its site for this year's dates.

How to notice it

  1. Drive southeast toward the Carver, Wareham and Middleboro bog region during October.
  2. Look for a bog flooded solid red, and for a water reel churning the water and booms corralling the floating berries into one corner.
  3. For a guided close-up, check the Cape Cod Cranberry Growers' Association site for public harvest tour dates out of Carver.

Try this with kids: The cranberries float on top of the flooded water instead of sinking. What do you think is inside each berry that makes that happen?

water reel: a paddle wheel driven through the flooded bog to shake ripe berries loose from the vines

Safety

  • Bogs are private working farmland with heavy equipment; watch from public roads or a scheduled tour rather than walking onto a bog.

Sources

  • cranberries.orgCape Cod Cranberry Growers' Association: wet harvest by flooding, water-reel agitation, air pockets make berries float, booms gather them; harvest mid-September through early November; southeastern Massachusetts is the birthplace of the commercial industry.
  • cranberries.orgCCCGA: harvest mid-September to early November, with the majority in October.
  • cranberries.orgCCCGA: public harvest tours on October Saturdays from Carver bring visitors up close to wet harvest and do not involve getting into a flooded bog.
  • umass.eduUMass Cranberry Station: timing of harvest is often based on red color development; light is essential for anthocyanin formation.
  • journals.plos.orgPLOS Climate: warm days and cool evenings in the fall trigger anthocyanin production; growers report poorer reddening without cold September-October nights.

Checked against these sources on September 28, 2026.

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