Every year one fifth of America 's total harvest is consumed around one day ; Thanksgiving.

Most of that is cranberry sauce.

Only five percent of the nation 's crop is sold as whole fresh cranberries,

but everything else we eat... the dried sweetened cranberries,

the juice, the sauce, it all starts with this peculiar little berry.

And contrary to popular belief, cranberries don't grow underwater.

So, how do they grow?

We're in Southern New Jersey, one of America 's top three cranberry states.

This region is called the Pine Barrens, a natural habitat for cranberries.

Many of the same families have farmed the berries since the mid 1800 s, like the Leigh Brothers,

this seventh generation cranberry farm.

Cranberries grow on low, trailing vines in sunken beds called bogs.

The plants are perennial, meaning they survive year after year.

Here the oldest vines are over 65 years old.

Cranberries love this sort of sandy soil and they take a long time to grow, 16 months.

You can see here that while the berries are ripening, the buds for next year 's crop

are already growing on the vine, so farmers have to carefully nurture two season s' worth of cranberries at one time.

Water is one of the most precious resources for cranberry farmers.

This 2, 000 acre farm uses only 130 acres to grow cranberries.

The rest is a series of reservoirs and watersheds.

The primary source is the, is the Wading River,

which runs naturally along the farm and we 'll borrow the water during the growing season,

and put it back in when we're finished with it.

We 're simply holding the keys for the following generations after us.

So what's all this water for, if the cranberries grow on dry land?

Well, twice a year, the farmers flood the bogs.

First in December for the duration of winter.

This is when the plants go dormant and their blanket of water

insulates the vines from harsh winter frost.

In the spring, the bogs are drained and the cranberry 's pink flowers bloom.

Nowadays, many farms like Leigh Brothers, hire commercial bees to pollinate the fields.

And by mid June, the fruit begins to grow.

The berries start out green, turn white around August,

and finally red in the fall.