Original subtitles

- [Narrator] Harevesting provides humans

with over 2 billion tons of fruit and vegetables every year.

It's one of the most crucial industries on the planet.

- [Dennis] It's dangerous work up there,

one slip and they could end up in a world of hurt.

- [Narrator] These high tech wonders have transformed

America's 2 million farms into a $140 billion industry.

- [Mitch] You're talking about the ability to harvest

4,000 or so bushels an hour.

- [Narrator] From optical fruit sizers

to computer controlled corn picking combines.

You'll never shop for produce the same way again,

on "Modern Marvels."

[electronic music]

[upbeat music]

- [Narator] Every year, from spring until fall,

California's fruit harvest is in high gear.

At Reimer Farms in California's San Joaquin valley

they're picking nectarines.

For all growers, stretching the harvest season

means raising different varieties of the same fruit.

- We have varieties planted specifically

throughout the different times of the season

to fulfill those different time slots

for providing fruit to the marketplace.

So a typical variety of nectarines

may harvest for two to three weeks.

- [Narrator] A good harvest depends on fruit

that looks and tastes its best.

To add maximum appeal to a nectarine,

most growers line the orchard rows with strips of Mylar.

The reflective surface concentrates the sun's rays

into the tree canopy, promoting photosynthesis

and increasing the sugar content

and color quality of the fruit.

- And then that's when the fruit's

actually going through its sizing process.

It's when it's developing its sugar,

developing its color.

And so we're trying to maximize its environment

during that particular critical time point before harvest.

- [Narrator] As the workers begin picking,

growers will spot check the fruit

to verify their decision to start harvesting.

- So what we'll do when we're trying to decide

whether we're harvesting properly is

we'll sample them with a penetrometer

to see what the flesh firmness is

to determine whether we are picking the level we want.

So we just quickly just shave a piece of the skin off.

And then we use this plunger to push in there.

And the force that it takes to push that in

will then determine the flesh firmness.

This one rated at 11.

- [Narrator] Picking is no longer the last step

in the harvest.

In many cases, it's just the beginning.

This 10 acre packing facility

operates three state of the art packing lines

for boxing peaches, plums, blueberries,

apples, and many other fruits.

Today, it's nectarines and pomegranates.

In one shift, the workers can back up to 120,000 boxes

of fruit on two lines.

All of it sorted, according to size, color,

and degree of ripeness.

- We become almost the warehouse for the grocery store.

So they'll give us an order and give us

only like a one or two day lead time to pack it,

put it on a truck and get it over to anywhere

in the United States.

- [Narrator] Once a piece of fruit is picked,

its limited lifespan

sparks the race to preserve freshness.

Here, sophisticated post-harvest handling

is a way to stall for time, starting with a cold shower.

The hydro-cooler pours frigid 32 degree water

over the fruit to reduce its internal temperature

and slow down decay.

- This is absolutely crucial in maintaining good quality.

In the harvest season in California in the summertime,

our temperatures can be well over 90 degrees Fahrenheit,

even a hundred degrees Fahrenheit.

And the fruit will lose quality quite quickly.

It will dry and lose sugars.

- [Narrator] The cooled fruit quickly makes its way

onto the sorting line for a quick wash and wax.

After it's rinsed,

it's sprayed with a vegetable oil product

to help prevent moisture loss

during the long journey to the supermarket.

Before sizing begins,

inspectors use their highly trained senses

to remove the subpar fruit.

- As they touch it, they're looking for a soft shoulder

or soft tip on the fruit

that would bruise or damage easily

and could later decay in transit.

So that piece of fruit that's a little bit too soft

is then removed.

- [Narrator] The rejects are diverted

and will later produce juices, jams,

and other processed products.

The fruit that passes inspection

continues its journey to the high speed sorting line.

For centuries, farmers have sorted fruit

to achieve uniform shipping weights

and to satisfy consumer preference.

The first packing houses used crude sizers,

with wooden slats or holes

through which the smaller sized fruits would drop.

Today, the optical fruit sizer is a faster,

more accurate method.

The fruit is first diverted onto a single file cup conveyor,

moving at about 10 pieces per second.

As it passes into the sorter,

each piece is rotated and photographed by two lenses.

An infrared lens gathers shape and dimensional data

and a color lens collects the color qualities of the fruit.

The camera quickly snaps 25 photos

to create a two dimensional projection of the entire fruit.

From this picture, the computer interprets its exact size,

shape, and color.

- Now we've got a full look at it

and then we can determine if the amount of color

that we see, red versus yellow,

is the appropriate color that's desirable for packing.

And that's helpful in markets where we want to send fruit

of a uniform size, color and shape.

- [Narrator] Once the computer obtains the mugshots

of a certain piece of fruit,

a timing device triggers a lifting finger

that deposits the fruit into a specific lane

according to size and color.

This high tech sorter delivers nearly identical fruit

to each of many packing lines.

After a final human inspection,

the fruit is hand packed in a variety of boxes.

- [Kelvin] Then it's conveyed by forklift

into a cold storage room where it's stored

at an ideal or optimum temperature

that actually puts the fruit to sleep.

Once the fruit is in that condition or in that state,

it's in the best environment to be transported

from California to the various markets in the Midwest

or the east coast.

- [Narrator] The packing house can even hold boxed fruit

at a higher temperature to force ripening.

Sophisticated post-harvest handling of fruit

is a progression and a ritual

that has remained otherwise unchanged

over thousands of years.

This Egyptian tomb drawing dated at 1900 BCE

depicts two workers harvesting a fig tree.

- The key components of harvest are the same.

One's picking the fruit and then putting it into a basket.

The other is sorting the fruit

and putting it into a consumer package.

The practices involved in picking and packing

are basically still the same and haven't changed.

[gentle music]

- [Narrator] Ancient Egypt is one of the birthplaces

of horticulture.

The first growers learned to irrigate their fields

by tapping the Nile River's seasonal floods.

But without modern technologies,

these growers were faced with the problem of spoilage.

- They didn't have refrigeration,

and they didn't have canning.

They didn't have these other processes

to preserve the harvested crop.

So the crop had to either be consumed fresh

soon after harvest or dried and stored dry.

- [Narrator] China was the birthplace of temperate fruits,

such as peaches and pears more than 4,000 years ago.

The Greeks and Romans oversaw thriving fruit trade

throughout the Mediterranean.

When Mt. Vesuvius erupted in 79 CE,

the Romans were cultivating extensive orchards

including peaches, citrus trees, and grapes

on the volcano's slopes.

During the middle ages,

monks were the most sophisticated growers.

They practiced the skills of tree grafting

and cross breeding to produce new varieties of fruit trees.

The colonists brought Europe's fruit tree saplings

to the new world,

but the true American orchard revolution

was again fueled by monks.

As the Spanish moved north into California

and established missions in the 1600s,

the monks took advantage of the dry climate

and raised large orchards of grapes, figs,

peaches, pears, and apricots.

As settlers moved to California in the 1800s,

the orchards fanned out to supply the new urban centers

of Los Angeles and San Francisco.

Growers also planted in the Sierra Foothills

to feed the influx of gold miners.

California fruit production exploded in the 1890s

when refrigerated railroad cars

allowed growers to ship fresh fruit

to the huge east coast markets.

But in the coming decades,

the small family operated farm would nearly vanish.

- Farms began to get bigger

primarily because of competition.

There's a continuing pressure to reduce the price of fruits

and vegetables at retail market.

And that means the farms generally have to get larger

in size to take advantage of economies of scale.

- [Narrator] Large vertically integrated growing

and packing operations are now the standard

in US fruit production.

But labor remains the most unpredictable

and expensive cost for growers,

especially when balancing a need to pay a decent wage

while providing affordable produce for consumers.

Beginning in the 1960s,

engineers from the University of California at Davis

began testing a multitude of mechanical fruit harvesters.

Various tree shakers and shake-and-catch machines

were very effective at harvesting fruit quickly.

But the percentage of damaged fruit was unacceptable.

Half a century later,

there are still no commercially viable mechanical harvesters

for picking many types of fresh fruit.

One solution may be a man machine interface

that allows laborers to more efficiently access

the tree canopy.

Here, a pear grower and engineers from UC Davis

are testing a modified European built platform

in Northern California.

The machine offers six moveable picking platforms

at three different heights

allowing the harvesters to move laterally

or up and down inside the tree canopy.

- So the workers, instead of placing fruit into bags

and delivering it to bins,

would place fruit two or three at a time

into little feeder conveyors

that fed into a main elevator.

At the top of the main elevator,

the fruit would go into what's called a bin filler

where the fruit is lowered and placed into a rotating bin,

which ensures even distribution of the fruit in the bin.

- [Narrator] By eliminating the need to carry heavy ladders

and picking bags, the platform might expand

the potential workforce.

It could also improve employee safety

by reducing hazardous working conditions

and injuries from ladder falls,

a major problem for many growers.

The harvesting platform has already gained a firm footing

in Europe where hand labor has been in short supply

for decades.

- [Narrator] In the Midwest, America's biggest harvest

has eliminated handpicking

and put the farmer at the wheel

of a computer controlled maximum efficiency machine.

Nebraskan John Sandahl is harvesting corn

in a John Deere 12 row combine.

The air conditioned cab may seem cushy

and combining corn may look a bit like mowing the lawn

but this harvest demands a sharp eye

and fast decision making.

- While harvesting corn, I'm scanning the corn head

all the time, watching for objects in the field,

make sure that all the row units are functioning properly.

Pulling the corn stocks down through.

And this corner post monitors all the functions

of the machine.

The first one down here has the engine RPM,

the speed that I'm traveling,

the middle one is the grain loss monitor.

That's very important.

It keeps track, monitors how much grain

the combine is losing off the bat.

- [Narrator] A small percentage of the harvested corn

drops back in the field

and the operator minimizes these losses

by slowing down when necessary.

The modern combine is a factory on wheels.

As corn stalks enter the corn head,

a series of rollers pulled down on the stalks

and snap off the ears.

An auger moves the ears into the combine

where they're conveyed into the threshing mechanism.

Here, a spinning rotor threshes the kernels,

removing them from the cob

while a strong fan blows out the leaves and chattel.

The kernels are then conveyed to the

combine's holding tank.

On Sandahl's farm, the corn is offloaded onto trailers.

The kernels are loaded into bins

that will store the grain and complete the drying process.

Corn is a crop with many uses,

everything from tortillas to corn syrup, animal feed,

and ethanol, a corn based alternative fuel

that is boosting demand across the corn valley.

More than 7,000 years ago,

it was a decidedly simpler crop.

In the region that is now Mexico,

natives began harvesting a wild grass called teosinte.

Over thousands of years,

the meso Americans domesticated teosinte

by sewing and reaping only the best kernels.

It evolved into a hardier,

more productive plant known as maize or corn.

After its first migration north at about 1200 BCE,

it would become the most important crop

in American agriculture.

- When the pilgrims first arrived,

they planted in small hills,

several seeds in a hill.

They grew the corn,

they harvested the ears and they ground it into flour.

[gentle guitar music]

- [Narrator] In the colonies,

and for centuries that followed,

corn was harvested by hand.

The corn knife with an 18 inch blade

was one of the original methods of the stalks.

When farmers were picking only the ears,

handheld hooks or pegs made of iron and bone

were the standard tools.

- This is a bone peg, probably used in 1890.

They used anything that was sharp

to open up the shuck at that time.

- [Narrator] Gloves with embedded hooks

later replaced the peg.

- People in rural communities are very innovative.

And so they were always looking for some way

to do it better, to do it faster.

The hooks and pegs allowed for faster harvesting

because they could rip the shuck away from the ear,

snap it and harvest it much quicker than just by hand.

- [Narrator] Even today, many rural communities

still celebrate the days of hand harvesting

with husking bee competitions.

Ted Martin is a former Nebraska state champion.

- You grab the ear towards the end like this

and come in with the hook crossways, open up the shucks.

Then you peel 'em back and you snap the ear out

and throw it.

And it's all one motion, really.

- [Narrator] A fast Husker could generally harvest

about a 100 bushels or one acre of corn per day.

But enormous advancements in agricultural technology

allows modern farmers to dwarf this number.

- [Narrator] Now we return to the fields

here on Modern Marvels, Harvesting Plus.

Tillers, combines, cultivators are just some

of the innovative pieces of farming gear

that have revolutionized harvesting in the modern era.

But long before machines like tractors

and harvesters took over,

farming meant putting your shoulder to the wheel.

For decades, nearly every farm was equipped

with a hand operated corn sheller.

- Okay, we've got a couple cobs of corn

and we're looking at a hand powered corn sheller.

That's about a hundred years old

and we're gonna run a couple cobs through it.

First, I'm gonna crank it up.

Couple plates inside the machine

going in opposite directions

are gonna shear the kernels off.

The corn kernels go down the bottom,

the corn cobs come out the other end.

And there's a fan at the bottom

that blows some of the chaff away as well.

- [Narrator] Many farmers harvested corn

for silage or animal feed.

This included the stalk as well as the ear.

Silage was the first corn harvest to see mechanization

in the form of the corn binder in the late 1800s.

On one Nebraska farm,

Ron Lange operates an antique corn binder

to harvest feed for his horses.

- It's an international corn binder.

Just press it and ties it.

This mainly would used to be used more for green corns

and fill silos with it.

They would cut the corn green

and haul it in and fill your silos.

- [Narrator] The binder both cuts

and then automatically ties the stalks into bundles

with twine.

The operator uses a foot clutch

to engage a conveyor that drops the bundles in the field.

Corn binders were usually followed by a crew of laborers

who stood the bundles into larger upright stacks,

known as shocks.

According to Ron,

this traditional shock building technique

prevents mold from growing in the bundles,

which helps keep the feed from rotting.

- Shocking is for your winter feed

and it would mold and stuff on the ground.

And the shocking is for curing, you gotta shock it

so the wind goes through it.

- [Narrator] Up through the Great Depression,

the meticulous hand harvest was still the only way

to pick the ears directly.

The first mechanized corn pickers,

powered by internal combustion engines,

debuted in the late 1930s

and would soon double productivity

to 15 acres in one day.

The pickers selectively harvest only the corn ears,

depositing the stalks back in the field.

Farmer Randy Jensen uses a two row 1960s model,

237 John Deere Picker to harvest

600 acres of corn each year.

The picker uses rollers to snap the ears off the stalks.

The ears travel to a husking vat

where rubber rollers remove the husks.

The clean ears then drop in a wagon.

- When you come to the end,

you'll have a full wagon most of the time,

and you'll have a guy at the other end

and he'll switch wagons with you.

And he'll take it home and run it to an elevator

which elevates it up into an ear corn crib.

And basically, that's all you do.

- [Narrator] While the mechanical picker

has endured for decades,

they couldn't shell, clean, and dry corn

immediately in the field.

By the mid 1950s, there was an answer.

The combine, which had long before mechanized

the harvesting of other grain crops

was now advanced enough to produce clean corn kernels

at a staggering pace.

What began with two row designs

grew to the 12 and even 16 row corn head combines

of the 21st century.

- You're talking about the ability to harvest 4,000

or so bushels an hour, which translates to, you know,

maybe 60 to 70 pounds of grain, clean grain

every second that this machine can harvest.

- We go back to working with a corn binder.

We're talking about working maybe eight acres a day.

And now we're talking about hand picking,

we're talking an acre or so day, 100 bushels.

Today's big farmers with large combines

can do 40,000 bushels in a day with one combine.

- [Narrator] The American corn harvest relies on the size,

speed, and sophistication of one machine.

- [Narrator] Every year in October, there is a fruit

that must first go for a swim before it can be picked.

[upbeat music]

Just days before harvesting, farmers in central Wisconsin

divert water from nearby reservoirs

in order to flood thousands of acres of cranberries

in up to two feet of water.

This is called a wet harvest.

The berries grow on short vines.

When they mature,

the fields are flooded to make harvesting easier.

These water reel harvesters, also called beaters,

will transform the marsh into a sea of red.

- And the first guy that goes in the water

is opening the bed

and then the rest of the guys behind him

just keep following along behind him.

What they're looking for in the water

is what we call a berry line,

where you can see where the fruit's been picked clean

and where the remaining fruit is.

So you try to line up on that.

And the idea is to not miss any fruit

and beat it clean or pick it clean.

- [Narrator] As the beaters move through the vine,

they strip off the berries.

Cranberries contain four air chambers.

When freed from the vines,

their natural buoyancy causes them to float.

- Cranberries are trained,

meaning the vines lay a certain direction.

Good analogy would be like petting a cat the right way

and the wrong way.

You pet it the right way, everything's nice.

You go against the vines or against that cat

and his fur gets all ruffled up

and it's not a very nice thing.

Same thing can happen with cranberries.

If we go against the vines,

we'd rip them outta the ground and it would be a mess.

- [Narrator] Once the three acre bed is beaten,

the workers deploy a cran boom to slowly coax

the flotilla to one end of the marsh.

Here, more than 80,000 pounds of berries

are loaded by elevator and trucked out.

At the Ocean Spray receiving station,

the berries are offloaded into holding tanks.

[upbeat guitar music]

And then conveyed into the packing houses

where they're cleaned and then sized.

These cranberries are destined for processing,

meaning they will end up as juice, sauce,

or even Craisins, the cranberry equivalent of raisins.

But long before cranberry juice and Craisins

dominated the market,

Native Americans understood the power of the fresh berries

using them in medicines, poultices, and dyes.

Dried berries were even pressed together with venison

and fat to produce pemmican, a survival cake

that kept for long periods of time.

The first commercial growers in the 19th century

recruited cheap field laborers, often women and children,

to meticulously hand harvest the wild growing vines.

- When the men, women, and children would show up

on the cranberry marsh, they were given a measure.

Once they had a full measure,

they would go over to the edge of the bed,

dump the measure into the receptacle.

And that picker was given a picking chip.

That picking chip would be used for either cash

or merchandise at the company store.

- [Narrator] In the 1890s, the first cranberry hand rake

replaced the picker's calloused fingers

and quickly became the harvesting method of choice.

Growers eventually discovered that flooding

the cranberry beds made hand ranking much easier.

- This is the hand rake, it's got metal teeth

with slots in it.

As you rake, you go through the vines like that.

The berries are floating on top of the water.

They're attached to the vines,

but you still gotta take 'em off.

And it's a back wrecking job

if you have to do it all day long,

especially if the vines aren't trained.

- [Narrator] In the 1950s, Wisconsinite Leonard Getsinger

designed one of the first

successful mechanical harvesters.

The hand pushed Getsinger picker

uses retractable metal teeth to comb through the vines

and pick berries.

Up until the 1970s,

the majority of all cranberries were sold as fresh fruit

for traditional cooking.

- During the 1970s and 1980s, the juice market exploded

and the demand for cranberry juice far exceeded the demand

for fresh cranberries.

The whole industry shifted from fresh fruit

to processed fruit.

- [Narrator] Starting in the 70s and 80s,

most farmers began wet harvesting with beaters

to bring in a larger, yet less carefully handled crop.

But today, one man feels there is still a better mouse trap

for farmers who raise cranberries for processing.

It's called, The Ruby Slipper.

- It's a machine I invented trying to find a simpler,

faster method to harvest cranberries

that was easier on the fruit, easier on the vines.

This is a lot gentler.

The bar itself is traveling at a slower speed

when it contacts the vine,

but the ground speed of the machine is a lot faster.

- [Narrator] The Ruby Slipper is pulled through the marsh

and requires no moving parts to remove the cranberries.

Regardless of the machine, harvesting cranberries for juice

or Craisins is not a gentle affair.

But there's another harvest more steeped in tradition

that demands a more delicate touch.

Habelman Brothers in Tomah, Wisconsin

is one of the world's largest producers

of fresh cranberries.

This harvester is all about delivering the perfect berry.

Habelman's harvesters utilize stainless steel teeth

to comb the vines, much like the original Getsinger pickers.

But these gentler modern harvesters

use a series of paddles to free the berries from the vines.

- The berries never end up back in the water.

They go right into the boats and then into the trucks.

We can do about 10 acres a day

with the two machines that we're using right now.

- [Narrator] When it's time for packing,

the berries go through a separator line

to remove discolored and poor quality berries.

At the front end is an antique device

that has never been upgraded or redesigned,

the Bailey Separator.

Invented by the H.R. Bailey Company in 1917,

it was conceived with the idea

that only fresh cranberries will bounce.

- So they pass through a series of boards,

good ones jump and land on a finish belt.

The bad ones just kind of filter down the machine.

And a lot of companies have tried to come up

with a better design, but there isn't any out there yet.

- [Narrator] The cranberries that pass Bailey's tests

are then double checked by more modern equipment.

Two different electronic separators use ultraviolet

and fluorescent light to detect inferior color and rot.

After the antique and high tech separators have their go,

the final quality check is human.

Any bad berries that have survived the gauntlet

are weeded out before packaging.

As the demand for healthier food and drink continues to spiral,

a wild assortment of cranberry harvesting machines

will continue to prowl the marshes of central Wisconsin.

[western guitar music]

- [Narrator] In the low desert

of Southern California's Coachella Valley,

there's an annual ritual that is perhaps the most dangerous

harvest in America.

This man is a palmero.

His job is to harvest dates from trees

that can grow to heights of more than 80 feet.

Date grower Dennis Jensen speaks to the industry's anxiety

over the ladder harvest.

- It's dangerous work up there.

One slip, and they could end up in a world of hurt.

As much as we try safety wise,

it seems that every other year,

we lose someone to this terrible tragedy.

Some of the other items that are very dangerous

are the spines,

the palm fronds themselves that can pierce your hand

or an eye, or an arm, or a leg, or foot.

And they're located throughout the crown of that tree.

So there's a lot of different dangers

that they have to work with.

- [Narrator] The palmeros in this field

are hand harvesting a premium date, known as the Medjool,

one of several date varieties that have been cultivated

since before recorded time.

Dates are likely the oldest of all harvested fruits.

Nearly 6,000 years ago,

they were cultivated in the region of Mesopotamia

or what is now modern Iraq.

Some traditions trace the fruit to the garden of Eden.

- Even the Bible refers to the land of milk and honey,

and we've been old by Jewish scholars

that the honey it was referring to

was the honey of the date palms.

- [Narrator] Its ability to grow and produce fruit

in such an arid environment

made the date palm a sacred tree.

- Dates keep very well.

And in that hot desert area where they had no refrigeration,

they could keep them for a long time

and early on they'd discovered the ways

to press them together to get rid of air and so forth

so that they would keep.

- [Narrator] After many failed attempts,

date palm offshoots were successfully imported

and planted in the Arizona desert in the year 1900.

The coveted Medjool offshoots came from Morocco in 1927

and were later planted in the Coachella Valley.

Today, California growers of Medjools

and the other major variety, the Deglet Noor,

oversee a thriving industry that annually harvests a crop

worth around $50 million.

And it's not just the fruit that is valuable.

The date palm is considered so beautiful

that as many as 15,000 trees are harvested

and sold each year to real estate developers.

The times are changing for the skilled palmeros.

Most date growers are relying less on the ladder harvest

and more on a mechanical harvesting aid.

The Canasta.

Mounted on a nine ton lift, the platform opens and closes

around the date palm's trunk.

Even as mechanization makes the work safer and easier,

the job still requires a trained palmero

to distinguish dates that are ripe for picking.

- Normally, what they're gonna do

is they'll be looking for the ripest ones

and they're pretty easy to pull off.

And sometimes you can just shake them

and they'll actually fall off of the bunches,

but they'll be pulling off the ripe ones,

which are the darker color ones.

There's yellow ones on here, which are not ripe yet.

It'll take another,

probably two to three weeks before they will ripen up.

- [Narrator] Prior to harvesting,

the palmeros wrap each and every growing date bunch

in a nylon bag.

- Our date bags are used to keep moisture away

from the dates should we have a sudden thunderstorm.

And the rain,

the moisture causes a lot of decay for the dates.

Additional purposes of these bags are to keep insects away

and to keep birds from eating the dates.

[upbeat rock music]

- [Narrator] To prevent damage to the delicate fruit,

harvesters lower small baskets to the ground

where they're hand sorted for ripeness.

After a short journey to Dennis Jensen's

Seaview packing house, the dates are cooled.

Then they're carefully washed and dried

before they're hand sorted for packing.

One of five quality categories are assigned

before the dates are shipped to points around the world.

- [Narrator] Welcome back to Harvesting Plus.

Today, Kennett Square, Pennsylvania

is known as the mushroom capital of the world

and not long ago,

the world's largest mushroom grower was Creekside Mushrooms

located near Pittsburgh.

Creekside owners have since moved on to other ventures,

but for many years, its 800 acres of limestone tunnels,

burrowed beneath trees and pasture lands

was a fungus farmer's fantasy.

- The neat thing about growing mushrooms

at this particular facility is that the temperature

is pretty much consistent all year round.

And we maintain about a 62 degree temperature

all year round and about a 95% humidity,

which allows mushrooms to just recycle themselves

pretty much every 24 hours.

- [Narrator] Here, the fungus of choice

is the Sylvan White Agaricus,

the ever popular white button mushroom.

A small army of harvesters

speeds from one cave to the next.

Each worker aiming to pick up a minimum

of 55 pounds an hour.

Mushrooms are grown in

and harvested from large wooden trays.

Each tray is harvested in passes or breaks.

The first break yields the large and medium mushrooms.

Removing the larger fungi allows more room

for the smaller mushrooms to grow and develop.

- I'm picking the mushrooms that are ready,

at the prime time for harvest.

And that depends upon the stem length,

the shape of the cap, whether it's domed or oval.

If you notice the only smalls that I take

are the ones that come off basically by accident,

they're left on there for tomorrow.

They'll be mushrooms that will be harvested again tomorrow.

- [Narrator] Each tray ultimately yields

approximately 250 pounds of organic mushrooms,

but not every mushroom is perfect.

- [George] This mushroom in particular

has a blemish on it.

That is what we consider a number two.

It would not look as nice when it hits the supermarket.

- [Narrator] The popular White Agaricus mushroom

was first domesticated in the cellars and sewers

of 19th century France.

The process of producing the spawn

or seed was the key to growing the fungus commercially.

After the French perfected a strain of spawn,

it was soon exported to England

and ultimately to the United States.

The mushroom business took off in 1904

when the United States Department of Agriculture

perfected a domestically bred spawn.

One of the very same strains that are used today.

Even with the healthy spawn,

profitability growing mushrooms in vast numbers

is a very demanding craft.

The process begins with piles of hay, straw, and manure.

This compost is turned, adding water and fresh air

to speed up decomposition.

The compost is then pasteurized

in a fresh air tunnel system.

- It kills all the other microorganisms

that are in the compost so that when we do plant the spawn

or the mushroom seeds into the tray, it gives a nice,

clean medium for the spawn to take hold inside the compost.

- [Narrator] Each tray is filled with compost

and the spawn is then added.

The trays are transported deep within the pitch dark

limestone caves to begin coaxing the root structure,

or mycelia, to the surface.

This tray of organic White Agaricus

will begin harvesting around day 15.

Its many mushrooms then travel to a packing facility

where they're weighed, packaged,

or sometimes sliced, before they're cooled

and quickly shipped to market.

- We don't get a whole lot of lead time

nor do we want a whole lot of lead time

because what we produce today,

we wanna make sure we ship within the next 24 hours.

- [Narrator] While the mushroom harvest may seem stable,

its future is not.

- People that get outta high school today,

look for other opportunities.

So it gets harder and harder to find labor.

- [Narrator] Today, mushroom growers have only 75%

of the workforce needed to harvest at full capacity.

Mushrooms are not the only crop impacted by a lack of labor.

The trend is affecting harvests across the nation.

- There's certainly less labor available.

It began several years ago,

but the increased pressure to reduce illegal immigration

across the Southern United States border

has influenced the amount of laborers

that are available for harvest.

- [Narrator] As workers become scarcer,

mechanization will play a larger,

but probably still restricted role, in the harvest.

- Labor is the most important factor in this business.

When you look at the fragility or the nature of the fruit,

this is not something that is conducive

to mechanical harvesting.

We rely very heavily on a labor force

that's skilled to discern fruit quality on the tree.

And there's really no other way to go about doing that.

- [Narrator] Truly our machines will become

more sophisticated and sensitive

and a declining labor force

will spur that mechanical innovation.

But only time will tell if the machine

will ever match the human hand's ability

to delicately pluck an unblemished piece of fruit.