Harvesting Celery in
Salinas, CA
"The Salinas Valley is in Northern California. It is a long
narrow swale between two ranges of mountains and the Salinas River
twists up the center until it falls at last into the Monterey
Bay." - John Steinbeck, East
of Eden, (1952)
"The Carmel River is a lovely little river. It isn't very long
but in its course it has everything a river should have." -John
Steinbeck, Cannery Row, (1945)
Webpage revised November 20,
2004 BACKGROUND
THE KNIFE
THE SHARPENER
For the past two years I have been
consulting with a vegetable grower in Salinas, CA on improving the
sharpening
methods used in the fields. Currently a vegetable cutter will
spend up to
an
hour thinning and sharpening a new knife before using it in the field,
then he will
spend several minutes sharpening it at each break every day.
Sharpeners
used range from stones to files to steels. My client wanted to
reduce this labor for the harvesters and produce a sharper, more
consistent edge. A fringe benefit would be to reduce the cutter's
resistance to using stainless steel knives. Stainless knives are
being encouraged by the Ag. Dept., but the cutters realize they are
more difficult
to sharpen.
BACKGROUND
The Salinas Valley sits between the Gabilan mountain range on the east
and the Sierra de Salinas hills on the west. Up the valley the
Sierra de Salinas peter out and the valley widens over to the the San
Lucia mountain
range. The Salinas River flows northerly through the valley 150
miles to the Monterey Bay. US 101
roughly parallels the river through the valley. Most of the farm
land is in the wide northern section of the valley between San Lucas
and Castroville, while the southern end has many vineyards.
Salinas, a city of 150,000 and seat of Monterey County, is 20 miles
east of Monterey. Seen from the
air the valley
is a mosaic of fields that produce fruits and vegetables from
artichokes
to zucchini. Okay, zucchini is an exaggeration, but overall it is
the
nation's top vegetable and wine grape producing region, and leads the
world in seed technology, growing and harvesting methods, and
processing technology. See http://www.salinaschamber.com/community/agriculture.html
for more information.
While we also worked on head and romaine lettuce, broccoli and
cauliflower, the celery knife was the most challenging.
A celery field being harvested.
First the celery stalk is cut from the root, then the root end is
trimmed.
Then the stalk is cut to length.
Harvesting up to 3000 stalks a day, the cutter makes between 12000 and
20000
cuts. The cutters (below, left) pass the stalks to the packers
(center) where they are
washed, wrapped and boxed (right). The boxes are put on skids and
loaded on trucks. With all the processing done in the field, all
that remains is refrigeration and shipping. The harvesting
machines are 50 ft. wide and cover 12 to 16 rows, and 100 ft. machines
are in development. Each crew has 12 - 16 cutters and an equal
number of packers, plus drivers and handlers.
THE KNIVES
Some crops, like cauliflower and broccoli, are harvested with butcher
knives, and even the lettuce knife is not that much different.
The celery knife, below, is unusual. It evolved just for this
crop, and is not used for any
other. The tip is rotated 90 degrees and angled for cutting the
root. Although these knives have been made from scratch, most are
made by cutting and welding butcher knives as below.
It has two sharp edges, the tip and the side. Here one cutter is
sharpening the edge while another is sharpening a well worn tip.
The top side is ground flat while the bottom side is convex - a sort of
modified chisel grind.
THE SHARPENER
Our challenge was to find a sharpening method that could be used in the
field. Another consultant from the meat
packing industry walked away from this
because the farmers did not have a sharpening room.
As I mentioned, stones, files and steels were being used and, in the
picture above, a
salvaged industrial grinding wheel. Electric power was available
of some of the harvesting equipment, and my client was willing to add
a generator to the others. We experimented with a variety of
sharpeners - slot devices, wet and dry grinders - an finally settled on
a belt sharpener after it was observed that the small motor could be
replaced with a 12V motor and used right at one of the trucks in the
field. The other advantages of a belt sharpener are that belts
are easily changed, and there is both a straight section for flat
bevels and a slack belt section for convex bevels. We bought a small
motor
and modified ours that same day. It turned out to be under
powered and the sharpener we were using is no longer available, but it
got us off to a good start.
Our next design was a Koval Knives' Little Sharpie modified with
a large
12V
motor. It was more powerful and heavier than we
needed. We based the final design on a low cost 1" x 3"
belt grinder. The right size motor and a special drive
pulley gives the
proper belt speed, and a new base allows operation in the
horizontal position. For more details, see http://www.oocities.org/stevebottorff/Salinas/field.htm
Cutters like their knives to be very thin and sharpened to a 15 degree
single bevel (chisel grind). The initial preparation of a new
celery knife, taking off the original double bevel, thinning and
sharpening, took about an hour manually. With this sharpener it
can be done in under 5 minutes. Sharpenings throughout the day
take just seconds. Our project has been a success!
Steve Bottorff
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