Pierce ARC Research Report RL 1979-2
THE MODIFIED IFAS SEMI-MECHANICAL
FRESH MARKET TOMATO HARVESTER
Description, Operation and Crop Production
Norman C. Hayslip and W. W. Deen,
F NS 12.1979
.F.A Univ, of Florida
1/ Professor, Vegetable Crops, University of Florida, IFAS, Agricultural Research
Center, Fort Pierce.
2/ Formerly Assoc. Agricultural Engineer, U. of F., IFAS, Agricultural Research and
Education Center, Belle Glade. Presently Sales Engineer, Torque-Quip Corporation,
IFAS SEMI-MECHANICAL FRESH MARKET TOMATO HARVESTER
Description, Operation, and Crop Production Requirements
Norman C. Hayslip and W. W. Deen, Jr.
An intensive research and development program was carried out by an IFAS-wide
research team during the 1960's and early 1970's to develop the varieties, machinery
and cultural methods necessary for machine harvesting fresh market tomatoes. Industry
interest in machine harvesting then subsided due to an adequate labor supply during
the recession, and a shift by many growers from ground-grown crops to plastic mulch
culture and, on sandy soils, to stake culture. While the use of plastic mulch, fumi-
gation and stakes reduced or solved several problems, these practices also increased
labor needs and per acre production costs. The use of plastic mulch and stakes was
not compatible with the once-over machine-harvest operation. Now, with an uncertain
harvesting labor supply and escalating costs for labor and materials, growers are
again searching for ways to solve these problems, including a renewed interest in
Several commercial processing tomato harvesters modified and tested by IFAS
personnel have shown promise for fresh market tomatoes. They are available to growers
at costs of about $110,000 per machine. Additional modifications of these machines
are needed to provide separate handling of ripe fruit, and to further reduce fruit
damage. Some growers cannot afford the high costs of these machines, and others are
reluctant to invest so much without assurance that machine harvesting is a feasible
and economical practice.
A harvester represents only a portion of the machine-harvesting operation.
Exacting cultural practices designed to meet the needs of the machinery tax the best
efforts of growers. Scheduling fruit maturities for even and orderly handling and
marketing will become a major item. Sorting, packaging and marketing all stages of
maturity will require many changes. Several years of intensive learning and problem
solving will be needed following the adoption of machine harvesting before the system
is refined, reliable and well understood. Growers who anticipate harvesting by
machine will need at least one, and preferably two years of trials on a limited basis
before committing their entire acreage. The semi-mechanical harvesting system
described in this report offers growers a chance to move cautiously into machine
harvesting at modest cost while they gain experience and make economic evaluations of
hand harvest versus machine harvest.
The semi-mechanical harvester was developed to satisfy the following assumptions:
(1) A relatively inexpensive, easily operated and simply repaired harvester is needed
to serve during a gradual transition from multiple hand harvest to once-over machine
harvest. (2) The machine must harvest fruit at all stages of maturity, red-ripe to
mature-green, in order to obtain satisfactory yields of mature fruit. (3) Machine
harvested tomatoes must result in no more, and preferably less damage than those now
hand harvested. (4) Machine harvesting should reduce the number of seasonal laborers
needed and overall costs.
The semi-mechanical harvester concept was based upon the observation that
when a detached, fruit-laden tomato plant was grasped at the base, lifted, and
given an upward jerk all except very small fruits snapped loose and fell to the
ground. With this knowledge and a donated tomato field washer-grader a semi-
mechanical tomato harvester was constructed, tested and modified over a period
of 3 years. A description of the harvester, its operation and crop production
methods necessary for its successful use follow.
Description of Harvester
Detachment of plants from roots. A tractor-mounted 1-inch-square, rotating
bar powered by a hydraulic motor proved best for detaching plants from roots
prior to harvest (Figure 1). The bar is positioned perpendicular to the row and
extends beyond the bed width into the water furrows. Mounted on a hydraulic
controlled tobl bar beneath the belly or at the rear of the tractor, the square
bar operates just beneath the bed surface. This system can be used on crops
without mulch covered beds, or where strip mulch is used. It will not perform
satisfactorily on plastic mulch covered beds, but can be used on paper mulched
beds. About one hour or more is allowed between cutting of plants and harvesting
to promote wilting, therefore, the square bar should be attached to a separate
A method for cutting plants just above the plastic mulch has recently been
developed and is under test (2). The cutter operates to allow pick-up of fruit-
laden plants by the harvester with minimum disturbance of the plastic. This
component has not been tested for use with the semi-mechanical harvester.
Pick-up-elevator. This unit was mounted at the rear of a high-clearance
hydrostatic drive tractor. The elevator was 4' wide and 11' long, and powered
by a hydraulic motor (Figure 2). Four-inch and six-inch pliable plastic tube-
covered rigid fingers were arranged on a portion of the parallel conduit rods
of the elevator for lifting plants. The longer fingers were placed on the outer
edges of the pick-up-elevator to allow for a slightly contoured bed shape.
Flights were spaced 20 inches apart to prevent movement of loose fruit. The
top 30 inches of the elevator angled down about 45 degrees, making it about
parallel to the ground surface. The height of the pick-up end of the elevator
was controlled by the tractor operator. Speed of the elevator was adjusted to
conform to the forward speed of the tractor. Fruit-laden plants were lifted by
the fingers onto the elevator and carried up the 450 incline to about 8 feet from
the bed surface, and discharged onto the plant delivery belt. Spray nozzles
were mounted above the upper portion of the elevator to dampen plants with water
when needed to reduce dust during fruit-vine separation. If the semi-mechanical
harvester is used on plastic mulch covered beds a positive height control
mechanism will probably be required to lift plants without allowing the lift
fingers to touch the plastic.
Tractor-drawn fruit-vine separation, grading and sorting, and fruit transfer
components. These components were built around a used tomato field washer which
served as the basic unit for the semi-mechanical harvester. It was supported by
two 46 x 16, 28-ply rating used airplane tires, and two 7.50 x 16 tires on a
front steering axle giving a 12' wheel base (Figures 3 and 4).
Rotating square bar (B) for under-cutting tomato plants to
allow wilting before harvesting with machine.
Side view of harvester attachment to tractor. Tractor
mounted pick-up, elevator (right) extends above plant
transfer belt (upper left). Tongue attachment and hy-
draulic lines are visible in lower portion of picture.
Front view of semi-mechanical tomato harvester. Pick-up
and elevator (1) mounted on high clearance hydrostatic drive
tractor. Balance of unit pulled by tractor are fruit-vine
separation section over water tank (2) and grading and
sorting section (3) including cross-conveyor (4). Hydraulic
system and controls on tractor operate several motors.
Rear view of harvester. Note seat (1) facing shallow box
and narrow transfer belt for handling red tomatoes. Other
tomatoes are carried via cross conveyor (2) to bulk con-
tainers on truck or trailer traveling along-side.
The fruit-vine separation section (Figure 5) accommodated 4 workers and
consisted of a 44 inch wide, 8 1/2 foot long plant delivery belt, two 300
inclined, upward moving trash removal belts and 4 stages for the workers, all
mounted above the water tank. Tomato plants dropped from the elevator onto the
plant delivery belt which carried the plants to the 4 workers. This belt was
covered with outdoor-indoor carpet to protect fruit from sand and scuff damage.
An inverted "V" shaped metal hood mounted beneath the belt directed falling sand
onto the right and left trash removal belts, thus reducing contamination of
water in the tank.
The steel water tank was about 10 feet long and 4 1/2 feet wide. The tank
bottom tapered from about 22" deep at the front end to 12" deep at the back. A
strainer box 40 inches wide and 18 inches high was mounted on the front of the
tank. Water circulated through a 2" pipe into the forward 1/2 of the box and
through a screen back into the tank. Leaves and trash were trapped in the
forward half of the box and required frequent removal by hand. Sand settled to
the bottom of the tank and moved down the inclined bottom toward a 6 inch dia-
meter capped drain pipe. Sand was flushed out when the water was changed at
noon and at the end of each work day. A pipe inside and across the front of
the tank jetted water through 1/4 inch diameter holes to the rear in order to
force floating tomatoes onto the inclined roller belt.
Chain mounted aluminum rollers 4 feet wide and 2 1/2 inches diameter, with
a 5/8 inch gap between rollers made up the 17-foot-long grading belt which
extended along the bottom of the water tank, then angled upward to grading belt
level. The rollers lifted tomatoes out of the water and moved them along the
8-foot-long grading section (Figure 6). Fan type flood nozzles, mounted above
the belt where the tomatoes were lifted out of the water, washed sand and trash
off both tomatoes and rollers. A 10-inch-wide fabric belt, mounted 4 inches
above and in the center of the grading belt, received red and pink tomatoes
which were separated by hand from mature-green and turning fruits. A 10-inch-
wide fabric baffle hung just above the narrow belt so tomatoes tossed onto the
belt would not be over-thrown. There was an 18-inch-wide grading and sorting
area on each side of the ripe fruit belt. The flow of tomatoes from the tank
was divided by means of a 4 1/2-foot long tapered nose at the front of the
narrow belt extending forward into the water tank. The water pump and grading
and sorting belts were powered by a 7 1/2 HP gasoline engine. The 8-foot long
grading and sorting section accommodated up to 4 workers on each side. -The
workers removed culls and trash, and placed colored fruit onto the narrow belt.
To improve grading, this section should be lengthened about 4 feet to accommodate
2 additional graders, and a small-fruit eliminator. One grader operated the
tractor "stop" and "go" horn signal, another the controls for the cross conveyor
and a third engaged amd disengaged the clutch which powered the grading belt.
A pair of sliding fiberglass doors, each 4 feet wide by 6 feet tall, were
mounted between the fruit-vine separation section and the grading and sorting
sections. This protected graders and machinery from sand and trash which
otherwise would have blown into the grading section during windy weather.
Red and pink tomatoes moved on the belt to the rear where they were caught
in shallow boxes or plastic buckets by a worker seated at the end of the belt
Side view of harvester's fruit-vine separation section,
showing two trash removal belts (center foreground and
background) (1) above water tank. Steps between wheels
lead to two of the four work stages for fruit-vine
separation. Plant delivery belt (2) protrudes below
elevator (upper-right corner).
Chlorinated water bath and flood spray nozzles are used
to buffer fall of fruit and to remove sand and trash from
fruit and grading belt rollers as they emerge from water.
(Original semi-mechanical harvester).
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(Figure 7). As containers of ripe tomatoes were filled they were shuttled to a
trailer for stacking, or placed on the tomato bed to be picked up later by a
loading crew for special handling and packing. Marketable mature-greens and
light pink to breakers were carried by belt to the rear where they fell onto a
padded cross conveyor belt leading to a conveyor which deposited these tomatoes
into a bulk container for delivery to the packinghouse. A decelerator should
be installed on the end of the conveyor to slow the speed of fruit dropping into
the bulk container.
One tractor driver, 4 fruit-vine separators, 8 graders and one box filler
for ripes are required for the semi-mechanical harvester, as constructed at ARC,
Ft. Pierce. The addition of a crew foreman makes 15 workers directly involved
in the operation of the machine. The crew foreman must be thoroughly trained
in the operation, repair and maintenance of the semi-mechanical harvester.
Preharvest cutting of plants to induce wilting is a necessary operation for
satisfactory fruit-vine separation. Wilting reduces limb breakage and fruits
shake free more readily with fewer stems attached. On sunny, warm days the plants
will wilt sufficiently in 30 minutes, but on a cloudy cool day an hour or more
will be required. Since plants do not wilt rapidly during early morning hours,
enough plants for harvesting early the next morning should be under-cut the
preceding afternoon. Plants wilted in the afternoon remain wilted throughout
the night. Therefore, they can be harvested while morning dew is still present.
The pick-up-elevator speed is timed to coincide with the down-row speed of
the tractor to lift plants onto the elevator without pulling or pushing the
plants. The forward speed will average about 1 mph, and will be determined by
the rate at which the 4 fruit-vine separators can perform their operation. The
tractor-operator controls hydraulically both the speed and height of the leading
end of the pic-up-elevator. The lift fingers should project slightly into the
plant bed for best results. If the plants and soil are dry, the spray nozzles
are activated to dampen the plants slightly as they move up the elevator. This
reduces the dust and trash around the workers.
The plant delivery belt should move at the same rate as, or slightly faster
than the speed of the elevator. The trash disposal belts move at about twice the
speed of the plant delivery belt, or about 2 mph. Fruit-vine separation workers
should wear long sleeved cover-alls, gloves, face shields and hospital type gauze
masks in order to protect them from dust and plant applied pesticides. A clean
outfit should be provided daily, and workers should be required to wear all pro-
tective equipment, especially the face mask and shield.
As fruit-laden plants approach, the forward 2 workers alternately remove
every second plant. The remaining plants travel to the other 2 workers located
near the end of the delivery belt. Coordination of this operation is not diffi-
cult with a few hours experience. The plants are grasped at the base, lifted
over the trash disposal belt and given an upward jerk for fruit removal. The
Rear view close-up of semi-harvester. Note narrow belt (1)
for transferring ripe tomatoes into shallow box (below belt).
Other tomatoes fall onto padded belt and are carried into
bulk containers via cross-conveyor (2).
Figure 8. Original
harvester above provided for two workers to
fruit-vine separation. New design provides
and has nearly twice the harvesting capacity.
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plants are then dropped on the belt which guides them into the water furrows.
The 4 workers can handle a total of about 48 plants per minute. With plants
spaced 24 inches apart the tractor would travel a little above 1 mile per hour
to deliver the plants at the rate described. The physical exertion is not
excessive, and is much less strenuous than lugging tomatoes.
This phase of the semi-mechanical harvesting concept deserves further
comment because some question the ability of most workers to withstand extended
periods of this method of fruit-vine separation. The senior author (age 60+)
has personally spent many hours on a work stage doing the fruit-vine separation
in order to evaluate the concept. From the standpoint of fatigue or strain, the
job is not excessive. There are many agricultural labor jobs much more strenu-
ous. However, the work is dirty, and creates discomfort if protective clothing,
face masks and shields are. not' used. The amount of dust and dirt settling on
workers has been decreased by (1) spraying dry plants to reduce dust and (2)
moving the plant elevator further away from workers. If growers recognize the
dirt problem and provide their workers with proper protective equipment the job
should be safe and reasonably comfortable. In a test to determine its accepti-
bility to experienced agricultural workers a grower supplied men who lugged
tomatoes in his hand picking operation. These workers were used on fruit-vine
separation over a 5-acre test plot. They were then asked separately if they
liked the job, and how it compared with their present work lugging tomatoes.
They reported perference for the fruit-vine separation jobs on the semi-mechani-
cal harvester and were not concerned with the dirt.
Tomatoes roll down the trash disposal belts into the tank of chlorinated
water and are then carried out of the water under flood-type spray nozzles and
into the grading and sorting section. Four workers on each side of this grading
belt remove culls, trash and stems, and sort red and pink tomatoes onto the
narrow belt for special handling. The number of graders was limited to 8 be-
cause the grading section of the machine was only 8' long.
Marketable mature-green and turning to breaker fruits are moved via belts
to the rear and onto the cross-conveyor and loading conveyor automatically.
However, 1 of the grader-sorters must operate the height of the loading conveyor
on our harvester since no automatic sensor was installed for this purpose. A
decelerator and sensor is suggested for use on the semi-mechanical harvester's
loading conveyor. Unless the fall of tomatoes from the end of the loading
conveyor is carefully regulated bruising damage will result.
The red and pink tomatoes are carried back to a seated worker who serves
as box or basket filler. His job is to cushion the fall of ripe tomatoes with
his hands as the shallow boxes or plastic buckets are filled, and to move the
full containers to the side while bringing an empty container in place. Another
worker walks behind the machine to remove filled containers and shuttle then to
a worker on the trailer who stacks them. Empty boxes on the trailer are shuttled
forward for placement on the empty box rack to the left of the crew member
Training of personnel is an important aspect of machine harvest. Every
employee should receive special instructions on his specific duties, including
the importance of careful handling for maintenance of fruit quality. The crew
foreman should constantly monitor the workers and machinery, immediately making
any changes or repairs which threaten safety to employees or damage to fruit.
Crop Production Requirements
Precision farming to accommodate once-over machine harvest is essential for
successful operation. Failure to adopt proper practices will result in a highly
inefficient and expensive harvest or a total failure. Some of the more
critical items are discussed.
Only varieties recommended for machine harvest should be used. Florida has
no fully acceptable varieties available to growers at this date. However, the
IFAS breeding program has resulted in several breeding lines that may prove well
adapted and, if so, should become available to growers soon. The variety,
Florida MH-1 is jointless and has the red-ripe firmness necessary. However, plant
size tends to be too large and concentration of fruit set is only fair. It also
may be more susceptible to early blight. Some fruits are slightly pointed and
its mature-greens are not as attractive as those of Walter. In spite of its
weaknesses, Florida MH-1 is suggested on a small acreage for testing machine
harvest operations. Flora-Dade is also a jointless tomato variety which has
found some acceptance by growers and produce buyers. While fruit shape and
appearance of Flora-Dade mature-greens are better than Florida MH-l's, it pro-
duces a larger and more vigorous plant, and its red-ripe fruit are not as firm as
MH-1 red-ripes. Flora-Dade is also suggested for trial. Extreme care in hand-
ling red-ripes must be used to prevent bruising.
Uniform, concentrated maturity within a crop is a primary requirement for
machine harvesting requiring the best efforts of growers. Level land and a
uniform soil type with excellent water control capability will contribute to the
concentration of maturity. Plug-mix seeding or high quality containerized trans-
plants are suggested. Soil treatments for insect and disease control will insure
a good stand.
Flat bed tops and smooth water furrows should be precision made and main-
tained throughout the crop. Weed control must be excellent. Rows should be at
least 600 feet, and preferably 1200 feet long with ample smooth turn spaces at
Single row plant spacing should be a uniform 24 inches for 1 plant or 30
inches for 2 plants per hill. Exact plant spacing is important because plants
are lifted 1 at a time for fruit-vine separation. Irregular or closely spaced
plants will tangle and will be difficult to separate for shaking. If double row
beds are used the plants should be opposite (not staggered). However, double
rows of existing varieties are not recommended because the combined total width
of plants will be excessive, and plants will tend to run off the bed shoulders
into water furrows. The width of the plant cannot exceed 52 inches because the
pick-up elevator is only 48 inches wide. Plants wider than 52 inches (26 inches
to each side of the bed center) will be caught at the corners of the elevator.
Heavy nitrogen applications often will produce rank vines which must be hedged
back to 48 inches wide before harvest. Until a more compact tomato variety is
developed it is best to limit the amount of nitrogen used (about 140 pounds of N
per acre on sandy soils is suggested).
Converting from hand harvest to machine harvest will require variety, cul-
tural and fruit handling changes. A logical first step for growers is to plant
and machine harvest a small portion of their crops for two or more seasons. The
harvester described, because of its relatively low initial cost and simplicity
in operation, maintenance and repair, is suggested for use during this transition
period. By providing for 2 additional workers for fruit-vine separation the
capacity of this harvester is now about twice that of the earlier model (Figure
8) described in 1974 (1).
Keeping fruit damage to a minimum was a major criterion in the development
of this harvester. In most instances, once the source of damage was pin-pointed,
it was possible to make changes to eliminate it. In light of these results the
minimum standard for any fresh market tomato harvester should be that fruit
damage not exceed that obtained from commercial hand harvesting.
Any modern machine shop's personnel should be able to build and improve on
the harvester described here, with the help of one knowledgeable in tomato
culture and fruit handling.
1. Hayslip, Norman C. and W. W. Deen, Jr. 1974. The IFAS Semi-mechanical fresh
market tomato harvester. Proc. Fla. State Hort. Soc. 87:139-143.
2. Shaw, L. N., H. H. Bryan and George Cooper, Jr. 1978. New developments in
mechanical harvesting of fresh market tomatoes. Proc. Fla. State Hort.
Soc. 91: In Press.
The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
site maintained by the Florida
Cooperative Extension Service.
Copyright 2005, Board of Trustees, University