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Cooperative Extension Service.
Copyright 2005, Board of Trustees, University
Circular 440 IV
Growing Sweet Potatoes for Profit
R. D. William & N. J. Tielkemeier
Florida Cooperative Extension Service/ Institute of Food and Agricultural Sciences/ University of Florida/ John T. Woeste, Dean
HARVESTING AND MARKETING
Growing top quality sweet potatoes began with
careful planning, PART I: Planning and Liming.
Then you followed the instructions about Field
Preparation and Planting in PART II. PART III told
you about Field Production and Pest Management.
You are now ready to learn about Harvesting and
Marketing your potatoes.
Digging sweet potatoes requires special care be-
cause they bruise and scuff easily. Rough handling
leaves scars on the potato skin. Remember that a
good-looking, beautiful sweet potato will always
sell better than an ugly, scarred potato.
Sweet potatoes can be dug whenever most of
the roots are large enough to sell. Before digging,
the vines should be cut from the roots. Usually, a
rotary or flail-type mower is used. Be careful not
to set the mower too low and cut the potatoes.
Small plots of sweet potatoes can be dug with
a digging fork. Most growers use a "middlebuster"
plow. The "middlebuster" passes under the middle
of the row and uncovers the potatoes. Digging is
easier if the vines and the side of the bed are cut
away with two coulter discs or disc hillers. The
discs should be set about 18 inches apart and face
Large fields of sweet potatoes can be harvested
with a sweet potato digger. Coulter discs are set
at the edges of the bed. A flail-type or rotary
mower is used to remove most of the sweet potato
vines. The digger removes most of the soil and
lifts the potatoes into large wood boxes. These
boxes are moved to the curing, grading and storage
area on a large truck.
Coulter discs or disc hillers should be set about
18 inches apart to cut the vines and edges of the
bed. A "middlebuster" plow lifts the potatoes and
leaves them on the surface. Pick the potatoes up
soon after digging. Handle them with care to re-
duce bruising or damaging the skin.
Always handle sweet potatoes carefully to re-
duce bruising and damaging the skin. Pick the
potatoes up soon after digging to avoid sunburn.
Cracked, diseased, and low-grade sweet potatoes
should be separated or culled before selling or
Handle sweet potatoes carefully. These potatoes Rough handling caused the scuffs and scars on
will sell because they look beautiful, these sweet potatoes. These marks will lower the
price you get for the crop.
No matter how carefully you handle sweet po-
tatoes, the ends will be broken and some potatoes
will be bruised. "Curing" is needed to heal these
damaged areas on the potatoes.
During "curing," cork or scar tissue is formed
under the bruised area or at the broken end. Curing
also "sets" the skin on young sweet potatoes that
you intend to sell as fresh produce. Roots intended
for storage and sale at a later date must be cured.
Sweet potatoes cure best at a temperature of 85 F
and 85 to 90 percent relative humidity for 7 to 10
days. Ventilation is needed to provide fresh air.
A properly cured sweet potato resists most storage
If you plan to store the potatoes, clean the whole
storage area. Then wash the area and rinse with a
strong bleach solution. The bleach sanitizes the
area and kills diseases. You can cure the potatoes
in the storage room if you dig and place them in
the room within two days. Otherwise, you will need
one area for curing and another area for storage.
Sweet potatoes can be stored for several months.
Clean and sanitize the whole storage area with a
strong bleach solution before storing the potatoes.
Diseases and sweet potato weevil can cause all
your sweet potatoes to rot or become infested with
weevil larvae. If this happens, all your work and
expected profits will be lost.
After the potatoes are cured, lower the tempera-
ture in the storage room to 600F. Never let the
temperature fall below 550F. Temperatures below
550F can cause chilling injury or a hard core in
the potato. As the temperature drops, you should
also reduce the relative humidity to about 75 to
80 percent. Avoid lower relative humidities be-
cause wilting or shrinking will occur. Also, higher
relative humidities may cause more disease prob-
lems. Always ventilate to allow some fresh air into
the storage area.
You can help control sweet potato weevils in
storage by following these instructions:
SWEET POTATO WEEVIL CONTROL IN STORAGE
Insecticide Amount to
Name Apply Remarks
Imidan 5% dust 2 to 4 oz. per Wash in
50 Ib. bushel clean water
Methoxychlor Dilute with talc to Wash in
(Marlate) 25% methoxychlor clean water
and apply 1 Ib. per before
20 crates of dry selling.
GRADE AND SORT POTATOES
Sweet potatoes should be sorted or graded by
size and weight. The best size is 2 to 2.5 inches
across at the thickest point. Most of your potatoes
should weigh between 5 and 10 ounces. This size
is considered a U.S. No. 1 potato. They sell for the
highest price. Jumbos weigh more than 20 ounces
and can usually be sold at a local market. Always
remove the cracked, diseased, or ugly potatoes
Grade and pack your potatoes according to what
your buyer needs. Ask him what size, shape, color
and quality he prefers. Also, ask him what price he
will pay for your potatoes. Then you can sell him
the type of potatoes that he is willing to pay the
top price for. Remember, a beautiful product
packed in a clean crate always sells better than a
dirty or poorly graded product.
Sweet potatoes can be sold at home, roadside
markets, community markets, State Farmers mar-
kets, small grocery stores, and sometimes large
chain stores. But always know your customer or
buyer before you plant your potatoes. Then you can
plant the right variety and grow potatoes that will
Keep a record of your sales. Then you can com-
pare the money you get from sales with what you
spent to find out if you are making a profit.
Now you can ask yourself: Is the profit big
enough to pay for your time and effort? If so, you
are a big success and should begin planning for
next year. But be careful to plan and plant only
what you can handle next year. If your profit was
small, ask yourself if you can improve your pro-
duction and yields without a big increase in costs?
Should you consider another crop or job? These
are questions you need to ask yourself. While your
County Agent or Program Assistant may be able
to help you answer some of these questions, only
you,can make the final decision.
1. Florida Extension Circular 440, "Growing
Sweet Potatoes for Profit".
PART I Planning and Liming
PART II Field Preparation and Planting
PART III Field Production and Pest Manage-
Acknowledgements: The authors thank the many
staff and faculty members of the Institute of Food
and Agricultural Sciences (IFAS), including J. M.
Nehiley, L. Carter, P. F. Korsching, M. E. Marvel,
J. A. B. Pierce, L. T. Christenberry, J. R. Yelvington
and W. S. Cheshire, for helping develop and eval-
uate this production guide.
Special contributions were made by:
F. A. Johnson and J. E. Brogdon Ento-
We also acknowledge the support from the IFAS
Center for Rural Development Programs.
The use of trade names in this publication is
solely for the purpose of providing specific
information. It is not a guarantee or warranty
of the products named and does not signify
recommendation of the product to the exclu-
sion of others of suitable composition.
This publication was promulgated at a cost of
$185.17, or 6.1 cents per copy, to inform both small
and large farmers about sweet potato production.
Single copies are free to residents of Florida and may be ob-
tained from the County Extension Office. Bulk rates are
available upon request. Please submit details of the request to
C. M. Hinton, Publication Distribution Center. IFAS Building
664, University of Florida. Galnesville, Florida 32611.
COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS
(Acs of May 8 and June 30 1914)
Cooperative Extension Service, IFAS, Univerity of Florida
and United State Department of Agriculture, Cooperating
K. R. Tafertiller, Director