fi UNIVERSITY OF Cooperative Extension Service
SFLORIDA Institute of Food and Agricultural Sciences
SWcA Vegetable Crops Extension Publication
Horticultural Scice Department D.O. 110690 Gainesvll-e, n 32611 Telephone 904/392-2134
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November 18, 1994
I. NOTES OF INTEREST
A. Vegetable Crops Calendar.
H. COMMERCIAL VEGETABLES
A. Plastics Disposal The Larger "Disposal" Picture.
B. Reminder on Effective Sanitization of Packing Lines.
S \l III. VEGETABLE GARDENING
A. Florida's Biggest Vegetables 1994 Update.
Note: Anyone is free to use the information in this newsletter.
Whenever possible, please give credit to the authors. The purpose of
trade names in this publication is solely for the purpose of providing
information and does not necessarily constitute a recommendation of
The Institute of Food and Agricultural Sciences is an Equal Employment Opportunity Affirmative Action Employer authorized to provide research, educational
information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap or national origin.
I. NOTES OF INTEREST
A. Vegetable Crops Calendar.
December 6, 1994. Gadsden Tomato
Forum, Sawano Club, Quincy, FL, 9am-lpm.
Contact Ben Castro, Gadsden Co. Extension
March 2, 3, 1995. 1995 Florida
Postharvest Horticulture Institute. Holiday
Inn West, Gainesville. (contact S.A. Sargent,
904-392-2134 ext. 215).
March 6-9, 1995. Harvest and
Postharvest Handling of Horticultural Crops.
Industry Tour. (contact S.A. Sargent, 904-
392-2134 ext. 215).
II. COMMERCIAL VEGETABLES
A. Plastics Disposal The Larger
We should remind ourselves every
once in a while that the solutions to the
"disposal" of agricultural plastics, indeed all
plastics, is not just "get rid of them". It is
perhaps better to say, "let's shepherd our
resources as effectively as we can" in the use
of agricultural plastics.
One of the more recent technological
areas is that of degradable plastic mulches. In
experimental use since the mid 1970's, these
started as photodegradable, then came
biodegradable and under that heading are
those which create small particles of
polyethylene and another group which are not
polyethylene at all and are truly degradable.
The polylactic acid polymers are in that
category and, though not plastics, the new
paper-based mulches are also. Each kind has
had its proponents, its application difficulties
(including price) and its failures, yet attempts
to make this approach work continue to gain
momentum. We have it on good authority that
the photodegradables continue to increase
their market share and geographic penetration.
They are not just popular in the south or west.
Many mid and northern states now have
growers using domestically produced
Under the notion of "disposal" there
are at least three general approaches, true
recycling into either identical or other suitable
products, conversion to energy as fuel
(hopefully, recovered energy), and chemical
recovery. Another section of this Review talks
in more detail about chemical recovery. One
should not consider putting plastics in a landfill
as "disposal". It is nothing more than long-
Under the notion of "shepherding our
resources" we should also place the idea of
using less plastic. There is always an ongoing
competitive battle for who can make the
product with fewer pounds of polymer. This
is one of the reasons why linear, low-density
polyethylene and high-density polyethylene
entered the mulch market. The "make it
thinner" approach does have some limitations,
however, so one should also think in terms of
making it last longer. The three-year
greenhouse film, when introduced in the early
1980s, automatically reduced the amount of
plastic needed by one-third. We should
remind ourselves to examine this notion once
in a while instead of pursuing other avenues of
One last thought on landfills. If we
believe a day will come when used plastic will
have some value in recycling, wouldn't it be
wise to create separate landfills just for
plastics. Then we could mine plastics at a later
time when the mother lode had some value!
(Hochmuth, Vegetarian 94-11)
Excerpt from Agricultural Plastics Disposal
Review, Supplement to Agri-Plastics Report,
Vol. 9, No. 2, March, 1994.
B. Reminder on
Sanitization of Packing Lines.
With the fall packing season getting in
full gear we have had several reports of arrival
problems due to decay. Conditions which
promote higher than normal populations of
pathogens on the crops will no doubt continue
for the next several weeks due to the excessive
rain and flooding in South and Central Florida
caused by Tropical Storm Gordon.
Many postharvest decay problems
result from the incorrect use of chlorine for
sanitizing packinghouse dump tanks and
hydrocoolers. In our experience, although
many packers routinely add chlorine to their
water handling systems, the effectiveness of
this treatment in reducing postharvest decay
can be decreased or even nonexistent through
failure to follow the IFAS guidelines for
packinghouse water sanitation. The current
recommendation is constant maintenance
of 100 to 150 parts per million of free
(available) chlorine and a pH in the range
of 6.5 to 7.5 for all recirculated water.
Whenever a product is dumped into water or
washed with recirculated water that is not
maintained under these conditions there is a
good probability that decay problems will arise
during handling and shipping. In this article,
we will briefly outline the principles for
maximizing the benefits of chlorination to
maintain water sanitation.
Pathogens present on freshly harvested
fruits and vegetables accumulate in water
handling systems in which the water is
recirculated, such as dump tanks, flumes and
hydrocoolers. Even healthy looking products
coming in from the field can harbor large
populations of pathogens, particularly during
warm, rainy weather. When fruits and
vegetables are wetted by water containing
pathogens they usually become infected and
subsequently decay during shipping and
The first requirement in maintaining water
sanitation is the addition of an approved
sanitizer to the water, such as sodium
hypochlorite, calcium hypochlorite or liquid
chlorine, to prevent the accumulation of
pathogens. The effectiveness of chlorinated
water as a sanitizer is greatly affected by the
pH of the solution. If the pH is too high, say
above 8.0, the chlorine acts slowly and a
higher concentration is necessary to achieve a
rapid kill of the pathogens in the water. In
contrast, if the pH is too low, say below 6.5,
then the chlorine is too active; it is more
corrosive to equipment and effective chlorine
concentrations are difficult to maintain. In
addition, at recommended chlorine
concentrations and pH levels below 5, chlorine
gas can evolve from the water and create a
hazard for workers, supervisors, etc., working
in the area. Therefore, we recommend that the
pH level of chlorinated water be strictly
maintained in the range of 6.5 to 7.5. All
recirculated water should be changed on a
daily basis, or more frequently if the water
becomes extremely dirty due to build up of
organic matter. Local environmental codes
must be consulted for proper disposal of
The water and form of chlorine used
affect how readily the pH can be maintained in
the required range. Fresh water in Florida may
have a pH above 8.0 due to dissolved calcium
carbonate. The pH of fresh water should be
lowered by the addition of an acidifier, such as
muriatic acid, before the chlorine product is
added. Chlorine available as commercial
strength liquid bleach has a pH above 11.0 and
will steadily raise the pH as it is added to the
water. In contrast, elemental chlorine, a liquid
under pressure, becomes a gas as it enters the
water and acidifies the water. There are
materials available from chlorine suppliers that
will keep the water in the necessary pH range.
The second and also necessary
requirement is to MAINTAIN the free
(unreacted) chlorine concentration at all times
the water system is used. The chlorine
product must be added to the water to replace
the chlorine lost to reactions with organic
matter, chemicals, microorganisms, as well and
the surfaces of fruits and vegetables. There
are several ways to keep adequate chlorine
concentrations. Equipment is available to
automatically measure the free chlorine
concentration and to add a chlorine product to
the water to replace that which is lost to
reactions in the water (known as the chlorine
demand). Moreover, certain types of systems
also automatically maintain the proper pH
range. Other systems feature automated
dispensing of chlorine products, but require
frequent measurement of the free chlorine
concentration to know if the proper amount of
chlorine is being added Managers must be
vigilant with these latter systems because the
chlorine demand can change abruptly, such as
with the addition of product from a different
field, a different grower, or a different field
crew. If free chlorine measurements are not
taken often enough, chlorine levels in the
water can quickly change from adequate to
inadequate causing the product to become
infected with decay pathogens. Manual
addition of chlorine products can be used if the
manager is diligent about taking pH and free
chlorine measurements and making the
necessary adjustments. Samples should be
taken at least on an hourly basis. However, in
our conversations with packinghouse
managers around the state, it appears that
manual water sanitation is usually less than
adequate due to time constraints encountered
during typical packing.
A short comment about the types of
test kits used. Make certain the test kit
measures free chlorine and be very familiar
with the range of concentrations measured.
Swimming pool-type kits usually measure in
the range of 1 to 5 ppm free chlorine. These
kits can provide accurate measurement if the
water sample from the packinghouse system is
diluted to the range of the kit before being
tested. Distilled water should be used to dilute
the sample. If water containing sulfur or
which is contaminated with chemicals or
organic matter is used to dilute the sample
instead of distilled water, then the result will
underestimate the true free chlorine
Other factors which affect chlorine
efficiency include the initial level of inoculum
present on the fruit surface and the exposure
time of the crop in the water. In the case of
tomato dump tanks, the water should be
heated 10F (about 5"C) above the pulp
temperature to reduce infiltration of the water
(and pathogens) into the fruit. More
information is available in the Florida
Cooperative Extension Service Fact Sheets
VC-1," Water chlorination for vegetable
packinghouses" and VC-31, "Tomato
packinghouse dump tank sanitation".
Packinghouse managers must be
vigilant in maintaining sanitized water in
handling systems. By following these simple
guidelines, postharvest decay problems should
be drastically reduced.
(S. A. Sargent, and Jerry A. Bartz, Associate
Professor, Plant Pathology Department,
Gainesville, Vegetarian 94-11).
I11. VEGETABLE GARDENING
A. Florida's Biggest Vegetables -
For those of you who keep up with
who grows the state's heaviest, tallest, or
otherwise largest vegetables, you may be
interested in the following report for 1994 and
We have six new records for 1994.
One of these, okra, is a new world record,
according to Guinness. This is for a stalk of
okra (entire plant length) grown by David
Mikulka of Flagler Beach) Flagler County. A
Guinness World's Records representative
measured the stalk at 19 ft. 10 1/2 inches, from
ground level to the tip of the growing point.
Other records set in 1994 are: lima
bean pod length (8.81 inches), St. Lucie
County; sweet corn ear weight (1 lb 15 oz),
Suwannee County; cucuzzi gourd length (61.5
inches), Hernando County; and yellow
straightneck summer squash (4 lb 1 oz.),
Suwannee County. Note that one gardener by
the name of MacDonald Graham, Suwannee
County, has 10 of the 46 records on file. No
other individual is even close. But there is a
fairly good geographical distribution of record
holders, with 21 counties sharing in the
I wish to thank all of you agents who
help to record these "big veggie sightings".
The general public is always interested in
knowing what is the biggest, as indicated all
the media hype that centers around this
Table 1. Florida's record-size vegetables through 1994.
Bean, Lima (pod)
Collard (plan )
Corn, sweet (ear)
Gourd, cucuzzi (fruit)
Okra, pod (wt)
Okra, pod (length)
Okra, stalk (length)
Potato, irish (tuber)
Potato, sweet (root)
Radish, S. (root)
Radish, W. (root)
Radish, Daikon (root)
Yarn (True) (root)
5 lb. 0 oz.
12 lb. 10 oz.
5 lbs. 4 oz
19 lb. 7 oz.
29 lb. 8 oz.
3 lb. 1 oz.
8 lb. 14 oz.
15 Ib. 6 oz.
1 lb. 3 oz.
13 ft. 3 in.
1 lb. 15 oz.
4 lb. 7 oz.
4 lb. 8 oz.
1 lb. 8 oz.
5 lb. 2 oz.
21 lb. 8 oz.
19 lb. 8 oz.
50 lbs. 0 oz.
7 1/3 lbs.
22 1/4 in.
19ft' 10 1/2"
3 lb. 11 oz.
1 lb. 1 oz.
2 lb. 13 oz.
3 lb. 12 oz.
23 Ib. 5 oz.
131 lb. 12 oz.
23 lb. 12 oz.
2 lb. 1 oz.
25 lb. 14 oz.
10 lb. 8.16 oz.
4 Ib. 1 oz..
18 lb. 4 oz.
12 lb. 15 oz.
(Stephens, Vegetarian 94-11)
Prepared by Extension Vegetable Crops Specialists
Dr. D.J. Cantliffe
Dr. S.M. Olson
Mr. J. M. Stephens
Dr. G.J. Hochmuth
Dr. S.A. Sargent
Assoc. Professor & Editor
Dr. C. S. Vavrina
Dr. D. N. Maynard
Dr. W.M. Stall
Dr. J. M. White