INSTITUTE OF FOOD AND
UNIVERSITY OF FLORIOA
A Vegetable Crops Extension Publication
Vegetable Crops Department 1255 HISPP Gaincsville. FL 32611 Telephone 392-2134
October 15, 1990
S I. NOTES OF INTEREST
SB. New Publications.
II. COMMERCIAL VEGETABLES
A. Evaluation of the Potential for Garlic Production.
/ B. Cucurbit Variety Evaluation, Leesburg CFREC, Spring
C. Vegetable Transplant Plug pH ... Some Thoughts.
III. VEGETABLE GARDENING
A. Manual of Minor Vegetables Let's Sell It.
B. ClandoSan as a Nematicide.
C. Garden Soil Testing Changes
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
1 constitute a recommendation n of the product.
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, or national origin.
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L NOTES OF INTEREST
A. Vegetable Crops Calendar
October 26-29, 1990. National
Junior Horticultural Association Con-
vention. Green Bay, Wisconsin.
November 4, 1990. National
Cucumber Conference, Holiday Inn,
November 4-8, 1990. American
Society for Horticultural Science. Tucson,
November 13, 1990. Southwest
Florida Research and Education Center
Immokalee. Vegetable Field Day and
November 27-29, 1990. Commercial
vegetable program planning meeting for
County faculty. West Palm Beach.
December 17-19, 1990. Florida
State Horticultural Society Convention.
Grosvenor Resort Hotel, Lake Buena Vista,
B. New Publications
G. Elmstrom and A. Chandler, 1990.
Cucurbit Variety Evaluation. CFREC
Research Rpt. LBG 90-15.
C. S. Vavrina and K A. Armbrester,
1990. Propel: A Biostimulant for Vegeta-
bles; Tomato Trial. SWFREC Report IMM
C. S. Vavrina and K. A Armbrester.
1990. Transplant Anomalies: Watermelon
"Rat-Tail" Phenomenon. SWFREC Report
IL COMMERCIAL VEGETABLES
A. Evaluation of the Potential
for Garlic Production.
Garlic, Allium sativum L., is a
bulbous plant related to onion, chive, and
leek. Garlic bulbs are somewhat smaller
and more angular than those of onion.
The mature bulb is made up of several
segments, called cloves, that are encased in
a common scale which accounts for the
angular bulb shape. The cloves are used
for propagation as well as for food.
Although the size and growth habit of
garlic and onion are similar, garlic leaf
blades are thin and solid whereas onion
leaves are tubular. Because of its strong
flavor and pungent odor, garlic is used as a
seasoning for other foods rather than as a
Garlic is an important world crop.
In 1988, production occurred on 1,127,000
acres, average yields were about 56 cwt/
acre, and the total crop exceeded 3 million
tons. The leading garlic producing coun-
tries were China, Republic of Korea, India,
Spain, and Egypt. U.S. production, mostly
in California, was on over 12,000 acres,
with average yields of about 134 cwt/acre,
and a total production of 77,000 tons. In
the 1979-81 period, the last year that
USDA data were available, the California
crop was valued at $32.5 million annually.
There is no commercial garlic
production in Florida, however, inquiries
frequently are received from prospective
growers on the feasibility of garlic
production here. The purpose of this
evaluation was to make a preliminary
assessment of crop management practices
'California Early' (CE) and
'California Late' (CL) garlic was obtained
from California for propagating stock. The
bulbs were divided into individual cloves
and planted 4 inches apart in double rows
on raised beds in mid-November. The beds
had been fertilized with 2.5-2.2-2.6 lb N-
P2O8-K20 per 100 linear bed feet from
soluble and slow release fertilizer. The
fertilizer was incorporated in the bed
before final pressing, and the crop was seep
The aerial portion of the crop
appeared normal and vigorous throughout.
The 'CE' garlic was harvested in early May
when most of the tops were dead. The
'CL' garlic was harvested in late June even
though the tops were still green. The tops
were clipped and the garlic was dried in a
well-ventilated greenhouse. Total yields of
'CE' were about 5000 lbs/A and only about
700 lbs/A from 'CL'. Marketable yields
were less than 2000 lbs/A for 'CE' and nil
Yields in California averaged 128
cwt/A during the 1979-81 period compared
to the 19 cwt/A obtained in this trial from
'CE'. Even the total yield of 53 cwt/A in
this trial did not approach the yields
obtained in California. One cause of the
low yields may have been because of inad-
equate plant populations. In California,
beds are on 40-in. centers and plants are
spaced 1 to 3 inches apart in double rows
on the bed. Accordingly, plant populations
in California range from about 105,000 to
314,000 plants per acre whereas plant
population in this experiment was only
about 52,000 plants per acre.
The low percentage of marketable
'CE' bulbs and total lack of marketable 'CL'
bulbs may have been related to storage
temperature used for the propagating
stock. Research has shown that garlic
bulbs stored at 32 to 41fF produced bulbs
that were not fully encased in an external
scale, and this was typical of bulbs from the
'CE' planting stock which had been in-
tended for market. Planting stock stored
at 59 to 68*F produced plants that failed
to produce bulbs and whose tops remained
green, and this response was typical of the
'CL' garlic in this experiment.
Additional research will be required
to address the questions raised in this
study, and to determine the feasibility of
commercial garlic production in Florida.
Commercial production cannot be recom-
mended from the results obtained in this
(Maynard Vegetarian 90-10)
B. Cucurbit Variety Evaluation,
Leesburg CFREC. Spring 1990.
This is a brief summary of evalua-
tions on the following kinds of cucurbits:
cantaloupes, honeydews, summer squash,
winter squash, seeded and seedless water-
melons. Results of only the replicated
trials are included, and only those varieties
are listed with highest total marketable
Cantaloupe, green flesh/honeydew
Highest marketable yields: Red
Ace, Cruger, Volga, Tenkei, Emerald Pearl.
Cantaloupe, netted, orange flesh
Highest marketable yields: Nova,
Goldmark, 85M104, All Star, Primo, Tasty
Sweet, Westar, Hy-Mark.
Summer squash, green (Replicated)
Highest marketable yields:
Zucchini, NUN 6661, Congress,
9715, XPH 1630, Senator.
Summer squash, yellow (Replicated)
Highest marketable yields: Sunbar,
835233, Dixie, Precious, SF28-6, Goldie.
Winter squash, acorn (Replicated)
Highest marketable yields: Seneca
Autumn Queen, Cream of the Crop.
Winter squash. Buttercup (Replicated)
Highest marketable yields:
Toughman No. 12, Toughman No. 13,
Winter squash, Butternut (Replicated)
Highest marketable yields: Ultra,
Early Butternut, Zenith, Butterbush.
Mini-pumpkin (only one tried Jack-Be-
Watermelon. Icebox (Replicated)
Highest marketable yields: Tiger
Baby, Mickylee, NUN-1652, Sugar Delicata,
Baby Gray, Minilee.
Watermelon, seeded (Replicated)
Highest marketable yields: Mirage
LS, Early Jubilee, Royal Star, Jubilee, XPH
6004, Charleston Gray, Regency.
Watermelon, seedless (Replicated)
Highest marketable yields: HMX
7924, Crimson Trio, CFREC 89-11, CFREC
90-2, Supersweet 5032.
Editor's note: These were the top per-
formers in the variety trials planted or
transplanted in March, 1990, at the Central
Florida Research and Education Center,
Leesburg as reported by Gary Elmstrom
and Annette Chandler in Leesburg CFREC
Research Report LBG 90-15, Cucurbit
Variety Evaluation. More complete infor-
mation is in this report, available from the
(Stephens, Vegetarian 90-10)
C. Vegetable Transplant Plug
pH ... Some Thoughts.
Prompted by a question from a
Pennsylvania Extension Service vegetable
specialist about whether a Florida
vegetable transplant plug pH of 8.2 was
unusual, we quickly surveyed 4 convention-
ally-irrigated transplant houses and 1 ebb-
and-flow house in southwest Florida. The
average pH ofa "finished" (6 weeks) tomato
transplant plug was 7.8 (range 7.4 8.0).
One would think such a plug pH could
hamper the uptake of some elements such
as P and micronutrients. Iron chlorosis has
in fact been documented in one case within
the last year. But, by and large, the plants
seem to do quite well in this soil environ-
What is the reason for this pH rise?
In general, three factors are at work. First,
most well water in Florida is high in
bicarbonates, both calcium and magnesium.
As relatively insoluble products, these
materials can build-up in the soilless plug
as nutrients and water are withdrawn via
evapotranspiration. The subsequent build-
up leads to a higher pH.
Second, the uptake of nitrate
results in an alkaline medium, and in the
small volumes associated with a vegetable
transplant plug this factor also contributes
to the problem.
Third, most transplant houses use a
fertilizer blend that is at least partially
urea-based. The reduction of urea to
ammonia can lead to an increase in pH.
Urea combines with water to form ammo-
nium carbonate (NH4)2CO3 which further
reacts with calcium to form calcium carbo-
nate and ammonium. Calcium carbonate is
immediately recognized as a base (ie.
Acid-forming fertilizers should not
be relied upon to reduce transplant plug
pH should you see a problem. The best
way to neutralize excess bicarbonates in
irrigation water is through acidification.
Kidder and Hanlon provide a thorough
treatise on the acidification process and
management in Notes in Soil Science #18,
Some transplant houses regularly
acidify (usually phosphoric acid) the water
to reduce a high pH and also to help clean
the lines. However, research at the
SWFREC has shown soulless mixes with a
beginning pH of 6.2 6.5 even when
watered with well water acidified to pH 5.5,
can rise, over a period of 4 6 weeks, to 7.2
or greater. Should no problems arise, the
acid will render such elements as Fe, Mn,
and Zn more available for uptake by the
While a plug pH above 7.5 may con-
cern the receiver it has it's advantages also.
According to J. P. Jones, Plant Pathologist
in Bradenton, such plug pH's will insure
the Fusarium Crown Rot organism will not
be present in the transplants!
(Vavrina, Vegetarian 90-10)
m. VEGETABLE GARDENING
A. Manual of Minor Vegetables -
let's sell it.
The publication SP-40, "Manual of
Minor Vegetables" is one of the very first
publications IFAS has offered "for-sale" to
the public. In the 2 years since its release
(Oct. 1988) several hundred copies have
been sold in every Florida county and every
state in the U.S. Even so, sales have
started to slow down, and we need to start
them moving again.
Why are sales important? If IFAS
expands its "for-sale" publications, obviously
the publications must sell in order to
regenerate funds for additional publica-
So, what about Manual of Minor
Vegetables? I'm convinced it has infor-
mation well worth the $3.00 asking price.
You agents refer to it all the time answer-
ing questions about little known vegetables.
But no county office that I have seen is
displaying the publication for the public to
see and purchase a copy.
Therefore, I'm asking that each
Extension office display an office copy and
the promotional sheet that was prepared
for the publication. Then when someone
asks about buying a copy, the office staff
can give them a copy of the order blank.
Also, when you run a copy of one of
the pages in response to a question, I
suggest you accompany it with a copy of
the order blank.
Each county office was provided a
copy of the publication when it first came
out. It may be that we need to get your
front office another copy for display. If you
need help on this, please contact me. We
sure appreciate your help in getting this
publication to the people, and in return,
getting back some of the cost so we can
complete the 'Vegetable Gardening in
Florida" for-sale publication currently
(Stephens, Vegetarian 90-10)
B. ClandoSan as a nematicide.
A lot of you agents may have missed
an article by Bob Dunn, our Extension
Nematologist, on the status of ClandoSan.
I want to bring this report to your atten-
tion due to the lively interest gardeners
have shown in this product as a possible
Here's what Bob had to say about it
in the Florida Master Gardener News, Vol.
3 No. 3, Sept. 1990.
"One of the subjects about which
Master Gardeners ask me most frequently
is whether ClandoSan and similar products
are truly effective as nematicides. Since it
was patented in 1987, ClandoSanR618 has
been widely publicized as a nematicide that
can be used on any crop without danger to
the user or the environment. It was regis-
tered by the U.S. EPA and 49 of 50 states
with unprecedented speed because of its
lack of toxicity. It is also registered in
Florida as a fertilizer because of its
substantial nitrogen content. Many other
products offered as "non-toxic" nematicides
by various vendors of products for organic
gardeners are the same preparation with a
different name on it. If a product contains
the same ingredients, it is almost certainly
ClandoSan by another name.
THE PRODUCT. ClandoSan 618
is a mixture of processed chitin-rich
material (e.g., shrimp or crab shell), urea,
and an organic carrier and diluent (gener-
ally soybean meal). It was developed at
Auburn University tests as an alternative
to soil fumigation for home vegetable
gardeners. At least two modes of action
are hypothesized but not yet proven. First,
natural degradation of each of the three
components is believed to generate meta-
bolites that are toxic to nematodes.
Second, each component is believed to act
as a "selective medium" that encourages
growth and proliferation of microorganisms
that are natural enemies of nematodes. It
is interesting to note that the product
contains approximately 10.4% nitrogen:
about 4.6% is readily available as urea; the
remaining 5.8% mostly slowly available,
comes from the chitin and grain compo-
ClandoSan 618 came to commercial
production because of favorable results in
tests against root-knot nematodes in
vegetables and ornamentals in pots in a
greenhouse and in small field "microplots".
Those results were obtained from situa-
tions in which the product was physically
mixed into the soil (before potting, in
greenhouse tests; applied to surface and
tilled into the root-zone for microplot
tests). Incorporation maximizes the oppor-
tunity for the soil microflora to reach and
utilize the material. There has been little
formal study of these products for nema-
tode control in Florida's sandy soils, but
they may offer some relief from root-knot
nematodes if applied as suggested by the
manufacturer and uniformly mixed with
the soil at least a week before planting the
Although the company had no data
to indicate that the product would
effectively control nematodes in turf by a
surface application, they did encourage its
use for that purpose. Unfortunately, there
was little or no nematode control from sur-
face application of ClandoSan to turf in five
experiments conducted on St. Augustine-
grass, bermudagrass, centipedegrass, and
zoysiagrass during the 1988 growing sea-
son. Strong growth responses seen at first
on all four turf species faded quickly after
4-8 weeks, and could be attributed entirely
to the nitrogen fertilizer content of the
product. Serious bright chlorosis (yellow-
ing) was often seen in bermudagrass and
centipedegrass that had been treated with
ClandoSan, as soon as the readily-available
nitrogen was gone.
In essence, then, ClandoSan and
similar products may provide some
nematode control by encouraging growth of
beneficial microorganisms in the soil when
they are incorporated uniformly into the
soil before planting. They afford no pro-
tection to turf (or, presumably, any other
crops) when applied to the surface without
physical incorporation; the only component
that can be "watered in" is the urea, which
can be obtained much more cheaply. The
amount of nitrogen that is applied is far
above that which is recommended for good
plant (turf or vegetable) growth, and may
be enough to become a serious environ-
mental pollutant. Most gardeners have
available to them many good free or very
inexpensive sources of organic soil
amendment materials that will do about
what these expensive products are sup-
posed to do. Using locally-available organic
soil amendments also enables gardeners to
avoid the environmentally objectionable
over-use of nitrogen fertilizer. Gardeners
should also keep in mind that, although it
is not a traditional pesticide, ClandoSan
hardly fits anyone's definition of an
"organic" gardening material: it contains a
substantial amount of urea, which is
manufactured from petroleum or natural
(Stephens, Vegetarian 90-10)
C. Garden Soil Testing
This is to call your attention to the
letter each county director relieved from
Ed Hanlon about new costs and forms for
the Extension Soil Testing Lab (ESTL).
The new Vegetable Garden Information
Form is IFAS Form 2674 (Revised Aug. 90).
Beginning October '90, Ed's lab will be
accepting only the revised form and the
new charges. The ESTL will call clients
and delay sample results if the correct
payment does not accompany the samples.
The new charges are as follows:
Standard Fertility Test (for pH, lime, P, K,
Ca, Mg) $5.00.
Soil pH and lime test $2.00.
Remember that the code for a vegetable
garden is 90. For other test charges, such
as water and salts, be sure to check Ed's
(Stephens, Vegetarian 90-10)
Prepared by Extension Vegetable Crops Specialists
Dr. D. J. Cantliffe
Dr. D. N. Maynard
Dr. W. M. Stall
Dr. G. J. Hochmuth
Dr. S. M. Olson
SProfessor and Editor
Dr. J. M. White
Dr. S. A. Sargent
Dr. C. S. Vavrina