July 2, 1975
Prepared by Extension Vegetable Crops Specialists
J. F. Kelly
S. R. Kostewicz
J. R. Hicks
J. M. Stephens
R. K. Showalter
TO: COUNTY EXTENSION DIRECTORS AND A.fTNTS (VEGETABLES AND HORTICULTURE)
AND ROT 1N.'S INTERESTED IN VEGETABLE CROPS IN FLORIDA
FROM: Janes Montelaro, Extension Vegetable Specialist's: /
VEGETARIAN NESLEFTTER 75-7
IN THIS ISSUE:
I. NOTES OF INTEREST
A. Vegetable Extension Specialists--Area Assignments
B. Index for 1974-75 Vegetarian Newsletters
II. C('-P.!FRCTAL 19I:rc -.TAPrl.I' PI'O11CTION
A. Water---HIints on Findiing Good Ouality for Irrigation of
B. Prepare Soil Properly for Best Noaticide Activity
C. Advance Planning to Avoid Common Mistakes Next Season
ITT. HARVESTING AND HANDLING
A. Cooling Tomatoes in Ripening Rooms
IV. VEGETABLE G-CRDFNING
Timely Gardening Topics
Know Your Vegetables Momordica
NOTE: Anyone is free to use the infonnation in this newsletter.
possible, please give credit to the authors.
!11E VEG]pTARIAN NJIVS IAPI'E?
I. NOTIS 01: INTI-Il Si
A. Vegetable Ixtension Specialists --Area Assignments
For some tine it has been evident that we have been unable to adequately
maintain contact with county extension personnel. We have discussed the concept of
assigning area specialists for up to five areas of the state. With two production
specialists, we were unable to even begin this approach. With the return of Dr.
George Marlowe from Vietnam, we are now able to make our first move in the direction
of area assignment. Dr. Marlowe, a regular full-time member of our Vegetable Crops
extension faculty, has been located at the Bradenton Agricultural Research 8
Education Center. This permits us to assign our three vegetable production spe-
cialists primary responsibilities in the counties as indicated on the accompanying
As in the past, the Vegetable Extension Specialists will operate as a team
and each will be available to all counties to fulfill special needs. As such, some
specialists will operate statewide--Jim Stephens to cover gardening and youth pro-
jects and problems, Jim Hicks and Bob Showalter to cover handling and postharvest
problems. Jim Montelaro will exercise leadership in the area of cron fertilization
and pest control, George 'arnlowe in crop varieties, and Steve Kostewicz in weed
control, greenhouse production and rural development. The three area production
specialists will maintain close contact with supporting discipline specialists in
Food F, Resource Economics, Entomology and 'Neatology, Plant Pathology, Agricultural
Fr.Lineering and Soil Science.
By addressing their inquiries to the appropriate specialist, county personnel
can do their part to assure a more oCfective statewide extension program in vegetables
B. Index for 1974-75 Vegetarian Newsletters
We consider our production season for vegetables to be from July 1 to Jun e 30.
;'ith this, the first issue of the new production season, we are enclosing an index
for the twelve monthly issues of the past season (July 1, 1974 to .TJune 3n, 1975).
County Extension Agents wishing to maiaintin a reference file of the Vegetarian
Newsletter should place last season's issues in a folder together with the index.
'.1 .n needed, it is a simple matter to check each annual folder for the material
desired. There are on file in this office indexes for the 1971-72, 1972-73, 1973-
74 seasons, as well as a "catch-all" index for the more important articles spanning
from the early fifties to 1971. These are available upon request from this office.
II. ('O [EICIAL VEGETABLE PPr I HClI N!
A. Water---Hlints on Finding Good Quality for Irrigation of Vegetables
This is the last in a series of three articles dealing with problems related
to irrigation water to be used in vegetable production. The first and second
articles defined water quality and suggested practices which might be used to solve
problems encountered with poor-quality irrigation water. .In this article, we give
some pointers which should prove helpful in the search for best quality irrigation
lPrimary Responsibilities for Vegetable
(Coiiierc ial Agriculture, Production)
Greenhouse and hydroponics
Lettuce f endive
Strainher'r i y
'T IF V'l IT FARIAN I rSW LE'TEiR
nematodes, protecting thamn from the action of the nematicide. The soil should be
i.,'m-lre thoroughly and far enough in advance so that this material can he broken down.
Prior to application, the soil should be of a "seedbed tilth." This helps
by promoting a uniform movement of the nematicide throughout the soil. Large clods,
firmly packed areas, etc., can leave pockets of uncontrolled.nematodes because of
poor penetration of the nematicide into these areas. This can result in rapid
build-up of nanatodes and reduction in crop growth in these areas.
The soil moisture should he at a level as if the area was to be seeded. Too
low a soil moisture allows the nematicide to escape into the atmosphere without
giving adequate exposure to the nanatodes present and poor control will result. Too
high a moisture level will prevent a thorough uniform spread of the nematicide in
the soil and likewise poor control will result. In addition, a cool wet soil will
tend to retain the nematicide longer, increasing the time needed For aeration or
dissipation of the nanaticide prior to planting the cron.
Any pest control material must he used in the proper manner iF desired con-
trol is to be expected. Careful attention or consideration of these factors by
growers before applying nematicides can help increase the effectiveness of the
material they are using. A good control proIram involves doing a good job on all
the factors for obtaining maximum results.
C. Advance Planning to Avoid Common Mistakes Next Season
On numerous occasions over the past years, we advised -vegtable growers to
plan carefully in advance of the production season in order to avoid costly mistakes.
The September, 1972, issue of this Newsletter contained an article entitled "Planning
Before Planting Vegetable Crops." In it, we suggested use of a checklist "as a
general guide to be used in an effort to avoid the more common mistakes made in
vegetable production in Florida." The list is reprinted below.
Checllist of Ttans to Consider in Advance Planning
1. Crop Selection Type, variety,, marketability, competition,
scheduling plantings, weather hazards, pest hazards, etc.
2. Site Selection Land adaptability, weather history, water
supply, water quality, etc.
3. Land Preparation Drainage, irrigation, clearing, leveling,
timing and other amendments.
4. Soil Pest Control Nematodes, insects, diseases and weed
seeds, pesticide residues, etc.
5. Fertilization Land use history, rates, sources, timing,
placement, supplanental applications, microelements.
6. Disease and Insect Control Equipnent, pesticides, residues,
7. Weed Control Herbicides, application equil.iipent and methods,
'11I1 VEGETARIAN NIWSITI'R
8. Harvest and Iandling Scheduling, labor, harvest equip-
ment, grading, packing, marketing, destruction of crop residues.
9. Analysis of Crop Season Correction of mistakes, cost
Since this article'was written, we have noted mistakes in almost every cate-
gory on the checklist. However, mistakes within a few categories appeared more
often than others. In most cases, they could have been avoided with good advance
planning. The five most common mistakes are discussed here as a reminder to vege-
table growers for the coming season.
(1) Liming 'lhe most common mistake was the failure to use lime when it
was needed. We, also, noted probl)es with overliming and poor choice in sources of
limi rn materials.
(2) Fertilization The most co(mnon problem in this cate'.ory was inpro)er
placement. Too often, fertilizer was placed under or too close to the sides of the
crop where it injured plants severely. In addition, use of excessive mounts was
observed quite often. This is not only injurious to the crop, but a waste of
(3) Nematode Control Failure to,properly treat nematode infested soils
was observed to cause many crop failures.
(4) Irrigation Use of poor-quality irrigation water appeared often as a
serious problem in vegetable production. A series of three articles, the last in
this issue of the Newsletter, emphasizes the importance of this problem and .gives
srteo:;tions on how to cope with it. Improper timing of irrigation (especially with
overhead systems) has been observed to be a serious problem, also.
(5) Disease Control Poor scheduling and improper application techniques
have been noted to be equally serious problems in disease control. Errors made in
application techniques involve (1) insufficient and/or poor nozzle arrangement,
(2) excessive delivery pressure, (3) wrong kind of equipment, and (4) wrong time of
day or Ihen too windy.
There are many other mistakes that can be just as costly to the v:getable
grower as the above. lHowever, by pointing out the more common ones, the grower may
be prompted to check every other operation carefully, also.
IIT. IIHARVESTING AND HANDLING
A. Cool i g, TuinI to> in Ripening Rooms
Many of the tomato nackinghouses in Florida have ripening rooms where the
tomatoes are partially ripened before shinning., Proper temperature ma nageiment in
these rooms is extremely important since this is the first step in the ripening
process. A problem created here will be present throughout the marketing process
and will certainly have a bc-aring on the quality of the tomatoes offered 1o the
consumer at retail.
Mature-green tomatoes should be ripened at approximately 200C (-."9i ran;e
650-7fln). Higher temperatures (up to about 26. 50C or 8OF) may result in more rapid
color development, but the Fruit also softens much faster. In addition, d.ciy\- can
'JT IM VEGETARIAN '.T.S LET1HR
be much more serious at hLigher tanperatures. At tanperatures above 300C (8F50,
there is a chance of inhibiting lycopene (red color) development which results in
yellowish fruit. Ripeningi fruit below the reconnended temperature also causes
problems. At 15.5C (60F) coloring is slower, but the fruit may be slightly
finer. Below 10C (50Fl) the fruit softens slowly but will not ripen properly.
Green fruit held at low temperatures prior to ripening are extremely susceptible
Generally, low temperatures in the ripening rooms are not a problem because
the fruit temperature at harvest will be above 10C (5007F). High temperatures are
a problem during periods of hot weather or when the fruit are exposed to the sun
either on the vine or after harvest. Fruit harvested during hot weather will be
close to or above the air toaiperaitui e. These fruit will respire at a ranid rate
and accumulate the heat resulting from respiration. During hot weather, tomatoes
mature faster in the field, resulting in a higher picking volume and capacity load-
ing of the riper-ing rooms. The high pulp temperature, high respiration rate, large
volume of fruit and the high differential temperature between the outside toiipe:.i-
ture and the desired rinening room temperature results in a sizable refrigeration
requirement if the reduction in temperature is to be accomplished in a reasonable
The following information is offered to help derive general guidelines for
Sources of heat:
1. Field heat in the fruit
2. Heat produced hy respiration
3. Heat from cartons, pallets, room air, etc.
4. Heat infiltration through doors, walls, ceiling, etc.
5. Heat produced by fans (or blowers), lights, etc.
Field heat: This.is the amount of heat that must be removed from the fruit
to bring the pulp temperature down to the desired level. Approximately 0.9 Btu is
required to change the temperature of 1 pound of tomatoes I0F. Two examples of the
refrigeration requirement for removal of field heat are given below:
Example 1: A room is loaded with 75 tons (150,000 lbs1 of tomatoes at
a pulp temperature of 8301:. The number of tons of refrigeration (1 ton = 12,0()
Rttu/hr) that would be required to cool the tomatoes to 68F1 (disregard the heat of
respiration) in 1.2 hours is calculated as follows:
150,on0 lbs x n.o (Btu) x 15(830F-68F) = 2,025,000 Btu
2,025,000 Btu/.2' hr = 168,750 Btu/hr
168,75n/12,0nn = 14+ tons of refrigeration for 12 hours
Example 2: A room is loaded with 40 tons of tomatoes at a pulp tempera-
ture of 800T. To cool to 72"F in 24 hrs would require 2 tons of refrigeration.
80,000 x 0. x 8(80nF-72F) = 576,000 Btu
576,000 Btu/24 hr = 24,000 Btu/hr
24,000/12,000 = 2 tons of refrigeration for 24 hours
Respiration heat: An one familiar with tomato ripening rooms knows that the
-ruit produces CO2. It also produces heat by the samLe process. Since the rate of
respiration is dependent on temperature, the amount of heat and C02 produced is
directly related to pulp temperature. Since respiration rate is also dependent on
'TI I V EGETARTAN NIMWSLIETfR
variety, growing conditions, maturity and handling (particularly bruising) estima-
tions oF heat produced. are not precise. At 800F the estimation of refrigeration
needed to remove the heat oF respiration (or to just maintain a constant tempera-
ture) is 0.03 to 0.04 tons of refrigeration per ton of fruit. Using the n.n4 ton
figure for the 75 tons of 830F fruit in Fxample. 1, an additional 3 tons of refrigera-
tion would he needed to remove the heat of respiration (75 x 0.04 = 3.0). Tn
Example 2, if we use the mid range (10.035) for 80F, the requiranent is an
additional 1.4 tons of refrigeration (40 x .035 = 1.4). At 68F the naount of
rceFrigeration required to remove the heat produced by respiration would be approxi-
mately one-half that needed at 8p0-830.
Container heat: In relation to the other sources, the heat from cartons and
pallets is minor and should not in itself create problems.
Infiltration and utility heat: These heat sources depend entirely on design,
constructionH T n--J orlCFTi o i .) tlte 1lrTening rooms and cannot really be generalized.
However, they should he taken into account anytime refrigeration needs are being
calculated. A well constructed and operated room may utilize from 5 to 1WI, of the
refrigeration on heat from these sources. Inadequate design, poor construction or
sloppy :.iiaiia.anient will result in a considerably higher percentage of the refrigera-
tion being used for purposes other than cooling the fruit. It should also he
remembered that the rating on a refrigeration compressor does not necessarily mean
that it will always perform at that capacity under all conditions.
In the two examples given, there is a vast difference between the capacity
needed to cool and that required to maintain 68-700. In fExample t where 75 tons
of fruit are to be cooled from 83F to 680 in'12 hours, approximately 14 tons of
refrigeration are needed to remove field heat. An additional 3 tons are necessary
to overcome resIpiration heat. After the fruit is cooled to 68F, approximately 1.5
to 2 tons of refrigeration would take care of the heat from respiration. Since
heat from other sources would not vary greatly but would have to be taken into
account, a realistic value would be a reduction from about 20 tons required during
cooling to about 5 tons for maintaining the temperature. The change in Example 2
is not nearly so great (from about 5 tons to 2) because of the slower cool down,
smaller temperature differential and smaller fruit load.
A number of tanato operations in the state have each ripening room on an
independent refrigeration system. Tf the system is capable of removing the field
heat in a reasonable time, considerable refrigeration capacity will not be used
after the fruit is at the desired temperature. On the other hand, a unit that is
completely adequate to maintain the proper rinening temperature will not have the
capacity to remove field heat and/or the heat of resni-ration at high temperatures.
Due to the value and highly perishable nature of tomatoes, the feasibility of
independent units is apparent. However, there are alternatives to equipping each
room for ranid cool down.
(1) Pre-cooling room This has been used successfully with vine-ripe
tomatoes For a number of years. Used in conjunction with mature-greens, it would
greatly reduce the demand for refrigeration (and air movement) in the ripening rooms,
and alleviate the temjiperature fluctuations created when warm fruit is moved into a
room with cool fruit.
(2) Booster system Not all ripening rooms will be filled at the same tiue.
A system for utilizing the excess refrigeration capacity from rooms that are at
temperature, in rooms that are cooling, is one .possibility. Another possibility
along this same line would be having central cooling units with a primaiv or second-
ary refrigerant being channeled into any room upon danand.
Tl 1 VEGETARIAN :.11S 'LETi.!R
Activated sludge is inoculated, air-treated and decomposed primary sewage.
Since it is relatively high in nitrogen and free of pathogenic organisms, it is
suitable for use as fertilizer.
To sunmarize, activated sewage sludge is a good source of nitrogen and
phosphorus, some potash and other chemical elements useful in plant nutrition. It
is the only sewage form that can be safely suggested to be used as garden fertilizer.
(3) Timely Topic for week of July 27-August 2.
I have heard about making compost in just two weeks. Is this possible?
The time required to produce a good compost depends upon the type of materials
used, its texture, and the availability of adequate moisture, nutrients and aeration.
It can be made in 14 days if non-woody material is finely ground or pulverized,
kept moist and frequently turned to provide good aeration. By grinding these
materials, decomposition is speeded up because more surface area is exposed to
attack by decay organisms.
(4' Timely Topic for week of August 3-9.
My c(.nmpost pile gets so hot I can feel the heat. Does this sterilize the
As organic compost is decomposing, energy in the form of heat is released.
You can check for heat energy by feel or by reading a -thennrmometer placed in the
interior mass of an active compost heap. Temperatures often reach 170F. This
heat buildup can destroy some disease organisms, insects, insect ec-gs and weed seeds,
but it should not be relied upon to pasteurize the compost. Avoid putting materials
in the compost pile that have detrimental effects. These include diseased plants,
grass and weed seed, etc.
(5) Timely Topic for week of August 10-16.
low can I practice rotation with only a small backyard for my garden?
Ihen planning your garden, try to select a spot where vegetables have not
been grown before or at least for several years. If you don't know the previous
history of the spot, or if you have no choice, plan for and follow a regular rotation
of crops within the plot.. This consists of pl:inting the same kinds of plants in
a different part of the garden each year and in such a way that the sane kind of
plants are not groin in the same spot anymore often than once every 3 or 4 years.
For example, since the tomato, potato, pepper and egtlant all belong to the same
plant family and are attacked by many of the same diseases, do not follow one with
another in the same location.
TT-I \rIEGTARIAN N'i"lT TIER
Vegetable growers often fail to consider surface water as a source for
irrigation. With a little ingenuity and capital outlay, it is possible to develop
a good supply of quality irrigation water in many cases from surface water snurc-es.
The other alternative in Florida is well water,
Well water in Florida can raige from excellent to substandard for purpose
of irrigation. Too often, the only consideration taken into account in digging a
well has been flow (volume) of water.. According to Mr; Dalton.l arrison, University
of Florida Extension Irrigation Specialist, quality of water should receive equal
consideration. The vegetable grower who finds that irrigation water frrm a new well
is "burning" his crop will agree that there is no room for haphazn:rd r in drilling
Mr. Harrison feels that a few simple suggestions should be followed in
pl-annirng a search for good well water. They are as follows:
(1) Study the available information on potential supply, quality, depth,
etc., for well water in the specific areas. Much inFormnation is available on this
subject including chloride contents, dissolved solids, sulfates, hardness, quantities
at different depths, chemical types, etc. 'I1e information is available in map form
at a nominal price from the Florida Board of Conservation, Division of Geology,
Larson Building, Tallahassee, Florida, 32302. With this background information, the
well driller can proceed with more assurance.
(2) If doubt on quantity and/or quality oF water exists, it may be cheaper
to drill a 2- or 4-inch test well first.
(3) The driller should check periodically for volume and quality of water
during drilling of the well. The deepest well may not produce the best irrigation
No one can he assured that satisfactory irrigation water can he found in
every instance. However, we Feel that these suggestions are very worthwhile and
should be given careful consideration by vegetable growers contemplating having
wells drilled in the future.
B. Prepare Soil Properly for Best Neniaticide Activity
The use of nematicides in Florida vegetable production has beconie a standard
practice with most growers. Drastic reductions in yields can be attributed to
uncontrolled populations of nanatodes Feeding on plant roots. Complete eradication
of these pests from a production field is.not economically possible; thus growers
use various means to keep populations to a low irii"ageable level. One oF these means
is the use of a nematicide. The objective with these materials is to reduce the
population to a low level in the treated area. Thus, a crop can develop a root
system and be h.irvested before levels beccome high enough to affect the crown.
Emphasis in previous articles in this newsletter has been placed on such
"application" aspects such as use of plastic mulches, water seals, rate, placement,
etc. Of equal importance are the pre-application considerations such as soil prepara-
tion. These are factors which can affect how thoroughly these materials do the job
when they are applied. Some of the most important to keep in mind are organic
matter, tilth and soil moisture.
Organic matter here is us-ed to denote the green or undecayed plant debris From
previous crops. This residue, if not dealt with, can provide a harboring place for
THIE VEGETAR IAN il'S 1 J'TTER
Proper tenneratures for ripening tomatoes have a bearing on the Final quality%
of the ripened fruit. Excessive refrigeration capacity is expensive. Ti there
are problems in an existing system, check with a good refrigeration engineer on
possible modifications before incurring the cost of additional capacity which may
only partially solve the problem.
1V. VEGETABLE GAPIlNm iN,
A. Timely Gardenin, Topics
These ciues.tions and answers are suggested for agents' use in developing
periodic (weekly) radio or newspaper briefs. They are based on letters of inquiry
front Florida gardeners.
(1) Tin'lely Topic for week of July 13-19.
"'":hnt is causing the ezcgplants in my garden to be rough and lobed instead of
round and smooth?
The problem is widespread having been reported to occur in iiwny areas of the
state, but the cause is not completely understood at this time.
The condition seems to be associated with one variety--Black Beauty. Future
analysis may prove other varieties affected also. Apparently, some unusual environ-
mental condition, or an unusual combination of common conditions, has occurred to
bring about the abnonnal fruit shape. Certainly, we should not discount the possi-
bility of genetically related causes. Chemical injury seems to have been eliminated
due to the widespread occurrence of the problem.
(2) Timely Topic for week of July 20-26.
Is it okay to use city sewage in my vegetable garden?
Many questions arise on the use of municipal sewage for the production of
fruits and vegetables. There is probably less concern when materials are to he used
in soils to produce grass, flowers and ornamentals.
Sewage sludge is a ly-product From the treatment of city sewage. Basically,
there-are three types--raw sewage, digested sludge and activated sludge.
Raw sewace (primary sludge) is a potential carrier of pathogenic organisms,
and is not recommended for use on the soil.
Digested sludge is of different types, but it is settled out and deconpo>.d
in such a way that most of the pathogenic organisms are destroyed. This type, also,
should not be used in the garden.
T1-IE ViF111'ARAN N-FT.SL:ETTER
B. Know Your Vegetables Mtomordica
Three members of the genus Momordica are sometimes encountered in Florida
gardens. These are Chinese cucumber (,CManordica cochinchinensi s), bal sii pear
(Momordica cli-nant ia), and halsam apple (Momordica balsamina). All these cucurbits
ale FTruits oT annual niminj vines, to 10 feet or more, with near round, lobed
leaves. They are much more popular in the Oriental countries such as Malaysia,
Vietnmn and China.
The fruit of the Chinese cucumber is cucumber-shaped, 6-8 inches long, clark
to yellowish-green and very warty (bumpy) on the outside surface. The hollow center
contains several watennelon-shaped, irregularly-etched seeds covered with a scarlet
pulp. The fleshy portion of the fruit is the edible part, mainly cooked in soups.
The balsamn e.i-r is 4 to 6 inches long, oblong, pointed and furrowed lencth-
wise. Wlh'ien fully ripe, it splits into 3 divisions. The immature fruit is hoil.;
as a vegetable. The related balsam apple has a smaller egg-shaped Fruit and i
used in a similar manner. In all cases, production in Florida gardens shlw, l ;
similar to production of cucumbers. Allow 3 to 4 months from seeding to harvest.