J. F. Kelly
J. M. Stephens
R. K. Showalter
G. A. Marlowe, Jr.
TO: COUMY EXTENSION DIRECTORS AND AGENTS VEGETABLESS AND
AND OTHERS INTERESTED IN VEGETABLE CROPS IN FLORIDA
FR4M: James Montelaro, Extension Vegetable S]
VEGETARIAN NEWSLETTER 76-9
IN THIS ISSUE:
I. COMMER1AL VEGETABLE PRODUCTION
A. Checklist of Things to Consider Before Planting Vegetables
B. Pointers for Control of Vegetable Leafminer and Tcmato
C. How Big is an Acre of Tcmatoes?
II. VEGETABLE GARDENING
Timely Gardening Topics
Know Your Vegetables Seedless Watermelons
NOTE: Anyone is
free to use the information in this newsletter.
please give credit to the authors.
COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS. STATE OF FLORIDA, IFAS, UNIVERSITY
OF FLORIDA. U. S. DEPARTMENT OF AGRICULTURE, AND BOARDS OF COUNTY COMMISSIONERS, COOPERATING
UNIVERSITY OF FLORIDA
INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES
VEGETABLE CROPS DEPARTMENT
The VEGETARIAN Newsletter
September 2, 1976
Prepared by Extension Vegetable Crops Specialists
THE VEGETARIAN NEWSLETTER
I. COMMERCIAL VEGETABLE PRODUCTION
A. Checklist of Things to Consider Before Planting Vegetables
Planning for and carrying out things that need to be done before planting is
the first step to success in vegetable production. If only one operation is not
attended to before planting, the crop may be doomed to failure. The number of things
needing attention may vary from time to time. However, all potential preplant require-
ments needed to insure success of a crop should be taken into consideration. In
order to do this, a grower should develop a checklist of things together with a time-
table which will permit carrying them out in an orderly fashion.
Following is a sample checklist and a general timetable which can be used as
a guide in preparation for planting vegetable crops.
(1) Equipment Before the season starts, check equipment to insure that all
are in good operating order. Maintain an adequate supply of critical spare parts.
(2) Irrigation System Growers should check to see that an adequate amount
of water of good quality is available for the crops. This includes checking pumps,
water district regulations, quality (soluble salts), land leveling, ditching, etc.
(3) Drainage System Parallel to the irrigation system, drainage should be
checked to see that water can be removed rapidly. Items to be checked are ditching,
slope, pumps, etc.
(4) Liming Requireents At least two months prior to planting, take a soil
test and lime adequately, if needed.
(5) Crop Residues Five or six weeks before planting, turn under all crop
residues. During this period, maintain soil moisture to permit complete decay of
(6) Land Preparation About three weeks before planting, prepare the soil
for bedding by thorough plowing, disking, harrowing, etc.
(7) Preplant Fertilization Just prior to final bed-shaping, apply fertilizer
to be applied broadcast. Banded fertilizer can be applied during the bed-shaping
operation. Consideration should be given also to sources and rates of fertilizer.
(8) Soil Insect Control Together with preplant fertilization, apply a soil
insecticide for control of wireworms, grubworms, cutworms, etc.
(9) Nematode and Disease Control About two weeks before planting and during
final bed-shaping, apply soil fumigants or other materials to be used for nematode
and soil disease control.
(10) Seed Check seed to insure adequate supply of quality seed. Have seed
tested several weeks before planting if there are any doubts about its germination
Growers with years of experience probably can modify this checklist. The
timetable, presented here as a general guide, can be varied depending on a variety of
factors. What is important is a systematic approach in planning to avoid costly
THE VEGETARIAN NEWSLETTER
B. Pointers for Control of Vegetable Leafmiiner and Tomato Pinworm
Control of the vegetable leafminer and tomato pinworm has been almost impossible
in vegetable crops over the past few years. This is in spite of intensified chemical
control programs. Jim Brogdon, Extension Entomologist with IFAS, suggests that vege-
table growers can lessen the seriousness of this problem by taking a few precautionary
measures. These suggestions are based on research reports published by Poe, Musgrave
Briefly, Mr. Brogdon's suggestions are as follows:
(1) Develop a good sanitation program. This includes destruction of all crop
residues and cull fruit immediately after last harvest. Leafminer and pinworm larvae
buried in the soil cannot emerge easily as adults. Use only transplants that are
free of eggs and larvae.
(2) Destroy host plants in border areas one month before planting.
(3) Use high volumes of water when applying herbicides to soak all mined
foliage where larvae feed.
(4) Do not use insecticides indiscriminately. In many cases, overuse of
insecticides, by killing natural predators, results in higher populations than other-
(5) Try to time application of insecticides to kill larvae in early stages of
development or when moving from one site to another.
These simple suggestions may aid vegetable growers in economically coping with
the problem of leafminer and pinworm control. A good program of monitoring, pending
infestations of either of these two insects, can help in scheduling insecticide
C. How Big is an Acre of Tomatoes?
Several years ago tomatoes were grown in rows 5 to 6 feet apart with plants
spaced 1.5 to 2 feet apart in the row. It was assumed that the plants utilized the
fertilizer and soil moisture in this "feeding zone" of 7.5 to 12.0 square feet per
plant. During this period fertilizer recommendations were based on pounds of fer-
tilizer per acre, a term most growers understood. Plant populations varied from 3,600
to 5,900 plants per acre.
In some tomato-growing areas of Florida, spacing between rows now varies from
4.5 to 12.5 feet. The spacing of plants in the row may vary from 1.5 to 2.5 feet.
Plant populations may vary from 1,400 to 6,400 plants to the "acre". The term acre
is an old term that may have outlived its usefulness, especially in fertilizer
Workers in nematology and weed control consider rate recommendations on the
per cent acre treated. Perhaps we should use this approach in fertilizer recommendations,
An example of the difficulty encountered in the per acre method may be of
interest if we compare several true stories in this growing season.
THE VEGETARIAN NEWSBIETER
Grower A has seep ditches 25 feet apart. Between these seep ditches, he grows
2 rows of tomatoes under plastic. The rows are actually only 36 inches wide, but
the grower considers his spacing to be 12.5 feet apart. In each of these rows, he
spaces his plants 30 inches apart. He states that one row 3,484 feet long is an
"acre", with a plant population of 1,394 plants.
Grower B beds up two rows of tomatoes between seep ditches 18 feet apart. He
figures his "acre" to be 9 feet wide and 4,840 feet long. In this acre he sets 1,940
plants in the full-bed mulch system with in-the-row spacing of 2.5 feet.
Grower C grows his crop in rows 4.5 feet apart with a ditch every seven rows.
The plants, spaced 1.5 feet apart number 6,450 in the "acre" row 9,680 feet long.
Most growers want to achieve high yields in their 2-4 harvests, so they give
serious attention to moisture and pest control and use high levels of fertilizer
(nitrogen 250-300 lbs, phosphate 200-250 Ibs, and potash 350-450 Ibs to the "acre").
In general these amounts are added without much consideration of the plants per acre.
In the full-bed mulch system, the root zone seldom extends beyond the covered
area of 32-38 inches. When 250 lbs of N and 400 Ibs of potash are added to the 1,400
plant "acre", the per plant application is approximately 4.5 times greater than the
6,400 plant "acre".
Growers reason that the "wide row system" saves on labor, provides better
drainage and reduces the need for pruning on the determinate 'Walter' variety. The
functional area of the acre does not change, actually one should consider a three foot
wide row with so many plants per hundred feet of linear row. Preliminary studies by
Dr. C. M. Geraldson, AREC-Bradenton, indicate that these high rates of fertilizer are
justified on the fewer plants per acre because of yield increases per plant at the
Many growers are requesting fertilizer recommendations on Ibs per 100 foot of
raw basis. The following text table may be of value. An application of 250 Ibs of
N and 350 lbs of K20 could be provided by 100 lbs ammonium nitrate 33.5%, 1,290 Ibs
of calcium nitrate 15.5%, and 700 lbs of sulfate of potash (total 2,090 lbs).
Distance Plants Plants/100
between Length of Pounds of per acre ft. row at Ibs. fruit per
beds, ft. bed, feet fertilizer* 2.5 ft 2.5 ft plant, 900 box
O.c per acre' 100 ft/row spacing spacing (30 lb) yield
4.5 9680 20.7 3872 40 6.97
5.5 7920 25.2 3168 40 8.52
6.5 6712 29.8 2785 40 9.69
7.5 5808 34.4 2323 40 11.62
8.5 5125 39.0 2050 40 13.17
9.5 4585 43.6 1834 40 -14.72
10.5 4148 48.2 1660 40 16.26
11.5 3788 52.8 1515 40 17.82
12.5 3484 57.4 1394 40 19.37
*Approximately 2,000 lbs 12-0-18 or equivalent.
It is quite obvious from the above table that the plants in the "wide" rows
are getting much more fertilizer per plant than in the "narrow" rows. The yield
per plant on a theoretical basis would have to increase as shown in the table in order
to have equivalent yields over the entire range of row spacings.
TEE VEGETARIAN NTEWSLETI'ER
Scmeday we may wish to report yield-fertilizer relationships on a per plant
basis. If a grower using 6,000 plants to the acre wished to achieve a 1,300 box
yield (assuming good cultural practices, pest control and moisture control), he
might consider application of the following:
Nitrogen P205 K20
Pounds/plant 0.04 0.02 0.06 -
Grams/plant 19.07 7.26 26.33
Pounds/acre 250 100 350
There are many ways to express fertilizer reccauendations such as pounds per
acre, pounds per linear foot of bed, or pounds per plant, each having advantages and
disadvantages. Perhaps a uniform method is not likely with the wide range of row
pacings and plant popu nations used today. We should, however, carefully consider
the placement, plant population, potential salt problems, desired yield level, and
cost-benefit of fertilizer to be applied in this intensive full-bed mulch culture.
III. VrGETABLE GARDENING
A. Timely Gardening Topics
These questions and answers are suggested for agents' use in developing periodic
(weekly) radio or newspaper briefs. They are based on letters of inquiry from Florida
(1) Timely Topic for Week of September 19-25
I don't seem to have any luck growing garlic here in Florida, what could be
Garlic is sensitive to such environmental factors as length of day and tempera-
ture. It is started by planting the cloves (parts of the bulb). After harvest, these
cloves go into a period of dormancy. Storage of these cloves at around 400F will
start the sprouting process. Then, they should be planted for early growth during
cool days around 680. Following this wintertime growth in Florida, bulbing should
take place as the days get longer in the spring and early summer. Higher temperatures
during this bulbing period are not detrimental but dry weather near and at harvest
time is needed for a yield of high quality bulbs. Any breakdown in the sequence out-
lined, in addition to many other factors, could be responsible for your disappointments
with this crop.
(2) Timely Topic for Week of September 26-October 2
I have a bad nutgrass problem in my garden and am wondering if mulching will
take care of it.
THE VEGETARIAN NEWSLETTER
Mulching with dead plant material or plastic will do little good to suppress
the nutgrass. These mulches are easily pierced by the growing point of the nutgrass.
It then has a competitive advantage over other weeds which are not able to grow
through the mulch. Even though the mulch would not thwart the nutgrass, it still
should be applied. The mulch would lessen the competitive effects of the nutgrass.
For example, sufficient soil moisture and fertilizer would be conserved for both
the weed and the crop plant.
(3) Timely Topic for Week of October 3-9
I understand that the fall is the best time of the year to start my strawberry
planting in my garden. How can the plants withstand the cold winters even here in
The varieties of strawberries grown in Florida are short-day varieties. Plants
are set in the fall. During the cool, short-days of winter, flowering is initiated.
Berries formed during the cool winter months quickly mature as days become warmer
and longer in the spring. In the event of frost or freezing temperatures, the plant
leaves, stems and roots are not damaged, but such tender parts as flowers, flower buds,
and fruits may be injured or killed. The degree to which the parts are injured is
affected by such things as (1) the duration and rate of temperature drop, (2) the
condition of the plant, and (3) the variety grown. Frost protection techniques, such
as covering the plants with heat-loss barriers, are helpful in producing an early crop.
However, even with early losses due to frost, all areas of Florida may expect suitable
yields during the frost-free months of March, April and May.
(4) Timely Topic for Week of October 10-16
I read a gardening article on cucumbers the other day which several times
mentioned the term "gynoecious" in reference to hybrid varieties. What does this term
The standard common cucumber plant is called monoecious, having similar numbers
of both male and female flowers on the same plant. Of course, it is the female flower
that develops into the fruit following pollen transfer from the male flowers (via bees).
A gynoecious hybrid has mostly female flowers, and thus a potential for a much higher
number of fruits than standard varieties. The problem is how to get the female flowers
pollinated when there are only a few male flowers present. The answer is to mix seeds
of a monoecious variety into the seedbag containing seeds of the gynoecious variety.
In actual practice, the commercial seedsman does this before selling the seed. Usually
the mix (called a blend) is somewhere around 10-15% monoecious and 85-90% gynoecious.
THE VEGETARIAN NEWSLETTER
B. Know Your Vegetables Seedless Watermelons
Seedless watermelons are sterile hybrids that develop fruits, but no seeds.
The seeds for growing them are produced by crossing a normal watermelon with one that
has been changed genetically by treatment with a chemical called colchicine (pro-
nounced kol-chi-seen). The seed from this cross produces seedless plants which, when
pollinated with pollen from normal plants, produce seedless melons.
In seedless watermelons, rudimentary seed structures develop. These are small,
soft, white, tasteless, undeveloped seedcoats that are eaten right along with the flesh
of the melon.
A scientist named H. Kihara, of Kyota University, Japan, developed the
technqiue for producing seedless watermelons. He reported his procedures in 1950.
Here is a more technical version of the above explanation.
The normal watermelon (called a diploid) has 22 chromosomes per cell. By
treating seedlings with colchicine, a new plant type called a tetraploid having 44
chromosomes is produced. Then, by crossing a tetraploid (44 chromosomes) with a
normal diploid (22 chromosomes) as the pollinator, one gets a triploid (33 chromosomes).
This triploid seed produces a sterile hybrid which will not reproduce itself (much like
the mule and the banana). When flowers of this sterile triploid plant (called the
seedless watermelon plant) are pollinated by a normal plant, seedless fruits develop.
Due to the entire hand-oriented process, the resulting seeds are expensive.
Therefore, much care should be given to the culture of the seedless watermelon crop.
For this reason, seedlings should be started in peat pots or other suitable transplanting
containers. From then on, culture is similar to that for regular watermelons.