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Title: Vegetarian
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00087399/00347
 Material Information
Title: Vegetarian
Series Title: Vegetarian
Physical Description: Serial
Creator: Horticultural Sciences Department, Institute of Food and Agricultural Sciences, University of Florida
Publisher: Horticultural Sciences Department, Institute of Food and Agricultural Sciences, University of Florida
Horticultural Sciences Department
Publication Date: April 1999
 Record Information
Bibliographic ID: UF00087399
Volume ID: VID00347
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.


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UNIVERSITY OF Cooperative Extension Service
-- FLORIDA oooS--
'" FA Institute of Food and Agricultural Sciences


A Vegetable Crops Extension Publication
floi Hortialtn &Biencea Departme;t P.O. 110690 Gaiesville, FL 32611 Telephone (352)392-2134

Vegetarian 99-04





Sunn Hemp A New Cover Crop For Florida

EAA Leafy Vegetable Phosphorus Fertility Demonstration


"Vegetable Gardening in Florida" soon to be released

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 product.

The Institute of Food and Agicultural Scences is an Equal Employment Opportunty Affirmative Action Employer authorized to provide rseari educational
information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap or national origin


SApril 199

The Vegetarian Newsletter is now
available on the intemet. The website is

Vegetable Crops Calendar

May 18, 1999. 43rd Vegetable Field Day.
Gulf Coast Research & Education Center -
Bradenton. FL. Contact Don Maynard (941)751-

Commercial Vegetables

Sunn Hemp A New Cover Crop in Florida
The scientific name for Sunn Hemp is
Crotalariajuncea L. It comes from the pea family
(Fabaceae or Leguminosae). Common names
are: Sunn Hemp, Indian hemp, Madras hemp,
brown hemp, and sunn. Common variety is
Tropic Sun', released by the University of
Sunn hemp is native to India and
Pakistan. In Southeast Asia sunn hemp has
been grown as a green manure crop for
centuries and now is cultivated in many tropical
regions. Sunn hemp is cultivated in Hawaii,
California and to some extent in Alabama.
Sunn hemp is a tall, herbaceous annual,
with erect fibrous ridged stems reaching heights
up to 7 feet in south Florida. The plant is
covered with short, downy hairs. It's taproots are
long and strong wit many lobed nodules. The
plants branch at about 20 inches above the
ground when not crowded, but branching is
suppressed somewhat in dense stands. In
Homestead the plant's showy bright yellow
flowers bloom profusely in 90 days.
Sunn hemp grows to a height of 6 to 7
feet tall in just ten weeks. No other cover crop is
known to grow so rapidly. In Alabama, sunn
hemp is planted immediately after corn harvest
to prevent erosion of the soil by heavy rains.
Since this plant is a legume, it can fix much of
the nitrogen needed by the next crop. Further,
sunn hemp can be grown as a high-protein
forage for late summer when pastures may

perform poorly. In India cloth, twine and rope are
made from the fiber of older plants. Seeds are fed
to pigs and horses without adverse effects in some
The use of sunn hemp is recommended in
south Florida. This plant serves as an excellent
cover crop in rotation with vegetables. On each
acre, sunn hemp fixes approximately 180 lbs. of
nitrogen and adds 2.5 to 6 tons of organic matter.
It suppresses weeds and reduces root-knot
namatodes, controls erosion and may serve as a
windbreak both for vegetables and for tropical fruit
crops. Seeds germinate readily and seedlings
rapidly produce a thick ground cover. In an
experiment conducted in Homestead, sunn hemp
yielded a total of 7,700 Ibs dry biomass (roots and
shoots) and fixed 182 Ibs N per acre 3 months after
Sunn hemp grows well at mean annual
temperatures from 47 to 820F. Warm
temperatures with moderate humidity are best.
Growth may be slowed by cool seasons, and the
plant is susceptible to freezing temperatures below
280F. Although sunn hemp tolerates poor soil, it's
productivity is enhanced on more fertile soils. Sunn
hemp tolerates soil pH from 5.0-8.4. It is well
adapted for well-drained calcareous soils and for
acidic sandy soils. In order to establish a cover
crop, sunn hemp should be sown at 15 to 40 Ibs.
seeds/acre. The lower seeding rates enable the
plants to branch profusely. Seed should be planted
less than one inch deep. At greater depths the
germination is poor. Seeds can be inoculated with
cowpea inoculant to improve the fixation of
nitrogen. However, in some instances, sunn hemp
without inoculation has grown very well and
developed many nodules. In south Florida, with
adequate soil moisture, the seedlings emerge after
three or four days and form a thick cover. Sunn
hemp is drought tolerant and no irrigation is
necessary during the summer in south Florida.
Nevertheless, in Miami-Dade County the field
demonstration, have shown that irrigation just
before and after seeding improved germination and
Sunn hemp need not be mowed during the
middle of summer. Mowing when the plant is 6 to
12 inches tall produces many lateral branches but
the plants do not recover fully. The plant should be
plowed down when flower buds have formed or
during the early flowering stage. Mowing before
disking and plowing facilitates soil incorporation and


April 1999


decay. For maximum immediate release of
nitrogen to the subsequent vegetable crop, sunn
hemp should be plowed within 60 days, when the
nitrogen concentration is high and decomposition
Whiteflies and thrips can be found on
sunn hemp seedlings during the early summer.
However, no vegetable insects, except
stinkbugs, have been found on mature plants.
Since sunn hemp is resistant to nematodes, it is
advantageous to grow it in rotation with
nematode-susceptible crops. The extremely
rapid early growth of sunn hemp enables it to
shad out weeds very effectively. The sensitivity
of sunn hemp to herbicides has not been
Shortages of seed have prevented sunn
hemp from being grown extensively. Currently
the seed costs $1.50 to $4.00 per pound.
Probably seed production is more difficult in the
subtropics than in the tropics. In the tropics
flowering can begin at six weeks, with maturity
reached at four months or more. Worldwide
seed yields range from 400-900 Ib/ac of seed.
There are approximately 15,000-33,000
seeds/lb. Seeds remain viable for a number of
years. Evaluation of seed production in south
Florida is in progress.

(Li, Vegetarian 99-04)

EAA Leafy Vegetable Phosphorus Fertility
Demonstration Trials
Crop production in the Everglades
Agricultural Area (EAA) is conducted under a
climate of environmental regulation, with a
particular focus on phosphorus (P). The
Everglades Forever Act (1994) requires that total
P (TP) in annual EAA runoff entering adjacent
wetlands be reduced by 25% relative to
"historical" levels. Growers have implemented
BMPs designed to reduce TP levels in farm
drainage waters. These TP levels are comprised
of particulate and dissolved P fractions.
Particulate P fractions range from farm
ditch/canal sedimentary material to flocculent
organic detritus associated with living/decaying
aquatic flora. The dissolved P fraction can
include material originating from fertilizer sources
but also includes a significant background level
from P naturally released during mineralization of
the organic soil matrix. While drainage stream
TP levels reflect contributions from numerous

sources, public perception tends to focus on
fertilizer. This perception is likely fueled by
occasional news reports that oversimplify the
Everglades cleanup discussion by referring to EAA
runoff as "fertilizer-laden", fertilizer-laced", and/or
Within this scenario, EAA leafy vegetable
growers have expressed a timely interest in
pursuing P fertility investigations on popular leaf
crops. Given the recent publication of revised IFAS
organic soil P fertilizer recommendations for
crisphead lettuce (Hochmuth et al., 1994), romaine,
escarole, and endive (Hochmuth et al., 1996),
growers want to conduct verification trials on their
fields, using their current equipment, varieties, and
production practices (liquid fertilizers, etc.). With
this in mind, a series of demonstration plantings
were planned for the 1998 and 1999 growing
seasons with 3 growers using "commercial-scale"
plots on both low fertility (following sugarcane) and
higher fertility (following vegetables) fields. The 2
most popular liquid fertilizer formulations are a 10-
34-0 and an 8-28-0 (basically the 10-34-0 with Mn,
Zn, and B). Applying either source at different P-
input rates was deemed unsatisfactory since N
inputs would also vary which could confound the
interpretation of observed responses. To minimize
N-rate differences, fertilizer blends were formulated
with similar N analyses (10%) but varying in P20,
from 0 to 34%. Micronutrients and K were applied
uniformly across all plots.
Three demonstrations were planted in late-
1998 (Oct. 30 and Nov. 24 at Farm A; Dec. 4 at
Farm B). Tropical Storm Mitch (Nov. 4) washed out
the Oct. 30 planting. At both farm sites, crisphead
lettuce (South Bay 1490) and romaine (Floricos 83)
were planted on raised beds with 36-inch centers (2
rows/bed) and a 12-inch row spacing. Early-season
thinning to a roughly 12-inch plant spacing resulted
in a final stand population of approximately 29,040
Treatments included 5 liquid fertilizer
sources (10-0-0, 10-9-0, 10-17-0, 10-26-0, and 10-
34-0), applied at equal volumetric rates to each
assigned plot. Band-applying sources at 65 and
180 gal/acre at Farm A and B, respectively,
achieved a wide range of P inputs (0, 56, 113, 182,
and 250 Ib PP/Oacre at Farm A; 0, 156, 312, 503,
and 602 Ib P2Os/acre at Farm B). Based on water
extractable soil-test P levels of 13 (Farm A) and 6
(Farm B), revised IFAS recommendations for
crisphead lettuce and romaine were 117 and 175 Ib
P2OJacre for Farm A and B, respectively.

April 1999


Subsequent to planting, the grower
employed standard production practices
throughout the growing season. Plant tissue
samples were collected mid-season and at
harvest for nutrient analysis (data not reported).
Harvested plot area for each commodity was 720
ft2 (120 ft x 2 beds; 480 linear ft) and 540 ft2 (180
ft x 1 bed; 360 linear ft) for Farm A and B,
respectively. At harvest (Farm A Feb. 4; Farm
B Feb. 15), work crews cut and packed plants
into 24-count boxes which were weighed.
Preliminary harvest data are listed in
Table 1. At Farm A, average lettuce and
romaine head weights were fairly similar across
all fertilizer treatments except for the control (10-
0-0). However, the higher P rates (10-26-0 and
10-34-0) supported greater net harvest weights
for both commodities. Total number of harvested
24-count boxes varied across treatments, with
some evidence of increasing box numbers with
increasing P input rates. Survivability and P
fertilization appear somewhat correlated, with a
general trend for greater harvested heads/acre
with increasing P rates. Stronger responses

were observed at Farm B, which initially had a lower
soil-P fertility status and received higher P rates. All
reported response variables (Table 1) tend to
increase with P application. Within the first month
of planting at Farm B, clear differences across
treatments were observed, with poor seedling
survivability associated with the control and lower P
treatments (control, 10-9-0, and to some extent, the
10-17-0). Survivability was likely associated with
extremely low rainfall conditions which prevailed
throughout the growing season (Dec.=0.51 inches
in 7 events; Jan.=2.60 inches in 8 events;
Feb.=0.18 inches in 2 events). Why P inputs might
influence survivability under dry conditions is not
known. Perhaps deeper and more prolific root
systems were encouraged with increasing P inputs,
but this was not measured.
These 2 demonstration trials are exploratory
efforts. Plans for the 1999 season are to include a
third grower and also to conduct trials on low and
higher initial soil-P fertility levels. The EAA leafy
vegetable growers are committed to investigating P
fertility issues and will likely expand these efforts to
include other crops like escarole, endive, red leaf,
and Boston leaf.

Table 1. Romaine and crisphead lettuce harvests under varying P inputs.
Romaine Crisphead lettuce
Fertilize Total Total Total Average Total Total Total Average
r heads 24-cnt net head heads 24-cnt net head
source boxes weight weight boxes weight weight
head/acre box/acre lb/acre Ib/head headlacre box/acre lb/acre Ib/head
Farm A
10-0-0 26696 1112 30179 1.13 23792 991 30170 1.26
10-9-0 26802 1117 39705 1.49 24699 1029 40626 1.64
10-17-0 27785 1158 39882 1.44 23928 997 38129 1.60
10-26-0 27316 1138 42009 1.54 28617 1192 46906 1.65
10-34-0 28753 1198 44856 1.56 26272 1095 42866 1.64
Farm B
10-0-0 15407 642 11966 0.80 15831 660 11369 0.71
10-9-0 16597 692 23568 1.46 15992 666 21249 1.32
10-17-0 19602 817 26433 1.37 22990 958 31041 1.34
10-26-0 25390 1058 32634 1.28 28334 1181 39951 1.41
10-34-0 29665 1236 42001 1.41 28233 1176 41950 1.48
Each mean represents the average of 4 replications.


April 1999

/Die- %&anrmfzmon 0on-n1


Vegetable Gardening

Vegetable Gardening in Florida" soon to be
Finally, after 5 years in the
developmental process, my book, Vegetable
Gardening in Florida, is slated to come off the
press this month or next. Although it was
produced by IFAS, it is being printed by the
University Press of Florida, Gainesville. SP
237 will be offered for sale at
about $16.00 per copy. I believe it will be worth
that small price, as it is filled with colorful
illustrations and photographs ( no black and
whites). The cover is especially attractive and
features IFAS artist Sal Salazar's painting of
the Marjorie Kinnan Rawlings house and
vegetable garden on Orange Lake, at Cross
Creek, Florida. It will be obvious that
Publications chief Julie Graddy and her staff
have contributed much talent into the layout
and design of this book.
As its author, I have put together
information on most every important aspect of
growing a vegetable and herb garden here in
Florida. In so doing, I have utilized knowledge
gained during my 38 years as State Extension
Vegetable Gardening Specialist. This
knowledge comes from my acquaintance with
the results of vegetable studies done by UF-
IFAS and universities in other states, along
with an exposure to gardens located all over
our state.
I am particularly indebted to the
following specialists in supporting departments
for their inputs: Bob Dunn (Nematology), Jerry
Kidder (Soils), Don Short (Entomology), and
Gary Simone (Plant Pathology). We have
purposefully left out chemical pesticide
recommendations so as not to out-date the
publication when these things change so
The following is the Table of Contents:
Chapter 1. Selecting a site. Location,
sunshine, root competition, and soil.
Chapter 2. Planning the garden.
Selecting vegetables, paper plans, succession
planting, companion planting, tools.

Chapter 3. Climatic and weather
effects. Temperature effects, frost protection,
row covers.
Chapter 4. Soil preparation and
management. Your garden soil, soil
preparation, soil pH, liming, high pH soil,
bedding, grow-boxes.
Chapter 5. Garden fertilizers. Plant
nutrients, macro-nutrients, micro-nutrients,
hunger signs, organic fertilizers.
Chapter 6. Using garden fertilizers.
Application amounts and methods, side-
dressing, fertilizing legumes.
Chapter 7. Organic matter. Benefits,
animal manures, plant manures, cover crops.
Chapter 8. Alternative gardening.
Organic gardening, hydroponics, mini-
Chapter 9. Seeding the garden. Use
good seeds, plant tested varieties, seed
treatment, planting the seed, seed storage,
seed longevity.
Chapter 10. Starting with transplants.
Advantages, which vegetables to transplant,
growing transplants, transplanting
suggestions, starting with other plant parts.
Chapter 11. Care of the garden.
Thinning seedlings, cultivation and weed
control, mulching, supporting tall-growing
crops, tomato pruning, watering the garden,
trickle irrigation.
Chapter 12. Insects. Insects that live
in the soil, insects that damage leaves and
fruit, managing insects.

Chapter 13. Diseases. Diseases of
roots and stems, diseases of leaves, diseases
of fruit, disease control.
Chapter 14. Other pests.
Nematodes, birds, rodents, and other animals.
Chapter 15. Pesticides. Application,
sprayers and spraying, pesticide precautions.
Chapter 16. Individual vegetable
crops. Amaranth- yams.
Chapter 17. Herbs in the Florida
garden. Location and soil preparation,
propagation, harvesting and curing, individual
herbs (anise- thyme).
Chapter 18. Harvesting, storing, and
exhibiting. Canning, freezing, storing and
exhibiting produce.

April 1999



Gardening measurements
Varieties guide
Planting guide

(Stephens, Vegetarian 99-04)

April 1999

Dr. D. J. Cantliffe


Prepared by Extension Vegetable Crops Specialists

Dr. T. E. Crocker Dr. G. J. Hochmuth

Professor Professor

Dr. D. N. Maynard


Dr. S. M. Olson


Mr. J. M. Stephens


Dr. S. A. Sargent


Dr. C. S. Vavrina

Assoc. Professor

----- -------------^__ April__1999_

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