'"Fertilization Characteristics of
Wholesale Container Woody
Ornamental Nurseries in Florida
Thomas H. Yeager, William J. Foster,
and William R. Summerhill, Jr.
MAR 18 1987
University ot hlorda
For Commercial Use'"Only
Florida Cooperative Extension Service
Institute of Food and Agricultural Sciences
University of Florida / John T. Woeste, Dean
Fertilization Characteristics of Wholesale Container
Woody Ornamental Nurseries in Florida
Thomas H. Yeager, William J. Foster, and William R. Summerhill, Jr.
TABLE OF CONTENTS
Introduction .......................................................... .............. 1
Survey Design and Data Analysis
Survey Characteristics ................................................................ 1
Data Classification/Analysis ............................................................ 1
Data Calculations .................................................................... 1
Method of Application .................................................................2
Fertilizer Distribution .................................................. ............ .. 2
Fertilization Characteristics ................ ...........................................2
Significance to the Industry
................. .................... .......................3
Thomas H. Yeager is Extension Ornamental Horticulturist, William J. Foster is a Graduate Assistant, and
William R. Summerhill, Jr. is Extension Program Specialist. All are with the Institute of Food and Agricultural
Sciences, University of Florida, Gainesville.
Fertilization is an important cultural aspect of
woody ornamental production; however, limited infor-
mation exists on the fertilization practices of container
nurseries in Florida. The vast array of fertilizer
analyses makes it possible to apply a wide range of
macro- and micronutrients to optimize medium condi-
tions. The various methods of application allow the
nursery operator to choose a specific method that best
fits the size of the nursery, environmental conditions
and plants produced.
This survey was conducted to characterize fertiliza-
tion practices of wholesale woody ornamental con-
tainer nurseries in Florida. Data were collected on con-
tainer size, containers per acre, nursery acreage, fer-
tilizer application methods, rates, frequencies, brands,
analyses, as well as the amount of labor required per
application. The results will be useful for extension
program direction as well as benchmark data for
future evaluations of program impact.
Survey Design and Data Analysis
Data for this study were obtained from nurseries in
24 Florida counties (Table 1). The Division of Plant
Industries identified from their inspection list a total
of 150 nurseries that met the following criteria:
wholesale operations with 30,000 or more shrubs.
County extension faculty were supplied with names
and addresses of nurseries to be surveyed in their coun-
ty and survey forms (Appendix) which were subse-
quently mailed, hand-delivered or completed by per-
sonal or telephone interview. Survey forms were to be
completed only by those nurseries having more than 1
acre of 1-gallon or larger size shrubs. Fourteen
nurseries were omitted because of the acreage require-
ment or for various other reasons. Seventy-eight com-
pleted survey forms were returned (57% response).
Since those nurseries responding do not represent a
random sample of the total population of nurseries, few
statistical inferences can be made. Although the data
may not be general to the population of nurseries, they
are thought to provide substantive insight as to the
fertilization practices of the nursery industry.
The primary focus of the survey was fertiliza-
tion application methods. Four methods of fertilizer
application were categorized as follows: broadcast
(BDR), topdress (TDR), incorporation (INC), and liquid
(LIQ). Survey forms were designed to obtain applica-
tion information by container size.
For a particular container size, nurseries responding
could have used more than one method of application,
and more than one type of fertilizer with the same
method. For this reason, most of the results are given
as frequencies. The frequency represents the number
of times a particular method was used by all nurseries.
When at least one or more responses changed (con-
tainer size, application rate, applications per year,
brand, analysis, etc.) within a given method, it was
counted as another use of that method and added to the
frequency. Therefore, frequencies were used to provide
insight as to the extent a particular method was used.
The various rates, quantities, etc. of fertilizers were
calculated on a container basis. Appropriate applica-
tion rates per container were calculated and were con-
verted from teaspoons, tablespoons and ounces to
pounds with either a specific conversion factor for a
particular brand of fertilizer or an average conversion
factor for other brands of fertilizer. The percentage of
nitrogen is expressed as N, the percentage of phos-
phorus as elemental P (P20, x 0.43642) and the percen-
tage of potassium as elemental K (K20 x 0.83015).
Table 1. County and number of plants surveyed within
County Surveyed Plants
Palm Beach 515,050
St. Lucie 103,572
Santa Rosa 92,995
Total plants surveyed 30,827,677
Total population (136 nurseries) 42,181,689
The average nursery was 16.5 acres and grew
primarily 1- and 3-gallon plants. The averages for the
number of containers per acre were 10,839 for 1-gallon,
4,485 for 2-gallon, 3,302 for 3-gallon, 1,000 for 4-gallon,
500 for 5-gallon and 1,015 for 7-gallon. The county and
number of plants within the counties surveyed are
presented in Table 1.
Method of Application
Eighty-three percent of the nurseries responding
topdressed fertilizer, 51% incorporated, 21% used
liquid and 12% broadcast. Based on frequency of
methods of application, topdressing and incorporating
fertilizer were the most often used (Table 2). The
number of times a method was used within each con-
tainer size is shown in Table 3.
Topdressing was the major method of fertilization for
1-, 3-, 4- and 7-gallon containers, closely followed by
incorporation. Incorporation was the major method of
fertilization for 2-gallon containers. No 6-gallon con-
tainer plants were reported for the nurseries surveyed.
Of the containers with fertilizer incorporated in the
media, 65% had the fertilizer mixed at the nursery as
opposed to purchasing premixed media. Only 10% of
the liquid fertilization frequency was used with a drip
system and all were 7-gallon containers. Based upon
frequency of response, broadcasting and topdressing
were applied six and four times a year, respectively,
while liquid was applied once a week.
Fertilizer distribution statistics were computed for
each size container (Table 4). Average yearly pounds of
fertilizer in the container (Pot), pounds of fertilizer
waste (Waste) or fertilizer applied but not in container,
pounds of nitrogen (N), phosphorus (P), potassium (K)
in the container, minutes of labor per container (Labor)
and total number of applications per year (App) were
Topdressing 1-gallon containers used 40% less total
fertilizer than liquid and 30% less than broadcasting,
yet provided 271% and 729% more fertilizer per con-
Table 2. Number of times methods were indicated on
survey forms (all respondents).
Table 3. Number of times methods were indicated on
survey form by container size.
Method of Application
Size (gal) BDR TDR INC LIQ
1 9 73 44 13
2 2 9 10 3
3 6 75 42 13
4 0 4 1 0
5 0 1 1 1
6 0 0 0 0
7 0 27 12 6
trainer (Pot) than liquid and broadcasting, respectively.
Topdressing 3-gallon containers provided 302% and
632% more fertilizer per container than liquid or
broadcasting, respectively. The amount of fertilizer per
container also increased 229%, 272%, 168% and 191%
for broadcast, incorporation, liquid and topdress,
respectively, from the 1- to 3-gallon containers. The
data indicate no waste of fertilizer with topdressing
and incorporation. Broadcasting was the least efficient
method for fertilizing 1-gallon containers with 90%
waste of the applied fertilizer.
Labor requirements increased for broadcast, incor-
poration and topdress when going from a 1-gallon to a
3-gallon container, although the numbers of applica-
tions were similar. Topdressing was generally the most
labor intensive method, while liquid fertilization and
incorporation were generally the least laborious.
The two most common fertilizer analyses used for all
methods were 20-4-10 and 6-6-6 comprising 8% and 6%,
respectively, of the total number of responses. The two
most common fertilizer analyses with methods used
are presented in Table 5. Scotts and Osmocote were
the two most common fertilizer tradenames used
representing 13% and 9%, respectively, of the total
frequencies. Fifty-one percent of the respondents
indicated fertilizer costs were very important.
However, 63% of the respondents were not monitoring
media soluble salts, an indicator of adequate fertility.
Topdressing was the most frequently used method of
application followed by incorporation. One-gallon con-
tainer plants were topdressed at a yearly rate of 0.0171
pound (7.76 g) of N, 0.0034 pound (1.54 g) of P and
0.0087 pound (3.95 g) of K per container. The 3-gallon
plants were topdressed with 0.0476 pound (21.59 g) of
N, 0.0097 pound (4.40 g) of P and 0.0234 pound (10.61 g)
of K per container. Topdressing 1-gallon containers
used 40% less fertilizer than liquid and 30% less than
broadcasting, yet provided 271% and 729% more fer-
Table 4. Average yearly fertilization statistics by con-
tainer size and method.
BDR INC LIQ TDR
No data 0.394
No data 0.317
tilizer per container than liquid and broadcasting,
respectively. Topdressing 3-gallon containers provided
302% and 632% more fertilizer per container than
liquid or broadcasting, respectively. Topdressing
1-gallon and 3-gallon containers was done an average
of five times per year taking 0.22 and 0.31 minutes,
respectively, of labor per container. Fertilizer waste
for all container sizes was highest among broadcast
and liquid applications; thus, topdressing and incor-
porating fertilizer resulted in more efficient use of fer-
tilizer for the amount of labor required.
Significance to the Industry
Our data indicate that 1,994 pounds of fertilizer are
broadcast per acre each year on 1-gallon containers, 90
pounds on 2-gallon containers and 743 pounds on
3-gallon containers. For liquid fertilizer, 2,146 pounds
are applied per acre each year to 1-gallon containers,
449 pounds to 2-gallon containers and 1,839 pounds to
3-gallon containers. Increasing the number of con-
tainers per acre to 35,000 1-gallon, 25,000 2-gallon,
and 13,000 3-gallon containers (Extension Circular
589) would decrease waste fertilizer by approximately
31%, 18%, and 25%, respectively, when using broadcast
or overhead liquid fertilization methods.
The greatest opportunity to reduce waste of fertilizer
is through increased use of topdressing or incorpora-
tion. Liquid fertilization with a drip system would also
reduce waste; however, these data were not segregated
in the liquid fertilizer distribution summary. Topdress-
ing was used more frequently than incorporation, and
based on our data, 1,528 and 1,354 pounds of fertilizer
would be applied per acre each year by topdressing
1-gallon and 3-gallon containers, respectively.
Therefore, for an average nursery of 16.5 acres, and
assuming 50% of the production is 1-gallon plants and
50% is 3-gallon plants, 23,777 pounds of fertilizer
would be applied each year by the topdressing method.
Table 5. Commonly used fertilizer analyses by method.
Method Analysis (% by method)
INC 20-4-10 25
LIQ 20-20-20 19
TDR 12-6-8 8
BDR 16-4-8 18
No data 0.298
No data 0.291
No data 0.338
Appendix. Sample Forms Used for Data Collection
Fertilization Survey: Wholesale Container Nurseries
The Cooperative Extension Service is surveying a sample of the wholesale nurseries in Florida to determine the
amount of fertilizer and labor used in plant production. To be included in the survey, your nursery must have more
than 1 acre of 1-gallon or larger size container shrubs. The information you furnish is confidential but industry
averages will be available to the public. Please answer some questions about your container nursery business.
1. Do you broadcast dry fertilizer? If yes, please answer with information relative to the container sizes that you use.
Container size Application rate Times applied Brand Analysis Containers Hours or
(1- to 7-gallon) (lb per acre) per year per acre minutes of
to 1 acre
10 lb fertilizer/acre
4 lb nitrogen/acre
2. Do you topdress dry fertilizer? If yes, answer with information by container size (tsp, teaspoon; tbs, tablespoon).
Container size Application rate Times Brand Analysis Containers
(1- to 7-gallon) (tsp, tbs, or applied fertilized
fertilizer weight per year per hr
3. Do you incorporate fertilizer into container media and/or buy container media incorporated with fertilizer? If
yes, please answer with information by container size. (Include superphosphate but do not include lime and
Container size Application rate Brand Analysis Incorporated Hours or minutes
(1- to 7-gallon) (lb per cubic yard) at nursery to incorporate
(circle answer) fertilizer in 1 cubic
yard of media
4. Do you apply fertilizer in the irrigation water? If yes, please answer with information by container size.
Container size Application rate, Times Brand Analysis Containers Inches (or Hours or Drip or
(1- to 7-gallon) concentration or applied per acre gallons per minutes of trickle
gallons of concen- per year container) labor per irriga-
trated fertilizer irrigation fertilizer tion
used per acre in water application used
one application applied per to 1 acre (circle
10 lb fertilizer
per acre 200 PRI 10-10-10 34,000
5 gal concentrated
fertilizer per acre 50 ZSZ 6-5-2 800
0.5 in 10 min yes
1 gal 0.5 hr no
5. Please answer these questions about other aspects of your nursery business.
How many acres do you have in container-grown woody ornamental shrubs less than 8-gallon size? acres
Percentage of acreage in 1-gallon shrubs %
Percentage of acreage in 2-gallon shrubs %
Percentage of acreage in 3-gallon shrubs %
Percentage of acreage in 4-gallon shrubs %
Percentage of acreage in 5-gallon shrubs %
Percentage of acreage in 6-gallon shrubs %
Percentage of acreage in 7-gallon shrubs %
How important are fertilizer costs to your nursery business? very important important
not important to my nursery business.
Do you monitor the soluble salts level of the container medium? yes no
Thank you for your cooperation. Industry averages for the survey data will be sent to you in the future. Return
completed forms to: T. H. Yeager, Extension Ornamental Horticulturist, 2517 Fifield Hall, Gainesville, FL 32611.
The authors gratefully acknowledge nursery
operators and county extension faculty who partici-
pated in data collection, Justine Wetherington for
programming assistance and Robin Reddick for
Tradenames and companies are mentioned with the
understanding that no discrimination is intended or
endorsement implied by the authors or the University
This publication was produced at a cost of $1340.62, or 18 cents per copy, to guide commercial nursery operators in efficient
fertilization techniques. 11-7.5M-86.
COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLORIDA, INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES, K.R. Tefertiller,
director, in cooperation with the United States Department of Agriculture, publishes this information to further the purpose of the May 8 and
June 30,1914 Acts of Congress; and is authorized to provide research, educational information and other services only to individuals and institu-
tions that function without regard to race, color, sex or national origin. Single copies of Extension publications (excluding 4-H and Youth publica-
tions) are available free to Florida residents from County Extension Offices. Information on bulk rates or copies for out-of-state purchasers is ........ "
available from C.M. Hinton, Publications Distribution Center, IFAS Building 664, University of Florida, Gainesville, Florida 32611. Before publicizing this publication,
editors should contact this address to determine availability.