CITRUS NURSERY PRACTICES
By JACK T. McCOWN
Operating a citrus nursery poses many problems for the
Florida grower. Although there are many possible deviations,
adapting the suggestions in this circular to local conditions
should result in a successful nursery operation.
Before planting a citrus nursery, check with the Florida State
Plant Board about special regulations governing site selection
and other Plant Board requirements. The location of a citrus
nursery is regulated to decrease the chances of infecting nursery
trees with burrowing nematodes. In addition, special require-
ments are associated with the Citrus Budwood Registration Pro-
gram in an effort to eliminate the viruses psorosis, xyloporosis
and exocortis from citrus trees.
The seedbed should be located on well-drained virgin soil
capable of producing good growth of the seedlings. It should
be convenient to the producer, as frequent observation is im-
portant in determining the time when various seedbed practices
are to be carried out.
The soil fertility should be average. However, a degree of
soil fertility may be sacrificed for the sake of a location pro-
viding better cold protection and drainage. Irrigation should
be available, preferably the portable type. The rows should
be spaced to facilitate cultivation to keep the seedbed free of
weeds. Soil fumigation of the seedbed may help reduce the
The source of seed for planting is one of the most important
factors in developing healthy and disease-free citrus trees. Re-
cent research indicates that certain virus diseases may be trans-
mitted by the seed. Thus, the grower must select his rootstock
seed source from trees expressing the most desired horticultural
characteristics and use only seed known to be free of citrus
diseases. It is suggested that seeds be taken from trees which
are inspected frequently by the State Plant Board. Also, secure
seeds from fruit grown on seedling rough lemon and sour orange
trees which are located outside of commercial groves. At such
locations less seed-transmissible diseases appear to be present.
The best time for planting a citrus seedbed varies to some
extent with the location within the state. In the lower regions
of the citrus belt seed may be extracted and planted any time
during or after November, or at a time the desired fruit reaches
maturity. A seedbed in the northern region of the citrus belt
should be planted during late February or March. The daytime
soil temperature should reach about 700F. in order to obtain
good seed germination. The planting of a seedbed should not be
delayed until the time the soil temperature may reach 1000F.
during the day. If this occurs, the young seedling will be burned
when it emerges from the ground. Once the seedling attains a
height of one inch or more, or develops approximately three
leaves, it can withstand this heat without a high rate of fatality.
The seedbed may be planted by one of two methods. Prehaps
the most popular method is the open trench. A furrow is opened
approximately 11/ inches deep and the seed is planted rather
thickly in the bottom of the furrow. Often segments of the
fruit are placed along the bottom of the furrow.
Another method of planting, which usually results in better
seedlings, is known as the individual seed method. Individual
seeds are planted approximately one inch apart to a depth of 1/2
to 1 inch. It appears that less bench rooting (curving of the
tap root within 4 inches of the soil level) will occur when the
individual seed method is used. Rows of a seedbed may be 6
Fig. 1.-Typical citrus seedbed.
inches apart or wider, depending upon the method of cultivation
to be used.
Citrus seeds will require 4 to 6 weeks to germinate when
they are planted dry. Germination of dry seed may be hastened
by soaking in water for approximately 2 hours prior to planting.
However, soaking the seed usually makes planting somewhat
more difficult, due to the sticky substance on the seed coat.
The best seed germination may be expected when seeds are
planted immediately upon removal from the mature fruit. How-
ever, in order to plant certain species of citrus at a specifically
desired time, seed storage is often necessary. The seeds may
be extracted with a mechanical reamer, or by cutting through
the center of the fruit approximately one-half the distance from
the rind to the center, and carefully twisting the fruit apart in
order not to injure the seed.
When seeds are to be stored, freshly extracted seeds should
be washed with clear water and shade dried for a few days. Do
not dry seed on concrete, as concrete will hold moisture for a
long time, often causing a disease problem. One method is to
place seed on wood floors, or on a material such as vermiculite,
to keep the seed from sticking. Another method is to dry seeds
on canvas or wire screen in the shade.
If seeds are to be planted within 4 to 8 weeks, they may be
stored at normal home refrigeration temperature. Place seeds
in a small package, either in air-tight refrigerator bags or reg-
ular manila paper bags. If it is necessary to store seed for sev-
eral months, they should be treated. Use 1 ounce of 8-hydroxy-
quinoline sulfate to 1 gallon of water. The seeds should soak in
this solution 1 to 2 minutes. Then air dry them in the shade for
several hours and store in refrigerator as described above.
When the seedlings are 1 to 11/2 inches high, the first appli-
cation of a mixed fertilizer (4-7-5 or approximate equivalent
analysis) should be made to the seedbed. Use approximately
200 to 500 pounds of fertilizer per acre, depending upon natural
soil fertility. Fertilizer is best applied following an irrigation
or good rain after tops have thoroughly dried off. The ferti-
lizer should be brushed from the tops of the seedlings immedi-
ately following application to prevent burning of the leaves.
Fertilize at 3- or 4-week intervals, gradually increasing to a
maximum of 500 to 1,000 pounds per acre when the seedlings
are approximately 12 months old. A ratio of 1-1-1, with 15
to 20 percent of the nitrogen derived from organic sources, is
When seedlings first emerge from the ground they should
be sprayed with a fungicide to control damping-off. Seedlings
which are susceptible to scab and anthracnose infection should
receive a fungicide for the control of these diseases when they
are 6 to 8 weeks old. A tri-basic copper fungicide is often used
for the first application. Additional treatments, using either
copper, zineb or captain, should be applied monthly during most
of the growing season.
Fig. 2.-Seedlings ready for transplanting.
Watering is essential to produce healthy seedlings. The
moisture level should never be allowed to drop below 1/2 inch
in the soil during the first 6 to 8 weeks following planting. Dur-
ing the next 6 to 8 weeks the seedbed should receive approxi-
mately 1 inch of water every 3 to 5 days. To eliminate weed
competition, hand weed the seedbed prior to spreading the first
application of fertilizer. At this time the seedlings are approxi-
mately 1 to 11/2 inches high. In addition, hand hoeing will be
necessary every 3 to 5 weeks, depending on weed growth, to
keep the seedbed completely free of weeds.
After approximately 1 year's growth, the seedlings should
be 3/16 to 1/4 inch in diameter. At this time they are ready to
be lined out in nursery rows for budding. Dig seedlings from
seedbed with nursery spades. Do not pull seedlings from the
ground, as severe root injury will occur. At this time rogue
seedlings which have inferior root systems, "bulls" or "runts"
and other seedlings which are undesirable.
CARE OF THE SEEDLINGS
When seedlings are transplanted to nursery rows for bud-
ding, they are termed "liners". Upon being removed from the
Fig. 3.-Good and poor liners. Those on left have poor
root system, those on right good root system.
seedbed, the liners should be pruned to approximately 6-inch
tops and 6-inch root systems. Distance between seedlings and
rows will depend upon the growers' equipment for cultivation.
Plant liners approximately one foot apart in the row. The rows
may be three to five feet apart, depending upon the equipment
used. The nursery area should be thoroughly cleaned of all
vegetation and receive ample moisture prior to planting the
The liners may be planted with a dibble, being careful that
the soil is firmly packed around the roots. Do not plant seed-
lings too deep. They should be planted approximately the same
depth that they were growing in the seedbed. Irrigate the seed-
lings thoroughly after planting. If rainfall is not adequate,
apply approximately 1 or 2 inches of water each week during
the growing season.
Fertilize the seedlings within 2 to 4 weeks after lining out.
The first application should be about 50 pounds per 1,000 seed-
lings of a 4-7-5 or approximate equivalent analysis. The seed-
lings should be fertilized each 3 to 4 weeks. When seedlings are
Fig. 4.-Liners pruned, ready for transplanting.
approximately 3 months old, they may receive 75 to 100 pounds
of fertilizer per 1,000 trees.
Cultivation should accompany fertilizer application to elim-
inate weed competition and stimulate growth.
If liners are of varieties susceptible to anthracnose or scab
disease, follow a spray program similar to that suggested for
BUDDING THE NURSERY
The first step in preparation for budding a citrus nursery is
selecting the budwood. This is perhaps one of the most impor-
tant steps in developing a superior nursery tree. When pos-
sible, select budwood under the supervision of a State Plant
Board representative. Select the budwood that is certified free
of as many virus and other citrus diseases as possible. Partici-
pate to the fullest extent in the Budwood Registration Program,
sponsored by the State Plant Board.*
Budwood should be selected from trees known to be free of
bud-transmitted diseases and/or any other bud propagated dis-
orders. Budwood should be taken from trees true to type and
For information concerning the Budwood Registration Program con-
tact Budwood Registration Program, State Plant Board, Winter Haven,
Fig. 5.-Liners ready for budding.
tLA I AI
Fig. 6.-Good quality
Fig. 7.-Step 1-
the bottom of the
known to possess the ability to pro-
duce large quantities of high quality
fruit. Budsticks may be taken from
mature wood of the previous flush
of growth or from less mature and
more angular wood, which is now pop-
ular and has been used with good
results. It is best that budwood be
i dormant, yet possessing well-devel-
oped buds. Each budstick should be
clearly marked as to variety and tree
from which it was taken.
Best results will be obtained when
budwood is used fresh. However, if
storage of budwood is desired so that
the budding operation may be con-
ducted at a later date, it is suggested
that sticks be tied together in small
bundles, packed into clean, damp,
coarse sawdust and stored in a cool
dry place. Do not attempt to store
budwood longer than 3 to 4 months
under these conditions.
Citrus can be budded whenever
the bark will "slip" or
separate readily from the
wood. This condition ex-
ists during parts of
spring, summer and fall.
Most nurserymen bud
Streets during each of
these periods. Budding
should be done when the
stock is large enough to
facilitate budding a n d
One method of bud-
ding citrus is to insert a
shield bud into an in-
verted "T" slot cut into
the bark of the stock.
icrss cut at The trunk of a seedling,
which is 3/8 to /% inches in caliper, should be pruned clean of
thorns and limbs ahead of the budder to save time. Use a
sharp budding knife. Make a downward cut about 11/2 inches
in length. This is a vertical cut through the bark, but only
far enough into the
wood to be certain that
the bark has been com-
pletely cut. Now make
a cross cut (Fig. 7),
at the bottom of the
vertical cut, thus form-
ing the inverted "T". In
making this cut, the back
of the knife blade is
turned slightly do w n-
ward, so that the cut is
a little upward as well as
across the stock. At the
finish of the cross cut,
the knife blade is turned
slightly upward and giv-
en a slight twist to open
the bark at the junction
of the horizontal and
The bud is now cut Fig. 8.-Step 2-cutting the bud.
from a budstick held Cut is made toward the budder.
with the terminal end
away from the budder
(Fig. 8). The cut is to-
ward the budder and is
made parallel with the
axis of the budwood,
using a slight rotating
motion. The knife is
held with the blade al-
most parallel to the axis
of the budwood and the
thumb of the knife hand
is used to steady the
budwood while making
the cut. This will give Fig. 9.-Step 3-inserting the bud
a shield shaped piece of into the stock.
bark and wood about 3/4
to 1 inch long with a flat,
smooth cut surface. The
bud should not be
scooped out, as this
causes too much wood to
be taken with the bud.
Handle the bud between
the thumb and the knife
blade. It is now inserted
in the stock (Figures 9
Another method of
budding which has be-
come popular with many
budders is known as the
"hanging bud". In this
Fig. 10.-Bud inserted, ready for wrapping. method the budder cuts
a section of the bark
from the trunk about the
size of the bud which is
to be used. A "lip" is
made at the upper end of
the cut in order to hold
the bud in place.
The bud is cut in the
same manner as de-
scribed for the inverted
"T" method. In addi-
tion, the top of the bud
should be steeply tapered
by cutting off the front
surface. The tapered
cut forms a surface
which can be easily in-
serted under the "lip"
Fig. 11.-The hanging bud is inserted that has been cut on the
under a "lip," shown at the top of the stock (Figs. 11 and 12).
The most popular
means of wrapping a bud is with 4 mil. polyethylene plastic
strips 1/2 to 5/8 inches wide, 8 to 12 inches long, depending upon
the size of the stock. The wrap is started below the bud and
pulled firmly, but not too tightly, around the tree up to above
the top of the vertical cut (Fig. 13). There the end is placed
beneath the last circular wind of the wrap and pulled tightly
in place (Fig. 14).
When the budding is done in the spring, the wraps should
be removed between
14 and 18 days.
Wraps should not be
left on for more than
21 days. After the
wrapping is removed,
cut the seedling top
off smoothly j ust
above the bud, thus
allowing the bud to
m a k e unrestricted
growth. When the
seedling is very large,
sometimes the top is
lopped prior to being
completely cut off.
In lopping, the seed-
ling is cut approxi-
mately 3/1 the dis-
tance through the Fig. 12.-A "hanging" bud ready for wrapping.
trunk of the seedling
just above the bud
and the top is pushed
over and laid on the
ground. This allows
part of the seedling's
top to continue func-
tioning during the
time the bud is
Fall or dormant
budding lu s u a y Fig. 13.-Step 4-wrapping. .Start
is done during late below the bud, pull firmly'.
October and early
November. The wraps should remain on the bud until the trees
are ready for banking-around November 15. At that time the
bud is unwrapped and the seedling is banked well above the bud.
The bank is usually removed in February or early March, and
then the top of the seedling is cut off smoothly above the bud,
allowing the bud to grow.
When growth is
2 to 4 inches high,
place a stake beside
the bud for protec-
tion a nd support.
When the bud is 4
to 6 inches high, tie
it to the stake to help
prevent it from be-
ing broken off. The
bud should be tied at
regular intervals un-
til it reaches the top
of the stake, or is ap-
proximately 18 to 20
inches high. At this
point it should be
Fig. 14.-Step 5-wrap completed,
bud firmly in place. topped in order to
S*: During the
growth of the bud,
(using extreme care
not to injure the bud)
in order to eliminate
When rains are not
sufficient, 1 to 2 inch-
es of irrigation water
should be applied
each 7 to 10 days
during the summer
Do not fertilize
from several weeks
prior to budding un-
Fig. 15.-Step 6-young bud emerges, til after the bud has
top of seedling removed.
sprouted. When the
bud is 3 to 5 inches in length, apply 50 pounds of a 6-6-6-4-.5-.5
(N-P-K-MgO-MnO-CuO) fertilizer to each 100 trees. By the
time the bud reaches the top of the stake, fertilizer may be ap-
plied at the rate of 100 pounds per 1,000 trees every 4 to 6 weeks.
This should continue through the summer, with the last appli-
cation about September 15. Some nurserymen continue fertili-
zation until mid-October. However, this may not be a good
practice, since trees may be more susceptible to cold damage dur-
ing the winter. Spring fertilization should not begin before
February. From time to time during the growth of the nursery
tree nutritional sprays containing copper, manganese and zinc
are beneficial. Continually watch young nursery trees to de-
termine the necessity for applying insecticides and fungicides.
Insects and diseases must be kept at a minimum during the
growth of the young nursery trees to obtain healthy and vig-
Continued observation is necessary to time correctly spray-
ing, fertilization, irrigation and other cultural practices. With
proper care the nursery tree will be large enough for transplant-
ing into a grove within 10 to 18 months after budding. The
time interval between budding and transplanting will depend
largely on the desired caliper of the tree.
The superior nursery tree is a result of the nurseryman's
conscientious effort to carry out the best nursery practices.
The author wishes to acknowledge the assistance of Mr. John Kauff-
man, Jr., Grand Island Nurseries; Mr. W. F. Ward and Mr. Franklin Ward,
Ward's Nursery, in preparing this publication.
Reference: Florida Agricultural Extension Bulletin 139, Citrus Propaga-
tion, by Dr. A. F. Camp.
COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS
(Acts of May 8 and June 30, 1914)
Agricultural Extension Service, University of Florida,
Florida State University and United States Department of Agriculture. Cooperating
M. O. Watkins, Director
Your Boys Might Like to Enroll in a
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: County Citrus Medals
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