FRED P. LAWR
University of F
LL EXTENSION SERVICE
lorida, Gainesville, Florida
SOIL PREPARATION ..... ............. ... ... 3
SPACING .................... .... 3..
Staking or Marking the Rows ... ....... ........... 5
Placing Pollinator Trees ............. ... ...... 5
SELECTING TREES TO PLANT .. ........... ........ 5
RECEIVING THE TREES ............ ........... .................................... 7
PLANTING ...... ......... .. ....... ...... ..... ..................... 10
W A TERIN G ......... .. .... .............. ................... ............... 12
FERTILIZING ......................... ................ ................ ................ 12
CULTIVATION AND COVER CROPPING .......... ... ... .............................. ... 15
H erbicides ............. ... .. .. .......... .. .. ...................... 16
B AN K ING -............................... ........ . ..... ... ..... . .......... ....... 16
INSECT, DISEASE, AND PEST CONTROL .............. .. ....................... 17
PLANTING ON POORLY-DRAINED SOILS ............ ...... ................ 18
Site Selection ......... .............. ........................... 18
W ater Management ................ .... 19
Horticultural Practices ........ .... 20
Planting and Care of Young Citrus
FRED P. LAWRENCE
Citriculturist, Florida Agricultural Extension Service
Land on which young citrus trees are to be planted should be
cleared and the soil prepared well in advance of planting. Plant-
ing rough, uneven land which is full of roots and stumps will lead
to difficulties in cultivation. This can also result in needless loss
of young trees from such additional difficulties as mushroom
On well-drained soils it is the common practice to clear and
plant the land during the same year. After all native growth has
been removed and burned, the soil is customarily double-cut with
a bush and bog harrow. A heavy section of railroad-rail or simi-
lar drag should be attached behind the harrow to level the land.
Following this, all exposed roots should be piled and burned and
the land worked with a grove-type disk-harrow, followed by a
heavy drag. After a second piling and burning of roots, if the
land is still uneven, a second and possibly a third disking with a
grove-type disk and drag is recommended. The remaining roots
should be piled and burned.
The most popular planting patterns in Florida have been the
square and rectangle, and the most common tree spacings were
25'x 25' for oranges, tangerines, and tangelos; and 25' x 30' or
30' x 30' for grapefruit. With increased cost of land and produc-
tion, spacing practices are rapidly changing. Most growers now
prefer to plant more trees on each acre to increase per acre pro-
duction during the 5 to 25 year period, and later to hedge or
prune the trees to a desired height, size, and shape, or to thin the
stand by tree removal.
In his citrus record studies, Savage' found that trees spaced
to give a total of 80 to 99 trees per acre produced maximum yields
and maximum net returns during the first 24 years after planting.
From 25 to 40 years, spacings that gave approximately 80 trees
per acre were most profitable; above 40 years, spacings that
placed fewer than 60 trees per acre showed best results.
'Agricultural Economics Series 59-3 by Zach Savage, Agricultural Econ-
omist. University of Florida.
TABLE 1.-SETTING DISTANCES AND APPROXIMATE NUMBER
OF TREES PER ACRE.*
36x42 29 33x34 39 25x40 44
35x40 31 30x36 40 30x32 45
a) a) a
34x38 34 30x35 41 30x31 47
34x36 36 32x32 43 30x30 48
50 to 59 880 to 733 25x35 50 20x40 54 28x28 56
27x32 50 27x30 54 23x33 57
28x30 52 25x32 54 25x30 58
^ Ea ri
29x29 52 23x35 54 26x29 58
f-l CU p0 0) and s J
2240x40 27 35x35 36 30x33 44
60 to 69 732 to 627 27x27 60 23x30 63 22x30 66
3 6x42 29 33x34 39 25x40 44
35x4 0 31 30x36 40 30x32 45
34x3 8 34 30x35 41 30x31 47
___26x27 62 25x27 65 30x30 48
50 to 59 62880 to 733 25x35 50 20x40 54 28x28 56
27x32 50 27x30 54 23x33 57
228x30 52 25x32 54 25x30 58
29x29 52 23x35 54 26x29 58
22x3 7354 26x3026 76 23x24x31 59
60 to 69 54732 to 627 27x27 60 23x30 63 22x30 66
1825x29 60 20x34 64 25x2 6 67
26x2 8 60 26x26 64 18x36 67
20x35 62 24x28 65 23x2 8 68
1926x28 82 25x27x3 85 19x26 88
70 to 99 626 to 548 25x25 70 22x27 91 19x24 96
21x23 90 17x28 92 15x30 97
24x26 70 23x26 73 24x24 76
22x28 71 17x34 75 20x28 78
21x29 72 19x30 76 22x25 79
20x24 91 22x23 9576 2x2 79
100 and over 437 and less i 19x23 100 16x26 105 18x20 121
21x26 80 22x24 83 198x28 86
18x30 81 20x26 84 21x24 86
20x27 81 15x34 85 22x23 86
| 23x23 82 16x32 85 20x25 87
19x27 101 18x22 110 8x19x26 12788
90 to 99 I486 to 438 18x27 90 16x30 91 19x24 96
21x23 90 17x28 92 15x30 97
22x22 90 21x22 94 18x25 97
15x32 91 17x27 95 20x22 99
I ____________20x24 91 20x23 95 21x21 99
100 and over 437 and less !| 19x23 100 16x26 105 18x20 121
15x29 100 15x27 108 19x19 121
18x24 101 20x20 109 16x22 124
16x27 101 18x22 110 18x19 127
17x25 102 14x28 111 17x20 128
14x30 104 15x25 116 13x26 129
* Courtesy of Zach Savage, Agricultural Economist, University of Florida.
With the development of new varieties, rootstocks, and cul-
tural practices, this will likely change, but with current prac-
tices, stocks, and scions, approximately 100 trees per acre seems
to be about right. See Table 1 for suggested spacings for spe-
cific numbers of trees per acre.
Staking or Marking the Rows
After the soil is prepared, the land is laid off and/or staked
for planting. In the past, a common practice was to use a sur-
veyor's transit and set a stake where each tree was to be plant-
ed. A more modern and less expensive procedure is to establish
a king-row or base row with the use of surveying instruments
and to use tractors with row markers to check-row the area to be
Possibly the most important consideration in laying out an
area for planting is to allow sufficient space for turning grove
machinery at the ends of the rows. It is customary to offset 15
feet from all boundary lines. If each grower adheres to this pro-
cedure, the resulting 30-foot space between trees in adjoining
groves will permit minimum room for turning. It would be more
satisfactory and afford greater saving of time if this distance
were increased to a minimum of 20 feet from each boundary line.
Placing Pollinator Trees
Recent research has proven that Orlando and Minneola tan-
gelos, Clementine Mandarin, and some other hybrid varieties are
only weakly parthenocarpic; when planted in solid blocks or in
isolated plantings, yields and the size of individual fruits are
materially reduced. To overcome this, it may be desirable to
interplant these varieties with other varieties that will act as
pollinators. The spacing of these pollinator trees should receive
considerable thought prior to staking or "laying off" the area to
be planted. Suggestions for the correct placement of these pol-
linator trees are presented in the diagrams on page 6.
SELECTING TREES TO PLANT
Don't buy bargain trees. Use the best trees available. Nor-
mally these are registered trees. The purpose of the State Citrus
Budwood Registration Program is to assist nurserymen and
growers (who cooperate in the program) to grow citrus nursery
trees that are believed to be free of viruses and other recogniz-
able bud-transmissible diseases. Currently it is possible to pur-
chase trees that are registered (by the Division of Plant Indus-
try) to be free of one, two and possibly three known viruses. In
addition to buying registered trees, look for:
1. A healthy, vigorous tree.
2. One that will caliper 5/8 to 11/4 inches, 1 inch above the
3. Smooth textured bark, free of scars.
4. A well-formed root system with ample lateral and feeder
roots and a straight tap root.
SUGGESTED POLLINATOR PLANTING PLANS FOR ORLANDO TANGELOS
USING TEMPLE AS A POLLINATOR*
The basic principle is to have each Orlando tree no farther than two rows
from a Temple.
0 P 0 0 P 0
O 0 0 0 0 0 Planting Plan A.-Start with the second tree
0 0 0 0 0 0 in the second row. Then every third tree in every
third row is a pollinator, or each center tree in a
O P O O P 0 3 x 3 square of trees is a pollinator. This plan
requires fewer pollinators than other suggested
0 0 0 0 0 0 plans but harvesting and spraying are made more
0 0 0 0 0 0 difficult by the scattered trees.
O P 0 0 P O
0 0 0 0 0 0
O O P O 0 O O P 0 O
Planting Plan B.-Starting with
O O P O O O O P O O the third row, every fifth row is a
pollinator row. This facilitates
0 0 P 0 0 0 0 P 0 0 spraying and harvesting but re-
0 0 P 0 0 0 0 P 0 O quires more pollinators than Plan A.
O O P O O O O P 0 O
O P P O O O P P 0 O Planting Plan C.-Some-
times growers prefer to plant
O 0 P P O O 0 0 P P O O a "picking row" of pollina-
tors; that is, starting with
O O P P O O O O P P O 0 the third row, as in Plan B,
two pollinator rows are used.
O O P P O O O O P P O O Spraying and harvesting are
O O P P O O 0 0 P P O O facilitated even more than in
*Courtesy of Dr. A. H. Krezdorn, Head, Fruit Crops Department, University of Florida.
1. Crooked, mal-formed, deficient, insect infested or diseased
2. Trees with mal-formed roots, especially one with a de-
formed tap root.
3. Budded trees that have remained in a nursery longer than
two years after budding, especially if they are small and
^ "'- i .-.-
,t .. ''- ^.:. .
Figure 1.-A good young citrus tree: left, ready for planting, with
top and root system trimmed; right, set and watered in.
Inspect the trees in the nursery prior to purchase. At deliv-
ery time keep in touch with the nurseryman. Tell him the height
of head, length of limbs and roots desired, and-most important
-tell him, exactly to the hour, when and where the trees are to
be delivered. Leave no doubt as to who is to deliver the trees,
how they are to be delivered, and the variety to be delivered on
each day, if there is to be more than one variety or delivery.
RECEIVING THE TREES
Far too few growers pay sufficient attention to this very
important step in the process of planting young citrus trees. Dig-
going, trimming, transporting, and planting is a great shock to the
tree and should be accomplished with maximum care and in the
shortest possible time. If the trees are to be hauled any distance,
provisions should be made to move them in an enclosed truck
body or similar carrier which will protect them from unnecessary
drying and fraying by sun and wind. The trees should be kept
moist to protect the root system. Once the roots dry out, they
cease to function. It is best to pack the roots in moist sphag-
num, sawdust or other similar moisture-holding material and to
transport the trees in the early morning when it is usually cool
Have a cool, shady place to unload the trees and a planting
crew standing by with sufficient tools, water, etc. to do the job
rapidly and efficiently. The cardinal point in receiving young
trees at the planting site is to be ready.
One of the common mistakes in receiving trees is that of not
having a proper place to unload and hold them during the plant-
ing operation. Too many trees are left on the truck, under a
tarpaulin with the truck standing in the direct sun. If there is
no shed, building, or shade under which the trees can be placed,
then they should be heeled into the soil. Wet the soil thoroughly.
Erect a frame at least three feet off the ground and spread a
tarpaulin over the frame for shade. Leave the sides open for air
circulation. Do not pile the trees one on the other in such a man-
ner that air pockets will form around the roots. It is better to
put in a row of trees, cover the roots lightly, wet the soil, and
then place a second row on top of this. Stack heeled-in trees not
more than three deep. (See Figure 2.)
Some organizations and large commercial nurseries have
trucks especially built to serve as supply units during the plant-
ing operation. These are high solid-sided (usually plywood)
trucks with a canvas top. On each side of the rear bed is a well
into which is fitted a 50-gallon drum of water. These act as
holding containers for the trees that are being planted. The truck
bed is used to store trees for the remainder of the day. The roots
of these are covered with sawdust or sphagnum that is wet down
frequently. (See Figure 3.)
For daily storage, trees can be placed in a lake or stream.
This is not the best practice, and trees should not be left in this
manner for more than a few hours.
Finally, it is a good policy to receive no more trees than the
crew can plant and water the same day.
ered with canvas.
Figure 3.-Water drums on this specially built truck keep root systems
wet while trees are transported to the grove and while they are held for
Citrus trees can be planted any month of the year with reason-
able success. They are planted to best advantage, however, dur-
ing the time they are most dormant. Probably the best period is
during the late winter and early spring. Some growers follow
the practice of planting during the first two weeks of December,
but in this case it will be necessary to bank the trees for cold pro-
< '< .. -
Figure 4.-A well-organized planting crew. One worker removes trees
from the truck and trims the roots. The next man places the tree in a water
bucket, and the third man sets the tree in the ground.
In commercial plantings made with hand tools, it is suggested
that the crew be formed around the water wagon on which a con-
tainer, preferably under cover, is provided to haul the trees. Fre-
quently this is a drum or vat containing water. One trained man,
with hand clippers, should take the trees from the water wagon
and trim away all broken or undesirable limbs and roots. A sec-
ond man, commonly called a water boy, should take the tree,
place it in a three- to five-gallon bucket of water and carry it over
to the setter.
Most setters, planting in sandy soil, prefer to use an eye-hoe
that has had the handle shortened to about three feet. The end
of the hoe handle is usually pointed. The setter should drag the
soil away from the stake, or otherwise marked position for the
new tree, forming a basin only sufficiently deep to accommodate
the lateral roots. With the sharpened end of the hoe handle he
should make a hole for the tap root. The young tree is then set
in place. If the basin is too deep the tree must be lifted and suffi-
cient soil pushed back into the basin to enable the tree-when
planted-to stand at exactly the same depth that it grew in the
nursery. After the tree has been set at the correct depth, place
the hoe handle into the soil beside the tap root, packing the soil
around the tap root. The basin needs to be partially filled with
soil and water so the setter can work the wet soil around the tree
roots with his hands. Then the hole is filled.
A second man with a hoe should follow the setter and build a
large soil ring around the freshly set tree. The basin thus formed
is filled immediately with 5 to 10 gallons of water. As the water
settles into the soil, a clean-up man tramples the soil firmly
around the newly set tree and reinforces the water ring. For
best results, the tree should be watered again on the day follow-
ing planting and thereafter at two-to five-day intervals, depend-
ing on weather conditions, until the tree becomes established.
Figure 5.-Mechanical equipment digs a hole and forms a water basin
at the same time. Water tanks on the same rig enable the planting crew
to water trees in as they are planted. (Photo courtesy Florida Grower and
Many commercial plantings are now being made with the use
of power augers and mechanical cuppers that dig the hole for the
young tree and erect a water ring at the same time. This is usu-
ally much faster but the tree setter requires constant supervision
to avoid his setting the young trees too deep.
Many growers follow the practice of hauling young trees
stacked in a pile on the water wagon with one or more men drop-
ping the trees ahead of the planter. This is a poor practice and
should be discouraged. It is also a poor practice to place a young
tree in a pre-dug hole, partially cover it and let it stand from a
few minutes to 24 hours before it is watered.
For the sake of emphasis-never let the roots dry! Keep the
trees in the shade as much as possible. Don't drop young trees
on the hot sand ahead of the planter.
Trees planted prior to the passing of hazardous cold weather
should be banked immediately after the first watering (at plant-
ing) and left so until the arrival of warm weather. Form a wa-
tering basin around the bank and water the trees as needed.
If young trees are planted properly, they can stand two to
five days (depending on weather conditions) before being re-
watered. However, under normal conditions the safest proce-
dure is to apply five to ten gallons of water at planting and repeat
it on the second or third day. Then re-water every two to five
days until the trees become well established. It is a poor prac-
tice to let young trees go into a wilt. Rainfall of less than 2 in-
ches should be disregarded. Dormant plantings may require only
one or two waterings until early spring when banks are removed.
The practice of mixing fertilizer in the soil or water at plant-
ing usually is more detrimental than beneficial. It is almost im-
possible to add fertilizer at planting without at least some root
injury. If a healthy tree is planted, it has sufficient stored food
to sustain itself adequately until visible signs of growth appear.
This usually occurs in three to six weeks, depending on time of
planting and weather conditions.
Trees planted in the winter begin to grow with the passing of
cold weather. At this time they should be unbanked and ferti-
lized. Spring and summer planted trees usually stand three to
six weeks before showing signs of growth. Generally it is well to
wait for signs of growth before beginning any program of fertili-
zation. A fertilization program such as is outlined in Florida Ex-
periment Station Bulletin 536A is recommended. That portion
of this bulletin which seems most appropriate here reads:
"Uncultivated soils are generally very infertile with respect
to all the essential elements except phosphorus in some cases.
Therefore, young trees in previously unfertilized soils should re-
ceive regular applications of nearly all essential elements. Trees
in replanted areas or occasional replants in present groves should
receive the fertilizer mixtures recommended for bearing trees,
but in reduced amounts sufficient to give about the same nitrogen
and potassium levels as recommended for trees planted on new
land (Table 2).
TABLE 2.-SUGGESTED FERTILIZATION GUIDE FOR YOUNG TREES
UP TO 10 YEARS OF AGE.
Year in Grove
Pounds Per Application Per Tree**
Range I Average
0.25 0.40 0.33
0.75 1.25 1.0
1.5 -2.5 2.0
3.5 -4.5 4.0
4.0 5.0 4.5
4.5 5.5 5.0
5.0 -6.0 5.5
5.5 -6.5 6.0
6.0 -7.0 6.5
6.5 7.5 7.0
For trees planted after February 1, the number of applications should be correspond-
**Use 8-2-8-3-0.5-0.25-0.1 mixture or equivalent. This is a relatively strong fertilizer for
young trees and care should be used to see that it is spread evenly over the entire rooting
area-and slightly beyond.
Other fertilizer formulas may be satisfactory." The most
desirable formula, however, should contain only adequate
amounts of all the elements essential to good tree growth and not
excessive amounts of any element. Nitrogen and potassium are,
by far, the most soluble nutrients and are rapidly leached from
the limited root zone of newly planted trees. Consequently, they
are required in larger amounts than the less soluble nutrients
which tend to accumulate and remain available in the root zone.
"The following ratio of elements will satisfy the requirements
of young, non-bearing citrus trees under most conditions: N-l,
P20,-1/4, KO0-1, MgO-1/2, MnO-1/16, CuO-1/32, B20s-1/100.
The elements in this ratio and order can be made into a fertilizer
mixture such as 8-2-8-4-0.5-0.25-0.1. Higher analysis mixtures
are generally more economical and may be used, but the difficul-
ty of obtaining uniform applications around the root zone is in-
creased. Extreme care should be taken to avoid root damage due
to excess salt concentrations in localized areas brought about by
"A suggested schedule of fertilization for a grove planted
during the dormant season is given in Table 2. The rate and
number of applications of fertilizer should be based primarily on
age and condition of the tree. Trees should be fertilized about
every six to seven weeks for the first year. The frequency of
application may be reduced in succeeding years.
"Rate of application the first year should be relatively low be-
cause of the limited root system of the tree, but should be in-
creased sharply the next few years. Spread fertilizer evenly over
the area in a 30-inch circle the first year; avoid putting fertilizer
against the trunk, in piles or bands.
"After the first year the fertilized area should be steadily en-
larged each application. A good rule to follow is to cover an area
twice the diameter of the tree canopy. For a tree with a 3-foot
canopy, apply the fertilizer uniformly over a circle 6 feet in diam-
eter. Fertilizer applications should be omitted between October
1 and February 15 for the first year or two to reduce the possibil-
ity of inducing untimely growth flushes in the winter."
In the northern limits of the citrus belt, fertilization should be
stopped in late August or early September.
"On acid soils an application of dolomite or high calcium lime-
stone should be made before or shortly after planting, at the rate
of 1 ton per acre. One application will usually give sufficient pH
control for the first five or six years, after which the pH should
be adjusted to 5.5 to 6.5 annually, as for mature trees.
"The emphasis the first five years should be on making tree
growth with the quality of the crop secondary. From about the
sixth to tenth years the trees will come into appreciable commer-
cial bearing but still will benefit from a complete fertilizer.
During this period, begin the shift to a program for bearing trees.
This would include changing from hand to machine applications
"When a mechanical spreader is first used, it should be driven
close to the trees, using a one-side spread so that only a swath of
10 to 12 feet down each side of the tree row is fertilized. After
one or two years of this, the fertilizer can be spread uniformly
over the whole ground area (except for the water furrows of bed-
ded groves). This will provide an over-all application of phos-
phorus for improved cover-crop growth and will fortify the soil
with manganese and copper. Use three applications per year at
the rates indicated in Table 2."
From the eleventh year on, follow the program for full bearing
trees given in the first part of Bulletin 536A.
"Usually it is advisable to supplement the fertilizer applica-
tions with nutritional sprays containing zinc. Make one applica-
tion each year using 3 pounds of zinc sulfate plus 1 pound of hy-
drated lime per 100 gallons or its equivalent in neutral zinc ma-
terial. On poorly-drained and/or calcareous soils, or wherever
symptoms of manganese and copper deficiencies appear, the nu-
tritional spray should also contain manganese and copper. These
may be supplied by adding 3 pounds of copper sulfate, 3 pounds
of manganese sulfate and 1.3 pounds of lime or equivalent
amounts of neutral materials to each 100 gallons of spray."
CULTIVATION AND COVER CROPPING
Summer cover crops are beneficial in Florida's citrus plant-
ings; however, winter cover crops have not generally been rec-
ommended because of insufficient and unreliable information on
their value and the extent to which they may (or may not) in-
crease the cold hazard. If young trees are set in late fall or win-
ter in soils that are supporting little or no plant growth, it may
be advisable to plant oats, rye, or lupine to help protect the young
trees from sand blast and the soil from wind erosion.
On newly planted soils, dolomite or agricultural lime should
be applied, as recommended under the section on fertilization,
prior to planting the cover crop. Five to six hundred pounds of an
8-8-8 fertilizer per acre for oats or rye or 300 to 400 pounds of
0-10-12 per acre for hairy indigo or other summer cover crop,
broadcast prior to seeding, will greatly improve the stand and
growth of the cover crop. It is customary to let the summer
cover crop grow from early spring to early fall. However, all
cover crop growth (including weeds) in an area four to six feet
in width or diameter around the young trees should always be
controlled to the extent that it will not compete with the young
tree for fertilizer and moisture. This may be done by strip-
cultivating on each side of the tree, using a small grove disk,
acme harrow, or other suitable tool. Mechanical hoes or hand
hoes must be used to keep the area immediately around the tree
free of all vegetative cover.
^________ ____ ** -H .tfrrj^^
r P~c' "U'. r7
Figure 6.-Oats as a cover crop in winter and early spring.
Recent research concerning the use of herbicides indicates
they may be used in young citrus groves to control cover crops
and weeds in the area immediately around the young tree. For
complete information on this subject refer to Extension Service
Banking should be started in sufficient time to have all trees
protected by the 15th of November. A good practice is to scrape
off the top soil and bank the young trees with sub-soil. Where
mechanical bankers are used this is impractical, however, and
since the presence of woody material in the bank may induce
termites, sift about 1/ cup of 5 percent chlordane dust around the
base of the tree prior to banking. A second .3 cup should be
sifted around the tree when the bank is about half constructed.
Some mechanical bankers apply insecticide. For maximum pro-
tection young trees should be banked well above the main scaffold
With the passing of cold weather, the banks should be re-
moved and the spring cultural program started.
S 4 ..
Figure 7.-Lupine as a cover crop in a grove of young trees.
Rows run north and south.
INSECT, DISEASE, AND PEST CONTROL
While young citrus trees do not normally require an extensive
and complicated spray program, it is imperative that they be in-
spected frequently for aphids, scales, mites, grasshoppers, mil-
lipedes, and orange dogs. The latter is frequently a severe pest
in late summer and early fall.
The foliage of most varieties of young citrus is usually rela-
tively free of fungi, however, certain varieties are especially sus-
ceptible to citrus scab and practically all varieties are susceptible
to greasy spot. If either appears as a general infestation or an
acute infestation on a few trees, control measures should be start-
Foot rot, collar rot, brown rot, and a few other parasitic-type
fungi may attack young tree trunks. These attacks are usual-
ly worse when young trees are standing in the bank and during
the warm summer rainy period. Frequent inspections should be
made during these periods in order that such attacks may be de-
tected and treated before they do serious harm to the trees.
2 Refer to the current Better Fruits Spray and Dust Schedule for the
latest recommended control.
Salamanders (pocket gophers) may be especially harmful to
young banked trees during winter months when their natural
food supply becomes limited. Gophers (land turtles) and arma-
dillos sometimes build their burrows under young trees. This
will usually damage or kill the tree.
PLANTING ON POORLY-DRAINED SOILS
The rapid expansion of the Florida citrus industry during re-
cent years has resulted in almost complete utilization of the well-
drained soils considered most suitable for citrus. Because of
this, future plantings will of necessity have to go onto soils that
have previously been considered to be marginal for citrus grow-
ing. These are, in the main, the poorly-drained soils which com-
pose the largest land area of peninsular Florida.
Planting of these soils to citrus is proceeding at a rapid pace
without the benefit of extensive research findings and grower ex-
perience. It is important that growers realize the risk involved
in using these soils. The problems facing the prospective develop-
er of these lands can be grouped into the three broad categories
of site selection, water management, and horticultural considera-
Temperature.-Temperature is a prime factor in site selec-
tion. Most poorly-drained soils are noted for their low tempera-
tures due to low elevation and poor air drainage. This is often
true even in locations south of the current citrus area. Within a
given area both colder and warmer locations can be found. Local
land elevation is possibly the most important factor affecting
temperature in any one location. An elevation difference of as
little as four or five feet above the surrounding area can mean a
temperature difference of two to five degrees on calm, clear, cold
Soil Types.-There are two broad categories of poorly-drained
soils: (1) shallow soils underlain with alkaline material and
(2) acid poorly-drained soils.
Many of the poorly-drained soils are strongly acid and defi-
cient in practically all plant mineral elements, including the trace
elements. This is especially true of soils having thick, light col-
ored sand layers. In acid poorly-drained soils, the color and thick-
ness of the surface soil, the depth to the organic stain, or pan, and
the color of the subsoil will influence the growth of citrus and con-
sequently the horticultural practices that must be followed. Most
of these acid poorly-drained soils contain a leached, white sand
layer over an organic pan; and in general, the whiter the sand,
and the thicker the leached layer above the pan, the poorer the
land for citrus. The principal soil types found in this category
are Scranton, Ona, Leon, Immokalee, and Pomello.
In the main, the soils which are underlain with alkaline ma-
terials are the more fertile and are usually better suited to citrus
production. This group is comprised of such recognized soil types
as Felda, Parkwood, Bradenton, Sunniland, and Adamsville.
Many prospective growers, in selecting these soils, make the
mistake of thinking in terms of drainage only; equally as impor-
tant is the provision for adequate irrigation due to the limited
root system of citrus growing on these soils.
Drainage.-Adequate provision for the removal of excess wa-
ter must be made. The mere fact that the land can be ditched,
diked, and pumped is not sufficient. Adjacent lands are likely to
be planted with the same thought in mind, and very quickly there
may be an excess of water with no place to flow. In large areas
of poorly-drained soils, not in drainage districts, this is frequently
overlooked. Free water in the root zone for a few days will do no
great damage, but flooding for a week will likely result in severe
Adequate drainage includes both surface and subsurface
drainage. Surface drainage is provided to remove excess surface
water rapidly during and after heavy rains. This is usually ac-
complished by ditches. Water which soaks into the soil and
raises the water table must be removed by subsurface drainage.
This can be done through the use of tile3 or open ditches. The
subsurface drainage system must keep the water table at least
three feet below the soil surface-except for a few hours at a
time. Both surface and subsurface drainage are necessary for
water control in most of the poorly-drained soils.
Irrigation.-On soils which require draining, irrigation is usu-
ally necessary because of the limited root penetration. The depth
of rooting and the physical properties of the soil determine the
amount of water that will be available to the plant during peri-
SA number of tile lines have been found clogged by a reddish brown ma-
terial. Research indicates this results from bacterial reduction of ferrous
iron in some soils. Local Extension Service or Soil Conservation Service
personnel should be consulted before tile systems are installed.
ods of drought. Adequate drainage in wet weather results in
less frequent need for irrigation during other periods.
In general, sprinkler irrigation systems are more suitable on
poorly-drained soils than subsurface or ditch systems.
Soil Erosion.-Most poorly-drained soils selected for citrus
will have an erosion problem unless reasonable care is exercised
in providing for surface drainage. Poorly-designed systems of
bedding and ditching are a constant source of erosion, puddling
and expensive "wash-outs".
The design and construction of an adequate water manage-
ment system requires a great deal of technical skill. In the long
run, the employment of professional engineers to design the sys-
tem will be the most economical practice.
The special management practices required for citrus on mar-
ginal soils increase production costs. In addition, citrus on
poorly-drained soils has been found to produce appreciably less
fruit than trees on deep, well-drained sands. Also, the life ex-
pectancy of the trees is shorter.
S, __. ".....-I -. .-,. "" o .
Nat-mi& J -
Figure 8.-Planting on poorly drained flatwoods soil. A tractor-drawn
pump supplies enough water from a nearby canal to "jet-set" two rows at
once. (Photo courtesy Minute Maid groves.)
Soil Preparation.-Usually it is necessary to dig the main
canal and rim ditches prior to clearing the land. To do so not
only insures better working conditions for the bulldozers during
the clearing operation but also lessens the chances of work stop-
page due to heavy rains.
Figure 9.-One of the planting crew works soil in around the roots of a
"jet-set" tree while the crew for the water supply unit move the rig on
down the row. (Photo courtesy Minute Maid groves.)
Many of the poorly-drained soils do not have sufficient growth
to warrant extensive bulldozing. Others require the use of Webb
plows or other special tools to uproot palmettos and other low
growing plants. These are raked, piled, and burned. After the
land has been cleared it may be cut with a bush and bog harrow
or plowed with a plow capable of turning furrow about 42 inches
deep. Dolomite or lime, if needed, should be applied at this time.
The deep plowing turns out, breaks up and thoroughly mixes the
hard pan (and lime if added) into the soil.
The next step is to decide on tree spacing and the bedding
system to be used. Single row, double row, or multiple row beds
may be used. The land is then laid off for the desired system of
bedding, and by the use of a patrol grader the land is leveled and
the beds constructed. Level beds are a must. Uneven beds are
a constant source of trouble. Usually it is advisable to employ
a drainage engineer to lay out the bedding system, direction of
rows, and the correct spacing of ditches or tile lines.
As soon as the beds have been constructed, the soil should
be limed (if not already applied) and planted to a quick growing
cover crop such as rye or oats to help stabilize the beds. The rows
are then laid off or staked and the young trees planted. The
planting technique is about the same as for well-drained soils ex-
cept that the planter uses a shovel rather than a hoe to make the
holes for the young trees. Planting also may be done by use of
tractors equipped with augers. Some are using water under pres-
sure to make holes for planting the trees.
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. 0. Watkins, Director