Bulletin 194 February, 1928
UNIVERSITY OF' FLORIDA
AGRICULTURAL EXPERIMENT STATION
HAROLD MOWRY AND A. F. CAMP
Fig. 112.-Blueberries packed and ready for shipment.
Bulletins will be sent free upon application to the
Agricultural Experiment Station
BOARD OF CONTROL
P. K. YONGE, Chairman, Pensacola E. L. WARTMANN, Citra
E. W. LANE, Jacksonville J. T. DIAMOND, Secretary, Talla-
A. H. BLANDING, Leesburg hassee.
W. B. DAVIS, Perry J. G. KELLUM, Auditor, Tallahassee
STATION EXECUTIVE STAFF
WILMON NEWELL, D. Sc.. Director ERNEST G. MOORE, M. S., Asst. Ed
JOHN M. SCOTT, B. S., Vice-Director IDA KEELING CRESAP, Librarian
S. T. FLEMING, A. B., Asst. to Di- RUBY NEWHALL, Secretary
rector K. H. GRAHAM, Business Manager
J. FRANCIS COOPER, B. S. A., Editor RACHEL MCQUARRIE, Accountant
MAIN STATION-DEPARTMENTS AND INVESTIGATORS
AGRONOMY BRUCE McKINLEY, B. S. A., Asst.
W. E. STOKES, M. S. Agronomist M. A. BROOKER, M. S. A., Asst.
W. A. LEUKEL, Ph. D., Asso. ECONOMICS, HOME
C. R. ENLOW, M. S. A., Asst.* OUIDA DAVIS ABBOTT, Ph. D., Chief
FRED H. HULL, M. S. A., Asst. L. W. GADDUM, Ph. D., Asst.
A. S. LAIRD, M. S. A., Asst. C. F. AHMANN, Ph. D., Asst.
ANIMAL INDUSTRY ENTOMOLOGY
JOHN M. SCOTT, B. S., Animal J. R. WATSON, A. M., Entomologist
Industrialist A. N. TISSOT, M. S., Asst.
F. X. BRENNEIS, B. S. A., Dairy H. E. BRATLEY, M. S. A., Asst.
CHEMISTRY A. F. CAMP, Ph. D., Asso. Hort.
R. W. RUPRECHT, Ph.D., Chemist M. R. ENSIGN, M. S., Asst.
R. M. BARNETTE, Ph. D., Asst. HAROLD MOWRY, Asst.
C. E. BELL, M. S., Asst. G. H. BLACKMON, M. S. A., Pecan
H. L. MARSHALL, M. S., Asst. Culturist
J. M. COLEMAN, B. S., Asst. PLANT PATHOLOGY
J. B. HESTER, B. S., Asst. O. F. BURGER, D.Sc., Plant Pathologist
COTTON INVESTIGATIONS G. F. WEBER, Ph. D., Asso.
W. A. CARVER, Ph. D., Asst. K. W. LOUCKS, B. S., Asst.
M. N. WALKER, Ph. D., Asst. ERDMAN WEST, B. S., Mycologist
E. F. GROSSMAN, M. A., Asst. VETERINARY MEDICINE
RAYMOND CROWN, B.S.A., Field Asst. A. L. SHEALY, D.V.M., Veterinarian
ECONOMICS, AGRICULTURAL D. A. SANDERS, D. V. M., Asst.
C. V. NOBLE, Ph. D., Ag. Economist E. F. THOMAS, D. V. M., Lab. Asst.
BRANCH STATION AND FIELD WORKERS
W. B. TISDALE, Ph. D., Plant Pathologist, in charge, Tobacco Experiment
Ross F. WADKINS, M. S., Lab. Asst. in Plant Pathology (Quincy)
JESSE REEVES, Foreman, Tobacco Experiment Station (Quincy)
J. H. JEFFERIES, Superintendent, Citrus Experiment Station .(Lake Alfred)
W. A. KUNTZ, A. M., Assistant Plant Pathologist (Lake Alfrbd)
R. L. MILLER, Assistant Entomologist (Lake Alfred)
W. L. THOMPSON, Assistant Entomologist (Lake Alfred)
GEO. E. TEDDER, Foreman, Everglades Experiment Station (Belle Glade)
R. V. ALLISON, Ph. D., Soils Specialist (Belle Glade)
J. H. HUNTER, M. S., Assistant Agronomist (Belle Glade)
J. L. SEAL, Ph. D., Assistant Plant Pathologist (Belle Glade)
H. E. HAMMAR, M. S., Field Assistant (Belle Glade)
L. 0. GRATZ, Ph. D., Associate Plant Pathologist (Hastings)
A. N. BROOKS, Ph. D., Associate Plant Pathologist (Plant City)
A. S. RHOADS, Ph. D., Associate Plant Pathologist (Cocoa)
STACY O. HAWKINS, Field Assistant in Plant Pathology (Homestead)
D. G. A. KELBERT, Field Assistant in Plant Pathology (Bradenton)
R. E. NOLEN, M. S. A., Field Assistant in Plant Pathology (Monticello)
FRED W. WALKER, Assistant Entomologist (Monticello)
E. D. BALL, Ph. D., Associate Entomologist (Sanford)
*In cooperation with U. S. Department of Agriculture.
BLUEBERRY CULTURE IN FLORIDA
HAROLD MOWRY AND A. F. CAMP
The commercial growing of blueberries in northwestern Flor-
ida had its inception in a planting made about 35 years ago
near Crestview, Okaloosa County, by the late M. A. Sapp. This
original planting, made up of plants found growing wild in that
vicinity and transplanted to the owner's farm, has continued to
bear satisfactory crops of fruit annually and is in good condition
at the present time.
For several years the fruit was sold on the local markets,
which could consume only a small quantity and which paid a
very low price, since sufficient wild fruit to supply the demand
could be had for the picking. During the seasons of 1920 and
1921 some trial shipments to Northern cities brought such satis-
factory returns, in spite of the crude containers in which they
were packed, that an enthusiastic interest was aroused and has
resulted in the planting of a considerable acreage in north-
western Florida and some additional acreage in neighboring
There being no nurseries from which the plants could be ob-
tained, the digging and selling of the wild plants became for a
time a lucrative business and in some instances was exploited to
the fullest extent. Usually no care was taken in the selection of
the plants, due partly to a lack of knowledge as to what might
constitute a desirable type but more frequently to the fact that
the plants were dug during the winter, when in a dormant con-
dition, so that nothing could be told as to the quality of the fruit.
In fact, a large number of the plantings made prior to 1924
have many plants (Polycodium and Batodendron) in them which
are neither blueberries nor huckleberries. These plants are
very similar in appearance to the blueberry, when they are dor-
mant and without foliage, and were frequently dug and included
with the blueberry plants. Probably none -of the present plant-
ings are composed wholly of plants which have been carefully
selected for size or quality of fruit.
Thousands of plants were put out in the eastern, central, and
southcentral portions of the state, but no plantings in these
areas have made a growth that could be considered as compar-
able to a well cared for planting in that area of northwestern
Florida where the plants are found growing wild. Such factors
282 Florida Agricultural Experiment Station
as soil variation, soil acidity, and drainage probably account for
these comparative failures, though poor packing and handling of
the plants as they were removed from the woods may have been
a contributing element. In fact, in many instances little or no
care was exercised in the digging, protection of the roots from
exposure to sun or winds, or in the packing of the plants. Many
of them reached their destination in a poor condition and fre-
quently badly dried out, thus adding to the difficulty of procur-
ing a uniform and vigorous planting.
In view of the results obtained in plantings in this state out-
side of the northwestern area, persons located outside of that
district who contemplate the growing of blueberries should con-
fine their first plantings to experimental plots. Within a com-
paratively short time such an experimental planting will de-
termine definitely whether or not blueberries are adapted to
that locality. If the behavior of this trial planting is satisfactory
an acreage can then be planted with some assurance of success.
Should the experimental planting prove to be a failure, however,
the planter will have learned at small cost that his location is
not suited to the culture of blueberries.
At the present time the greater portion of the plantings have
been made in seven counties in northwestern Florida. A careful
estimate* gives the cultivated acreage of plants of all ages in
those counties as follows:
Bay ............-.. .......-- ..- ......... --..- ..-- 450
Escam bia ......... ..-- ..-- .. .--...-- ....---......- ---- ............. 100
Jackson .......-.. .....-..... ....- ..- ..----- -- .......--- .....--.... ---- 100
Okaloosa ..--..--.......-----..... .........----------......----....-.-- ..... 1,200
Santa Rosa --.........-.........-....... ..... ....----........-----..... .... 250
Walton .... ...........-......-- .....- ............... .. ......... 115
Washington ..-.--.......- ----- -----..---..----- .. 10
There are several ,species of blueberries found growing wild
in different parts of the state, but only the tall-growing blue-
berry, usually termed the "Rabbit-eye" blueberry, is considered
as having commercial possibilities. The type of blueberry grown
in New Jersey and elsewhere in the Northern states has thus
far given little promise of being a commercial success in Florida.
*Figures furnished by County Agricultural Agents or Agricultural
workers in the counties mentioned.
Bulletin 194, Blueberry Culture in Florida 283
The blueberry (including the Northern commercial blueberry)
is included in the genus Vaccinium of the family Vacciniaceae
(Small; Britton and Brown), the huckleberry family. The fruits
of the genus Vaccinium have numerous, small, inconspicuous
seeds, differing from the true huckleberry (Gaylussacia spp.) in
which the fruits contain 10 large, hard seeds or nutlets. The
Fig. 113.-A single blueberry plant in its 32nd year from time of
native blueberry of the Florida plantings is probably Vaccinium
virgatum Ait., or a form of V. corymbosum L., the former being
considered by some as a variety of the latter. These species as
found in the wild state in Florida are confined almost entirely
to the extreme northwestern portion where they are locally
termed the "Rabbit-eye" blueberry.* Within the wild species
which are being planted there is a striking variation in foliage,
*Other more or less popular local names applied to these plants are
huckleberry, or Arab, Tree, Swamp, June, and Highbush blueberry.
284 Florida Agricultural Experiment Station
habit of growth, and in size, shape, or appearance of the fruits
and several distinct horticultural varieties will in all probability
be described at some future time.
The mature plants of the Florida blueberry attain a maxi-
mum height of about 15 feet and usually have several stems re-
sulting from the growth of suckers
"- whichh spring up about the base of
the plant. The leaves, which are
olrnally deciduous, vary in shape
tromn ovate to ovate-oblong or ellip-
tic to elliptic-lanceolate. They are
from 1 to 3 inches in length,
4 mostly having serrate or serru-
". late margins. On different
t plants the color and general
S appearance of the foliage varies
S greatly, on some the leaves
S are glabrous and on others
The fruits, borne in
clusters on wood of the
previous season's growth,
S S are from one-quarter to
S eleven-sixteenths inches in
diameter, the average be-
ing three-eighths to seven-
sixteenths inches. In color
the berries are black or
blue-black, some having a
heavy bloom* and others
Fig. 14.-A no bloom. The shape is
Fig. 114.--A t. pi-
cal fruit cluster. generally globular but this va-
ries, ranging from oblate to
ovate, conic, or oblong-conic.
The calyx is persistent and may be widely flaring or almost en-
tirely closed. The flavor generally is excellent but some plants
bear fruits which seemingly have a lower juice content than is
desirable, the fruit from these being somewhat dry or mealy in
texture. This mealiness is seldom as apparent in fruit from older
"*The term "bloom" as used here refers to the white waxy or powdery
coating that is commonly found on the surface of leaves, stems, or fruits
Bulletin 194, Blueberry Culture in Florida 285
plants. To the taste, there is quite a variation in the acidity of
the fruit from different plants even in the older plantings. Part
of this difference may be due to variations in soils, fertilizers,
or cultural methods employed, but as like differences are to be
noted in fruits from plants growing wild it is quite probable
that the cause is quite largely genetic variation.
f -, -
Fig. 115.-Fruits picked at random from several plants, showing variation
in size and shape.
An examination of several samples of fruit showed that the
fresh fruit was about 80 percent water. Approximately 35 per-
cent of the dried fruit was reducing sugar with a trace of non-
reducing sugar, probably cane sugar; indicating that about 7.5
percent, by weight, of the weight of the fresh fruit was sugar.
The fruit examined contained about 0.38 percent acid calculated
as citric acid, though it was not certain that the acid was entire-
ly citric. A comparison of the approximate sugar and acid con-
tent of some of the common fruits based on fresh weight, is
An extract of the crushed fruit was approximately pH 3.5 as
compared with the pulp of oranges which is about pH 3.8 4.0.
The fruit was mealy in texture and there was little free juice
that could be readily extracted.
286 Florida Agricultural Experiment Station
I Cane Sugar Reducing Sugar Acid
Cherries ......... ... ............... 0.0 10.0 0.7
Strawberries ...... .................. 6.0 5.0 0.6
Raspberries ................ ...... 2.0 5.0 1.4
Gooseberries ............. ............... 0.0 6.5 1.6
Oranges .................................... 4.0 4.5 1.0
Blueberries ............ ............ trace? 7.5 0.38*
While the plants grow wild along the banks of streams they
cannot be said to be swamp plants, since they do not grow in
swamps or on other submerged lands. Ordinarily, they are to be
found growing best in locations where the drainage is good
although the location may be occasionally flooded by unusually
high waters. The wild plants in Florida have been reported
chiefly in the northwestern portion of the state, and most of the
commercial collecting has been carried on in Okaloosa, Walton,
and Santa Rosa counties.
The presence of a mycorrhizal root fungus is commonly con-
sidered necessary to the maximum development and thrift of
blueberry plants. The fungus is supposed by many to aid in the
absorption of nutrients by the plant while being in turn par-
tially nourished by the plant. The roots of a large number of
wild and cultivated Rabbit-eye blueberry plants have been ex-
amined and the fungus has been found without exception on
every specimen. It would seem that under like environmental
conditions, those plants having the most vigor would normally
have the greatest amounts of this fungus if it plays as important
a role as is commonly ascribed to it. This has not proven to be
the case with the specimens examined, there being no correla-
tion between growth of the plant and the amount of the fungus.
Wide variation was found in the amount of fungus present but
this variation could not be correlated with the condition of the
plants; some of the very thrifty plants had very small amounts
of the fungus, others a great deal, while some very poor plants
had as much of the fungus as any plant examined.
*Calculated from electrometric titration as anhydrous citric acid with-
out actual identification of the acid.
Bulletin 194, Blueberry Culture in Florida 287
If the presence of this fungus is necessary for the maximum
development of the plants it is quite probable that the roots of
all plants dug from the wild are plentifully supplied. In the
event rooted cuttings are planted, the fungus may be easily in-
troduced by including some roots from old plants with the
roots of the cuttings at the time of planting in the field. Such
roots should be some of the finer fibrous roots and should not
be allowed to become completely dried out in transferring.
According to Beckwith and Coville (2), blueberries require
cross pollination to set a full crop of fruit. Thus a field should
contain plants of at least two inter-planted varieties, to insure
a full crop. At this time this information is of no value to Florida
growers, there being numerous varieties in every planting.
There will probably come a time, however, when only plants of
known parentage will be planted and it will be to the growers'
advantage at that time to know that probably more than one var-
iety should be planted to obtain maximum yields.
The soils on which blueberries are now being grown with
greatest success are largely upland soils of the Norfolk and Tif-
ton series, being mostly of Norfolk sand and sandy loam types
underlaid with a clay subsoil at from one to four feet. Good
drainage is essential to a thrifty growth of the plants and the
most satisfactory results have been attained from plantings
made on medium high, rolling lands having good drainage but
with a subsoil which will prevent excessive moisture loss dur-
ing periods of drought. In large plantings, areas are occasionally
found in which plants are not doing as well as those of the gen-
eral run of planting. An examination of these areas has almost
always revealed poor drainage due to an impervious subsoil
close to the surface and a resulting high water table.
Soil acidity has been found to be the chief limiting factor in
Northern blueberry districts and is quite probably a factor for
the Florida blueberry. Tests made of the soil around wild plants
and in successful commercial plantings gave readings of pH
5.0-5.6 for the first foot, and from pH 5.0-5.2 for the second
foot and third foot. Coville (1) in reporting his work with the
Northern blueberries, states that a soil having a reaction of pH
5.0 is best adapted for the culture of those plants and from the
above figures it will be seen that this figure is at least approxi-
288 Florida Agricultural Experiment Station
mately correct for the Southern varieties now being brought
under cultivation. Nearly neutral soils or those having an alka-
line reaction are probably unfitted for blueberry growing under
ordinary conditions. Obviously, the application of lime or other
materials which will tend to neutralize soil acidity should be
strictly avoided, and soils that have been limed for other crops
should not be planted. Blueberries should be planted upon land
which is known to have a reaction favorable to their growth
rather than attempting to correct the reaction of the soil by
the use of chemicals.
In the use of fertilizers, however, it will probably be desirable
to use materials, when possible, that will tend to increase the
soil acidity. In this regard, sulphate of ammonia will probably
be found superior to nitrate of soda as a source of nitrogen.
Experiments will need to be carried out, however, before defi-
nite recommendations can be made. It is possible that the fail-
ure of some of the plantings made in the central or south-central
part of the state is due to the unfavorable soil reaction.
Blueberries may be propagated by seeds or cuttings or by
suckers which grow up about the base of the older plants. Pro-
pagation by budding is possible but since suckers are produced
so freely from the base of the plant at a point below any possible
bud union the only value of this method would lie in the rapid
production of wood for cuttings. Since plants grown from
seeds will prove as variable as those now planted or growing
wild, propagation from selected plants will have to be by either
suckers or cuttings if the desirable characteristics are to be re-
tained unless breeding is gone into extensively so as to estab-
lish pure line varieties.
The removal of rooted suckers is the easiest and quickest
means of propagation. (Fig. 116.) These suckers should be re-
moved during the dormant season with as much root attached
as it is possible to secure. They may be set directly in the field
or, if small, may be grown for a season in the nursery row. It
should be possible to select enough highly desirable plants from
the present plantings to supply a large quantity of first class
planting material by this method.
Cuttings may be rooted, but it is not possible to obtain as high
a percentage of rooted cuttings as is commonly obtained from
Bulletin 194, Blueberry Culture in Florida 289
. . ...... . ...
Fig. 116.-Sucker growth about the base of a mature plant may be used
for propagating plants that will produce fruit identical with that of
the parent plant.
some other plants. Tests begun four years ago would indicate
that cuttings should be made in the early winter months, after
the plants have become fully dormant, and that only wood of
the current season's growth should be used. This growth will
usually be about the diameter of a pencil and of a very satis-
factory size for handling.
Extreme caution should be exercised in cutting the wood;
only smooth, clean cuts should be made and the wood should
not be allowed to become at all dry between the time of cutting
and insertion in the rooting medium. By wrapping the cuttings
290 Florida Agricultural Experiment Station
in either damp sphagnum moss or burlap as they are cut any
drying out of the wood is easily avoided.
Fig. 117.-Blueberry cut-
t'ngs with root forma-
tion well started.
Two types of rooting media have given fair success. Clean,
coarse sand or a mixture of half sand and half peaty muck were
satisfactory. No appreciable difference between these two media
in the percentage of rooted cuttings was noted. In both cases
the cutting bed was outside, surrounded only by a 12 inch frame
to protect it from the wind. Those cuttings placed in the sand
were from eight to 12 inches long and were inserted approxi-
mately two-thirds of their length; where sand and peaty muck
were used the cuttings were from four to six inches in length.
From five to eight months were required for the starting of any
root growth, although heavy callous formation preceded the ap-
pearance of roots by several weeks. No shade was used until
the weather became quite warm, when the bed was covered with
slats to give a half shade.
The location chosen for the cutting bed must be well drained.
A trench should be opened with a spade or like tool to receive the
cuttings as any attempt to push them into the sand may bruise
the lower end or tear the bark from the wood. After insertion
of the cuttings the sand or other medium should be firmly tamped
about them and at no time should it be allowed to become dry.
Bulletin 194, Blueberry Culture in Florida 291
The cuttings should be left in the frame or cutting bed for one
full season, then transferred, in the early winter, to the nursery
row and grown there to a size desirable for a permanent field
Fig. 118.-Nursery of rooted sucker blueberry plants.
A method described by Coville (1) termed "stumping" also
can be employed. In this method the parent plant is cut back to
the ground level in early spring before growth starts, and the
stump is kept covered to a depth of 3 to 4 inches with a mound
of sandy soil. The soil in the mound must be kept moist and
maintained at a fairly constant level, any soil which is washed
away by rains, being immediately replaced. The sprouts or
shoots, of which there are usually several, grow up through the
mound of soil and later develop roots within it. The rooted shoots
are severed from the parent plant the following winter, each
forming a new plant. The tops are cut back severely at this time
and the plants then placed in a coldframe for a season to de-
velop a good root system. The coldframe is shaded during bright,
Large size, uniformity, and high quality in the fruit is essen-
tial to the creation and maintenance of a good demand. So long
as the markets are only partially supplied, the demand will usu-
292 Florida Agricultural Experiment Station
ally remain more or less satisfactory, but when the bearing acre-
age reaches proportions where markets are fully or over sup-
plied, only the fancy fruit can be expected to bring fancy prices.
Due to the variation of the fruit in the present plantings little
opportunity of grading for shipment, other than for size, is pos-
sible and this is seldom done. If the fruit were sized, it is pos-
sible that the grower could get better prices for his large sizes
and benefit thereby, particularly late in the season. In the future
the plants for setting should be carefully selected for uniform-
ity of fruit, thereby making available to the market a uniform
product of high quality.
The plants are set in the field during the winter months-De-
cember, January, and February. If the plants are set in early
winter, the soil will have become well settled about the roots
and callous formation will have started on the cut portions be-
*L A A1S
Fig. 119.-Blueberry planting in second year after transplanting.
fore the usual spring drought; the plants making a more satis-
factory recovery and growth than if planted late.
The wild plants when dug, usually have few or no fibrous
roots attached and more closely resemble clubs than rooted
plants. The tops should be cut back severely at the time of dig-
Bulletin 194, Blueberry Culture in Florida 293
going. Smooth cuts should be made where the roots are severed
and the roots kept damp during the period of transplanting.
Careless handling in digging and packing has been the cause of
many losses and possibly the failure of some plantings.
The plants in the wild state are usually rooted near the sur-
face of the ground, the rootstock frequently being covered only
with leaves and other organic matter. This is due to the fact that
they commonly occur, in the wild state, on land that is subject
t o overflow
usually has a
hig h water
table for a
a b I e portion
of the year.
The plant con-
must be root-
ed very close
to the surface
in order to
ply of air for
the roots. Be-
he roots. B Fig. 120.-An exceptionally vigorous plant,
cause of the two years from transplanting.
ing habit of the wild plants the impression frequently prevails
that very shallow planting should be practiced, whereas experi-
ence has shown that the plants should be set considerably deep-
er (5 to 8 inches) than they were rooted in the wild state. Cul-
tivation of the soil will give the aeration needed by the roots,
which the plant could get in the wild state only by shallow
Proper planting distances have not, as yet, been determined
accurately, but a 15' x 15' spacing probably should be the mini-
mum. Observations of some of the older plantings in which
there are plants with a spread of 12 to 15 feet, indicate that a
spacing of 18' x 18' is not too great if cultivation is to be main-
tained in mature plantings. More plants per acre can be set with
294 Florida Agricultural Experiment Station
the closer spacing but cultivation undoubtedly will be seriously
hindered when the plants attain their mature size. If desired,
the rows may be spaced 20 feet apart with a closer spacing in
the row, and this will allow for cultivation in one direction for
an indefinite period. Too close planting results in overcrowd-
Fig. 121.-View between rows of a blueberry planting made 32 years ago.
ing, which tends to prevent the plants from reaching their maxi-
mum in size and fruit production.
As yet no comprehensive fertilizer tests have been conducted
on blueberries in Florida. Beckwith (2), in some fertilizer ex-
periments on blueberries in New Jersey, found that a complete
fertilizer composed of nitrate of soda, dried blood, steamed bone,
rock phosphate, and potash, and of an approximate analysis of
4-8-3,* applied at the rate of 600 pounds per acre gave the best
results, this mixture nearly tripling the yield over unfertilized
plots. This analysis will compare favorably with the analyses
approximating 4-8-4 which are now being used in this state. Ap-
plications should be made, in the light of present information, at
*Four percent ammonia, 8 percent phosphoric acid and 3 percent potash.
Bulletin 194, Blueberry Culture in Florida 295
the rate of 500 to 800 pounds per acre, according to the size
and age of the plants, the time of application being in early
spring. It is essential that no lime or other materials that will
Fig. 122.-Mature blueberry plants normally have stems as here shown.
tend to decrease the soil acidity be used, and for that reason,
sulphate of ammonia probably should be substituted for nitrate
To keep down weed growth, help to conserve soil moisture and
give the roots the required aeration, clean and regular, shallow
cultivation should be given during the spring months. Deep cul-
tivation, particularly after the plants have attained some age,
should be avoided. The feeding roots are close to the soil sur-
face and such cultivation may destroy a large portion of them
and thereby damage the plants.
As the sandy soils on which most plantings have been made
usually have a low content of organic matter, a leguminous cover
crop, such as cowpeas, should be grown in the row middles. This
crop can be planted in July without serious interference with
the picking of the fruit, whereas a cover crop planted in the
spring would greatly interfere with the picking and at the same
time be subject to considerable damage itself through being
296 Florida Agricultural Experiment Station
trampled by the pickers. The cover crop can be disked into the
soil during the late winter or early spring.
Little or no pruning has been practiced but some observations
have indicated that severe cutting back of old plants will prob-
ably result in a greatly increased yield in the second or third
year after such pruning. This cutting back will also make pick-
ing somewhat easier as all the fruit will then be accessible from
Spraying has as yet been unnecessary, no serious insect pests
nor diseases having been reported. There are some diseases of
minor importance to be found, these chiefly affecting the foli-
age. One, a rust (Pucciniastrum myrtilli*), is present in most
of the plantings but apparently is of little economic importance,
only a few plants being found infected to any extent in any one
planting. Although these few plants had only a light crop of fruit
this light fruiting could not with certainty be attributed to the
presence of the disease.
The season of ripening begins in late. May or early June and
lasts from 10 to 12 weeks, mid-season being about the first or
second week of July. As the earliest of Northern blueberries do
not begin ripening until late June, it will be seen that the Florida
berries are without competition on Northern markets for at least
three weeks. All the berries do not ripen at once, due in part to
a long blooming season which extends from early February into
March. Normally, but a few berries in a cluster ripen at one
time, which necessitates picking at least once each week. If this
can be considered as a disadvantage, it is partially offset by the
long season which makes the fruit available for nearly three
months and prevents the glutting of markets as would no doubt
occur if large acreages were ripening their fruit within a limited
When large plants are used in planting and a thrifty growth
follows, some fruit will be borne the second year after trans-
planting, but fruit in commercial quantities should not be ex-
pected until the third or fourth year. Thrifty plants should pro-
duce from four to seven quarts of fruit by the fifth or sixth
year, the yield increasing annually until the plants are from
*Identification by Mr. Erdman West, of the Department of Plant Path-
Bulletin 194, Blueberry Culture in Florida 297
12 to 15 years old when they can be considered as mature. If
the planting is properly located and given the required atten-
tion, an average yield of 12 to 16 quarts per plant should be pro-
duced by the 10th to 12th years. These figures are conservative,
as greater yields have been authentically reported. Plants from
11 to 15 years old have produced from 50 to 60 quarts of fruit in
a single season, but such yields are exceptional and plants can-
not be expected to average this in field plantings.
The fruit is marketed in blueberry cups of one quart capacity,
resembling the ordinary strawberry cup but with no wide
cracks at the corners. These are shipped by express in the regu-
lation 24-quart strawberry crate. Trial shipments of 16-quart
crates also have proven quite satisfactory. The fruit carries to
Northern cities in good condition, without icing, provided prop-
er attention is paid to picking, packing, and promptness in ship-
ment. It should be shipped on the same day as picked, as delay in
shipment after picking may cause it to arrive at destination in
Women and children do most of the harvesting of the crop,
such labor picking from 20 to 30 quarts per day. The fruit is
picked as soon as it ripens, this condition being denoted by the
color which, in ripe fruit, is blue or black. At the time of picking
the surface of the fruit must be free from moisture to insure
minimum loss from decay in transit. Some growers, by using
care when picking to exclude leaves and green or immature
fruit, do not repack for shipment, others use less care in pick-
ing, preferring to cull the fruit in a packing shed. Either method
is satisfactory provided only clean and mature, but not over-
ripe fruit is included. No general attempt has been made, as yet,
to grade the fruit for size or quality. It is quite probable that
were the berries graded according to size that the larger fruit
would bring a premium on all markets.
(1) CovILLE, FREDERICK V.
1921. Directions for Blueberry Culture, U. S. D. A. Bulle-
tin 974, 24 p., illus.
(2) BECKWITH, C. S. AND COVILLE, S.
1927. Blueberry Culture, New Jersey Agr. Expt. Sta. Bul-
letin 200, 28 p., illus.