Bulletin 22 October, 1919
COOPERATIVE EXTENSION WORK IN
AGRICULTURE AND HOME ECONOMICS
UNIVERSITY OF FLORIDA DIVISION OF AGRICULTURAL
EXTENSION AND UNITED STATES DEPARTMENT
OF AGRICULTURE COOPERATING
P. H. ROLFS, Director
THE SILO IN FLORIDA
By W. H. BLACK*
The increased interest in the live stock industry during the
last two years is shown by the introduction of over 3000 good
breeding beef cattle and a good number of dairy cattle. It
has been clearly demonstrated that the cattle brought in from
other sections of the United States cannot be turned on the range
for the entire year and make gains in weight. The common cat-
tle of Florida have been subjected to these conditions, and while
they have been able to survive they have not developed any
appreciable size. The prices being paid for this class of cattle
Fig. 1.-Silos on the Wenalden Farms, Zellwood, Fla.
*Working cooperatively with the Bureau of Animal Industry, U. S.
Department of Agriculture, in Beef Cattle Extension Work.
2 Florida Cooperative Extension
are proving to the beef producers that they are not delivering
the right kind of goods. A higher quality of beef is in demand.
As land values and taxes increase, a better grade of cattle must
be produced in order to meet the demand and keep pace with
the increased cost of production. The live stock men are realizing
this fact which is the reason for the rapid introduction of well
Beef, pork, milk or mutton can be produced more econom-
ically by good pastures than by other means. There is a time
however, even in Florida, when pastures cannot be depended
upon to furnish the necessary amount of roughage. The pastures
have room for improvement, but generally speaking there is good
pasture for beef cattle in Spring, Summer and Fall. From the
middle of December to the middle of March, there is a shortage
of pasture, and cheap feed in the form of succulent roughage
should be supplied by other means. The most economical and
satisfactory way to do this is with the silo. For the dairy herd
a silo will be found valuable for a greater period of the year. A
silo is nothing more than a large air-tight can or container for
the purpose of storing in a succulent condition roughages such
as corn, sorghum, cane, cowpeas, or soy beans. The primary
object then in having a silo, is to be able to have a supply of
succulent feed when pastures cannot be relied upon.
THE NEED OF A SILO
Those contemplating building silos should be familiar with
the advantages offered by them, and then determine whether suf-
ficient live stock is kept to warrant their use. If the size of the
herd is small, the class of cattle should be taken into considera-
tion. The dairy cow producing milk can utilize to advantage a
ration having a greater proportion of silage than can the fatten-
ing beef animal.
For a dairy herd of at least ten head, silage has been found
indispensable. Dairymen have learned long ago that by using
silage the milk flow can be more economically maintained for
most of the year than by other means. For beef production, for
wintering stockers and feeders, and for the breeding herd, silage
furnishes the most economical roughage. For best results it
should be supplemented with a nitrogenous concentrated feed
such as cottonseed meal, peanut meal or velvet beans. In addition
to being a good feed for all classes of cattle, it has been found
to be very valuable in sheep feeding and also good for the brood
The Silo in Florida 3
sow and mare. Silage should be fed cautiously to a horse, as
moldy silage will usually cause poisoning, often resulting fatally.
A silo would not be practical on a strictly hog or horse farm.
It is necessary that a certain amount or depth of silage
should be removed from the silo daily in order to prevent the
exposed silage on top from becoming moldy. Not less than 21
and preferably 3 inches of silage should be removed each day.
The number of cattle to be fed and the diameter of the silo are
the factors which determine whether or not sufficient silage can
be used to prevent spoiling.
FACTORS DETERMINING CAPACITY OF SILO
The diameter of the silo should be in direct proportion to
the size of the herd. By knowing the size of the herd, the amount
of silage the cattle can utilize, the depth of silage which should
be removed daily, and the length of the feeding period, the
dimensions of the silo needed to give the required capacity can be
readily determined. Table 1 shows capacity in tons of various
TABLE 1.-Capacity in tons of silos of various heights and diameters
Height Inside Diameter
Feet 10 | 11 1 12 ] 13 ] 14 1 15 16 ) 17 ) 18 ) 20
20 I 26 ......... .................. ...-.... -- ......... .....
22 30 36 ....-- --...... ..- - -......... -..... ....... .... .....
24 34 41 49 ......... .. ............... . ... ... .
26 38 46 55 64 ................... ...... ......
28 42 51 61 71 83 ......... ......... ...
30 47 56 67 79 91 105...........
32 51 62 74 86 100 115 137 .............--
34 -...............- 80 94 109 126 143 161 .........
36 .......... ....... 87 102 119 136 155 175 196 .
38 ......... .... 94 110 128 [ 147 167 189 212 261
40 .......... ........ 101 .......... 138 158 180 203 228 281
42 ............................... .. 148 170 193 218 245 300
44 ..... -- -........ .... ...... .. .... 182 207 234 262 323
46 ............. .......... .. .. ..... 194 221 250 280 345
48 .......... ... ....... .. 368
50 .................... ......... ....... ....... 382
For example suppose a dairyman had 25 head of cows and
wanted to feed them 40 pounds each per day, for a period of 180
days. This would mean the feeding of 1,000 pounds, or a half
ton per day.
FINDING THE DIAMETER
What must be the diameter of a silo to furnish 1000 pounds
of feed a day in a depth of 21/2 inches or more? The weight of
4 Florida Cooperative Extension
a cubic foot of silage and the area of the surface of the silo must
be known. The weight of a cubic foot of silage in a silo will
vary according to the depth of the silage. A cubic foot taken
at the top will weigh about 20 pounds and the weight will
increase as the depth of silage increases. It has been found
when there are 30 feet of silage that the average cubic foot will
weigh about 40 pounds.
The area of the surface in square feet may be obtained by
multiplying the square of the diameter by .7854. Where the
diameter of the silo is 12 feet there will be 113 square feet of
surface (12 X 12 = 144; 144 X .7854 = 113 sq. ft.). If there are
40 pounds of silage in one cubic foot there will be 40 times 113
or 4520 pounds of silage in a depth of 12 inches, or 1000 pounds
in a depth of 2.65 inches. If the silo had a diameter of 14 feet
there would be 6160 pounds in a depth of 12 inches or 1000
pounds in a depth of 1.94 inches.
In this instance then where 25 head of cattle were to be
fed 40 pounds per day and at the rate of 21/2 inches or more per
day, the silo 12 feet in diameter would be preferable to one
having a larger diameter. With larger diameters the silage
would not be removed the necessary depth each day to prevent
spoiling of the exposed silage.
DETERMINING THE HEIGHT
Knowing the diameter of the silo, which can be determined
as shown by the number of cattle kept and the amount you wish
to feed daily, the next thing to settle is the height. The necessary
height then can be readily determined by the length of feeding
Until recently few silos have been built with a height more
than three times their diameter. During the last year several
have been constructed with a height four times the diameter.
With all kinds of silos excepting wooden, a height not to exceed
four times the diameter should be considered as safe.
If a silo 12 feet in diameter will furnish 40 pounds of silage
in a depth of 2.65 inches to 25 head of cattle daily, what must
be the height of this silo to hold enough feed for 180 days?
Feeding 25 head of cattle 40 pounds per day means 1000
pounds daily or 180,000 pounds or 90 tons for 180 days. By
referring to Table 1, it is seen that a silo 12x38 will hold 94
tons, a little more than is actually required, but this additional
capacity may prove a good investment.
The Silo in Florida 5
By referring to Table 2, it is seen that where 40 pounds of
silage are fed per head daily at a rate of 3 inches of depth, that
28 head of cattle can be fed from a silo 12 feet in diameter.
This corresponds very closely to 40 pounds daily for 25 head,
removing the silage at a depth of a little over 21 inches daily.
TABLE 2.-This table shows relative number of cattle that may be fed
from silos of different diameters when 3 inches of silage are removed
daily, allowing 40 pounds per cubic foot.
SNumber of Cattle That May Be Fed
S. i Allowing
n 'S I40 Lbs. 35 Lbs. 30 Lbs. 25 Lbs.
W g |' Daily Daily Daily Daily
10 785 19 22 26 31
12 1130 28 32 37 45
13 1330 33 38 44 53
14 1540 38 44 51 61
15 1770 44 50 59 70
16 2070 50 57 67 80
17 2270 56 64 75 90
18 2570 64 73 85 102
20 3140 78 89 104 125
RELATION OF SIZE OF HERD TO DIAMETER OF SILO
Table 2 shows the number of cattle that can be fed on
40, 35, 30, and 25 pounds silage daily when 3 inches are re-
moved, in silos of varying diameters. From this table the number
of cattle that can be fed 50, 20, 15, and 10 pounds daily can be
determined at a glance. For example in a silo having a diameter
of 12 feet, and where 3 inches are removed daily, 37 head of
cattle can be fed 30 pounds daily. Twice the number, which
would be 74, could be fed 15 pounds daily, or 111 head, ten
REQUISITES OF A GOOD SILO
After the necessary size is determined, the requirements of
a first class silo should be considered. In the first place the silo
should have a foundation and walls impervious to both air and
water. If air can be excluded from the silage and loss of moisture
be prevented thru the walls, the stored product will be of good
quality regardless of whether the container or silo is made of
wood, steel, concrete, or hollow blocks.
Durability, cost of construction, upkeep and availability of
material are factors which should be carefully considered before
deciding on which type or kind is best. These factors will be
discussed in a general way under each type of silo.
6 Florida Cooperative Extension
TYPES OF SILOS
There are many types of silos, but in a general way they
may be divided into two general classes, above ground silos and
pit silos. Those of the first class will be given more considera-
tion, because of their adaptation to any part of the state. The
pit silos can be used only in certain sections of central, northern
and western Florida where the soil is very firm and the water
table low enough to permit such an excavation.
The percentage of wooden silos in use in the United States
is greater than any other kind. The reason for this is because
there was an abundance of suitable lumber and people were more
familiar with its use than with other materials. Of late years
there has been a rapid advance in the use of concrete and clay
products for all kinds of construction, and because of the greater
durability of structures made from these products they are
becoming more and more popular. There are many locali-
ties tho, where conditions still warrant the construction of
wooden silos. Many live stock
men have their own saw mills
and own large tracts of pine and
cypress timber. In such cases
the lumber can be milled reason-
ably and a good silo erected very
The best woods for silo con-
struction, so far as durability is
concerned, are California red-
wood, cypress, and Oregon fir.
The red-wood and fir should not
be considered in this state, due
to the great expense in getting
them here. So far as wood is con-
cerned the choice in Florida
should be between cypress and
Cypress should rank first. The
.. initial cost would be more than
Fig. 2.-Modified Wisconsin Silo on one built of pine, but when dura-
Farm of J. C. DeBevoise, Jack-
sonville, Fla. ability is taken into consideration
The Silo in Florida 7
the cypress would be the more economical. A cypress silo prop-
erly built of selected material and well taken care of, should last
at least twenty years. A pine silo under the same conditions
would do well to last half as long.
Cypress silos are built in three types, either with vertical
staves, horizontal siding, or a combination of both.
The Modified Wisconsin silo, built of cypress, Fig. 2, should
prove a popular type of wooden silo.
Such a silo is made by erecting 2x4 studding vertically on a
good foundation, and sheeting the inner side with two horizontal
layers of sheeting (1/x6 inch material), with a course of acid
proof building paper between.
This makes a strong and durable silo. In some cases a
course of sheeting is placed horizontally on the outside of the
2x4 studding. This adds much to the appearance and some to
strength, but where economy is sought in preference to at-
tractiveness this outer sheeting may be omitted.
The common vertical stave silo made of 2x4 or preferably
2x6 inch tongue and groove cypress or pine, makes a good silo.
The ease of construction and the available supply of suitable
lumber has made this type the most popular in the past.
Hoops of either wood or iron may be used. Wooden hoops
are preferable because of their ability to expand and contract
Fig. 3.-Stave Silos on Farm of L. K. Edwards, Irvine, Fla.
8 Florida Cooperative Extension
along with that of the walls of the silo. If steel or iron rods are
used they should be tightened in the summer when the boards
shrink and possibly loosened when the silo is filled. If this is
not done the hoops will fall down during the summer and the silo
will twist out of shape. A stave silo once twisted out of shape
can never be put back perfectly.
Fig. 3 shows stave silos with iron hoops, and Fig. 4 one
with wooden hoops.
Fig. 4.-A patented Cypress Silo on the Tampa Stock Farm, Tampa, Fla.
The following specifications show the necessary material
for a common vertical stave silo 14x32 feet.
Similar bills of materials for most all sizes of silos shown in
Table 1 of this bulletin, can be furnished on request.
BILL OF MATERIAL FOR A STAVE SILO*
Dimensions 14 by 32 feet (above foundation); capacity 110 tons (no
allowance made for settling).
(Proportions 1 part cement, 3 parts sand, 5 parts stone)
Cement Sand Stone
Foundation wall, 1 by 3 feet.........-..........23 bags 2.64 cu. yds. 4.36 cu. yds.
Floor, 4 inches thick...----------............................. 8 bags .89 cu. yds. 1.46 cu. yds.
Total ---................... ................... 31 bags 3.53 cu. yds. 5.82 cu. yds.
92 pieces 2 by 6 inches by 14 feet, and 92 pieces 2 by 6 inches by 18
feet, for staves.
24 lineal feet 2 by 4 inches, dressed, in 2 feet lengths, for door cleats.
*Furnished by the B. A. I. of the U. S. D. A.
The Silo in Florida 9
8 pieces 2 by 6 inches by 10 feet, for rafters.
1 piece 2 by 4 inches by 12 feet, for door frame in roof.
300 feet B. M. 1 by 6 inches, for roof boards.
12 pieces 2 by 4 inches by 12 feet, for stakes for foundation form.
200 feet B. M. % by 6 inches, for foundation form 1 foot above ground.
Hoops (14 in number)
8 %-inch rods 12 ft. 3 in. long, ends threaded 6 inches, hexagon nuts.
32 %-inch rods 12 ft. 3 in. long, ends threaded 6 inches, hexagon nuts.
16 %-inch rods 12 ft. 3 in. long, ends threaded 6 inches, hexagon nuts.
8 %-inch lugs.
32 %-inch lugs.
16 %-inch lugs.
3 squares prepared roofing.
48 bolts % by 6 inches with nuts and washers, for door cleats.
6 eye bolts % by 24 inches, bent up 3 inches on straight end, for anchor.
6 square-headed bolts % by 4 inches, with nuts and washers, for anchor
25 pounds 40-penny spikes.
5 pounds 20-penny nails.
5 pounds 8-penny nails.
92 splines 2 by 5% inches.
Foundation wall 1 foot thick, 3 feet deep, 13 feet inside diameter.
Floor 4 inches thick, 2 feet below top of foundation wall. The staves must
be straight, and of straight-grained, clear, well-seasoned lumber, without
sap, large or loose knots, waney edges, or shakes, and should be dressed.
No allowance is made in this bill of material for scaffold or chute. Roof
is octagonal, 7 inch rise to 1 foot. Staves are set 6 inches from inside of
foundation wall. Silo has 6 doors, 2 feet 6 inches high, 2 feet 9 inches
apart, first door 1 foot above foundation. Heaviest hoops between first
and second doors from bottom.
Inside wall must be given a coat of raw coal tar thinned with gasoline
to the consistency of paint; applied with a brush. This should be done 2
weeks before silo is filled, if possible. See Farmers' Bulletin 589 for com-
The patented cy-
press silos illustrated
in Figs. 4 and 5 are
quite popular thru-
out the South. The
silo shown in Fig. 4
consists of a three-
ply wall having two .
courses of vertical
staves (1x6 inch ma-
terial) with a layer
of asphalt felt be-
tween. These staves Fig. 5.-Cypress Silos on the Komoko Farms,
c o m e in sections Newberry, Fla.
10 Florida Cooperative Extension
which make this type very easily constructed. The silos shown in
Fig. 5 consist of a combination of vertical staves and horizontal
siding, all made of cypress. The vertical staves are made of 2x6
inch material and make the inner wall of the silo. An acid proof
paper surrounds these staves and this in turn is bound by an
outside wall of horizontal siding of /x6 inch material.
All vertical wooden stave silos should be properly anchored
by three strong wires. The life of the inner walls of all wooden
silos can be lengthened considerably by the application of a coat
of coal tar or asphalt paint each year.
CONCRETE AND CEMENT SILOS
There are three types of concrete and cement silos, the solid
wall or monolithic; the cement block; and the cement stave. A
concrete silo properly built should last indefinitely. The initial
cost may exceed that of a pine silo, but when the life of it is
considered this slight excess in cost is a negligible factor.
In some sections of the state there is an abundance of all
material excepting the cement. A few localities are short of both
rock and suitable sand, but these can usually be found at no
great shipping distance. In reality there is a home supply of
materials with the exception of cement.
The Monolithic Type
The monolithic has proven the most popular of the cement
silos. This type is a solid wall of concrete, usually built six
inches in thickness and reinforced with steel. Its durability is
its strong feature. Fig. 6 shows twin monolithic silos. Such a
silo can be erected with less skilled labor than other types of
cement silos, most wooden silos, or those made of clay products.
One man thoroly skilled in concrete and cement work and steel
reinforcement can put up a silo of this type with only common
labor. Mixing the concrete properly and in the right proportions
and properly reinforcing with steel are the essentials to be
considered in the construction of this type. It requires skilled
labor to build the wooden forms, but this can be overcome by
using metal forms, which can usually be rented from construction
The floors and foundation should be made of a mixture of
1:3:6 or 1:21/2:5; that is, a mixture of one part cement, with the
sand and crushed rock in the proportion of 3 to 6 or 21/ to 5.
The wall should be of a mixture of 1:3:5 or 1:21/. :4. The ma-
The Silo in Florida 11
trials should be of the best quality. The cement should be fresh
and of the highest quality on the market. The sand should be
clean and coarse. The coarser material should be gravel or
crushed stone, the latter being preferable. Stone or rock should
not be more than 212 inches in diameter for use in the foundation,
nor larger than 2 inches for walls. A mixture of pieces from
12 to 2 inches makes a very strong wall.
The inner walls of all masonry silos should have an appli-
cation of cement wash or coal tar preparation each year at the
time of filling. This can best be done by doing a few feet at
a time while the silo is being filled.
Fig. 6-Concrete Silos on the Loxahatchee Farms West Palm Beach Fla.
12 Florida Cooperative Extension
BILL OF MATERIALS FOR A CONCRETE SILO*
Inside dimensions 14 by 32 feet; capacity 100 tons
(Proportions: 1 part cement, 3 parts sand, 5 parts stone)
Concrete Cement Sand Stone
Footing and body of silo...............---28.9 yds. 136 bags 15.7 yds. 25.5 yds.
Floor, if needed................................. 1.9 yds. 9 bags 1.1 yds. 1.7 yds.
Total, including floor.............-- .........30.8 yds. 145 bags 16.8 yds. 27.2 yds.
15 pieces woven wire fencing 46% feet long, 36 inches wide, double
lower 3 courses.
5 pieces 2-inch angle iron 2 feet long for door sills.
10 pieces strap iron 4% feet long for door sides.
(Cord, 2 feet 8% inches)
Inside form: Rings, 16 pieces 1 by 6 inches by 12 feet; studding, 16
pieces 1 by 4 inches by 12 feet; sheet iron, No. 20 or 22, 4 pieces 36 inches
by 11 feet 2 inches.
Outside form: Rings, 16 pieces 1 by 6 inches by 14 feet; studding, 16
pieces 1 by 4 inches by 12 feet; sheet iron, No. 20 or 22, 4 pieces 36
inches by 12 feet 3 inches; strap iron, 24 pieces % by 1 by 24 inches, bent
to curve of outside form and drilled for 4 rivets of 7 pound size; 2-inch
right angle turned up one end and drilled for %-inch bolt.
100 tinner's rivets of 7 pound size.
1/ package tinner's rivets, 1% pound size.
12 machine bolts % by 6 inches, long threads.
Roof and Doors
Plates, 8 pieces 2 by 6 inches by 14 feet.
Rafters, 8 pieces 2 by 6 inches by 10 feet.
Sheating, 300 feet B. M. of 1 by 6 inch stuff.
1 piece 2 by 4 inches by 12 feet for door frame in roof.
3 squares prepared roofing or 2,400 shingles.
10 bolts 1/ by 18 inches, with nuts and washers.
60 feet B. M. tongue-and-groove flooring for doors.
35 square feet waterproof paper for doors.
2 door forms, 1 piece 2 by 6 inches by 16 feet; 2 pieces 2 by 3 inches
by 10 feet.
20 pounds 8-penny common wire nails.
30 pounds 10-penny common wire nails.
5 pounds 20-penny common wire nails.
It is expected that extra care will be taken to have the walls smooth,
so that no plaster coat will be needed. If possible, build the silo so the
walls can season a month or more. Give the inside wall a good coat of raw
coal tar dissolved in gasoline. Stone should be of a size that will pass
through a 1 inch ring. For scaffolding use any material on hand, or poles
and 1 by 4 inch stuff. If outside ring of wood is omitted, use No. 18 iron,
and in such case the outside form may be built in two pieces and only 12
pieces of strap iron will be needed. If no more than two silos are to be
built with form use black iron; otherwise use galvanized iron. Reinforcing
wire should be heavy, top and bottom wires not less than No. 9, and should
be started in the footing. Dimensions of footing 18 inches wide, 9 inches
thick. Floor 4 inches thick.
"*Furnished by B. A. I. of U. S. D. A.
The Silo in Florida 13
Cement Block and Cement Stave Silos
Hollow cement blocks (Fig. 7) have been used for silos with
good satisfaction, but the cost of construction runs higher than
the monolithic type and therefore this type has not become so
Cement stave silos are increasing rapidly thruout the corn
belt and are being built in Mississippi, Colorado and Texas.
Where sand is plentiful and gravel and stone scarce this type
should become very popular.
Fig. 7.-Concrete Block Silo on the Ocala Heights' Dairy Farm, Ocala, Fla.
Either the hollow cement block or cement stave will cost
more than the monolithic type, if all materials are available.
However, where coarse material for the bulk of the concrete is
not at hand and where sand is available, the cement stave would
possibly be the cheaper.
At the present time there are no cement stave factories
within a reasonable shipping distance. Florida conditions should
warrant such a factory.
CLAY PRODUCT SILOS
There are two types of silos made from clay products, the
brick silo and the hollow block. Fig. 1 shows a brick silo in
process of construction.
Silos made of common brick have been quite satisfactory in
the past. Their greatest difficulty has been the lack of reinforce-
14 Florida Cooperative Extension
ment. The cost of brick in this state and the difficulty in properly
reinforcing has kept this silo from becoming popular.
The hollow clay block silo has possibly increased in popu-
larity thruout the corn belt more rapidly than any other kind of
silo. Like concrete, it is
strong and durable and when
properly constructed it s
walls are smooth and imper-
vious to water and air. This
type is one of the most at-
tractive and is shown in Fig.
8. The cost of construction
will run somewhat higher
than the concrete, as more
skilled labor is required. It
is necessary for one good
man to look after the mixing
of cement and another to lay
This type, like the cement
stave, will become a popular
silo in Florida only when
factories for making the
Fig. 8.-Twin Patent Hollow Clay
Block silos on the Farm of F. N. blocks and staves are in ope-
Burt, DeLeon Springs, Fla. ration closer to us.
Metal silos have been used in the
United States for about twelve years,
and in most cases have'proven satisfac.-
tory. The commendable features of the
steel silos are that they come in large
sections and can be constructed easily;
they are strong, durable, and can be
easily anchored. The sections are over-
lapped and interlocked and held to-
gether with bolts. This type of silo is
shown in Fig. 9.
They have met with some dissatis-
faction in the past because of a chemical
action between the acid of the silage
and the steel walls. This is overcome Fig. 9.-Steel Silo on the
Farm of B. C. Datson,
now by giving the inner walls of the Orlando, Fla.
The Silo in Florida 15
silo a coat of specially prepared asphaltum paint each year before
filling the silo.
The metal silo is well adapted to the warm climate of Flor-
ida, and also to the arid regions where the extremely dry climate
is trying on wood.
The pit silo is a popular type in certain sections of the
United States, particularly in the south and southwest. It is
adapted only to those localities where the soil is very firm and
where the water table is down several feet. In the western
part of this state there are sections where the soil is a very firm
clay to a depth of 20 to 60 feet, and in such places the pit silo
has become popular.
This type of silo should be put in on high ground and may
safely run to a depth of two feet above the highest ground water
level. Where the soil conditions are favorable and the water
table low enough to permit a pit of necessary depth without
being endangered by seepage of water, the pit silo is worthy of
This type of silo, where feasible, offers an advantage over
the above ground silo in that it can be put in at less cost. Cheap
labor can be used for digging and at odd times when other work
is slack. Many who have put in pit silos in the past claim that
the work can be done for $1 per foot of depth. Under present
labor conditions the cost would run from $2 to $5 per foot
of depth, depending upon the depth and diameter of silo and
whether or not the walls are cemented or plastered. Most of
the silos have their walls plastered and have a concrete collar
at the top extending about two feet above and three feet below
ground. When such a collar is made the inside diameter must
be the same as the diameter of the pit below, so that the walls
will be smooth from top to bottom.
Because of cheapness this type can be put in by farmers
of small means and by renters. Less power is required to fill
this silo as a blower attached to a cutter is not necessary.
Blowers are expensive and require at least one half the power
to run them. Silage will keep just as well in pit silos as in any
other kind. There are no hoops to tighten, no anchors to watch,
no danger of blowing over or being struck by lightning.
The most commendable feature is their cheapness and the
16 Florida Cooperative Extension
greatest objection is the labor required in removing the silage.
Most farmers with means prefer an above-ground silo. They
would rather buy a larger ensilage cutter and blow the silage
up when filling the silo than raise the silage up from a pit at
time of feeding. The pit silo adds nothing to the appearance of
a farm while a nicely constructed above-ground silo is a structure
that adds much to the attractiveness of the farm.
When considering the construction of a silo one should
become familiar with the cost of the various types. Silos vary
considerably in cost, depending upon the material with which
they are made. Material for a silo 14 by 30 with a capacity of
91 tons, will cost about as follows at present: For a pine stave
$350; for a monolithic concrete $400; modified Wisconsin cypress
$500; patented cypress $550; patented hollow clay block $600;
and for the galvanized steel about $700. The cost of construction
will vary from $200 to $300.
Actual costs have been secured on some silos built on Flor-
ida farms and are shown in Table 3.
TABLE 3.-Actual Cost of Silos in 1917 and 1919; Estimated Cost of a
Kind of Silo .W .
0 U 00
Concrete ............................... 1919 12x50 134 $ 853.60 $ 800.00
Patented hollow clay block 1917 14x40 138 883.90 975.00
Common hollow clay block 1917 14x30 91 650.00 825.00
Patented cypress ................ 1919 15x36 134 950.00 950.00
Steel ........................................ 1917 14x54 200 1060.00 1100.00
Pine ......................................... 1917 14x30 91 450.00 600.00
Foundations for all silos should be carefully constructed
and should be built of concrete, stone, brick, cement block, or
hollow clay block. The foundation should be broad and firm
enough to prevent any cracking or settling. The necessary width
The Silo in Florida 17
will depend upon the type of soil upon which the silo is to rest.
In loose, sandy soils the base of foundation should be 24 to 36
inches wide, while in clay soils 10 to 15 inches should be suffi-
cient. In Florida the foundation should extend to a depth of 2
feet below the surface of the ground; in colder climates a depth
of 4 to 5 feet is necessary in order to get below the frost line.
The inside diameter of the foundation wall should be the same
as that of the silo proper, in order to make a straight smooth
wall from top to bottom of the silo so as to allow proper settling
of silage and prevent any air space which might be formed by
a shoulder at the junction of the foundation and silo wall.
Concrete ranks first as a foundation material. Cement blocks
and hollow clay blocks are good if the holes at the ends of the
blocks are filled up with concrete.
The foundation should be properly reinforced with steel
rods or wire, as not only the weight of the walls of the silo must
be supported but also a large portion of the weight of the silage.
In firm clay soils floors are not absolutely essential, but
when they are used the bottom silage can be removed more easily.
When the ground is moist or seepy a concrete floor is a very
essential feature. Where this condition exists a tile drain should
be placed underneath the floor and extended out to a point
lower than the bottom of the silo. This will keep the foundation
wall and floor dry, and thus add strength to them. It is advisable
to connect the tile drain with a drain in the center of the floor
in order to take out any water that might come in thru an open
door while the silo is empty or thru the top where there is no
roof. However, the drain from the center of the floor should be
plugged when the silo is in use.
Too much emphasis cannot be placed on the construction of
the doorway in a silo. Faulty construction at this place has
been a common weakness of many silos in the past. Because of
improper reinforcement at this point many silos have spread
open at the doorway.
The doors in almost all types, with the exception of the
steel silo, are made of two courses of wood and constructed in
such a way as to fit perfectly and exclude air. They should be
large enough to allow easy entrance for a man, and should be
18 Florida Cooperative Extension
close together so that in removing silage it will not have to be
lifted any great distance.
Continuous doors are becoming very popular, in both patent
and home made silos.
Chutes are almost a necessity to a silo. Their purpose is
two fold: to prevent the scattering of silage when removed from
the silo and to protect the doors from the weather. Wagons or
feed carriers can be placed under the chutes and loaded very
Wood is used more than any other material in building
chutes. Steel, monolithic, cement block, and clay block silos are
now built with chutes made of the same material as the silo
proper. Chutes made of these materials are superior to wood,
being fire-proof and more permanent. Fig. 5 shows a wooden
chute on the center silo opening into the feed room. Fig.
6 shows a concrete chute on monolithic silo which was built
at the same time as the silo. Fig. 8 shows wooden chute on
twin hollow clay block silos, and Fig. 9 shows steel chute on a
steel silo. A window should be placed at the top of the chute.
Roofs are not absolutely necessary in many localities, but
nevertheless are a very desirable feature. A silo without a
roof appears unfinished. In localities having much rain the
roof is a very important feature. If properly put on it will add
strength to the silo, particularly if it is a wooden silo. Roofs are
made of practically all kinds of building materials, such as pre-
pared roofing, tile, wood, either plain or shingled, steel, hollow
block or concrete. The most popular types of roofs are the
conical, and the hip or gambrel. Dome roofs built of concrete,
tile, or clay block are being used extensively in some localities.
The dome and gambrel roofs while somewhat more difficult and
expensive to build, will add a few feet to the height of the silo
and increase the capacity. Figs. 1 and 3 show conical shingled
roofs; Fig. 4 shows a roof made of boards and not covered with
shingles; Figs. 6 and 8 show gambrel or hip roofs made of
prepared or combination roofing; Fig. 9 shows a steel or metal
roof; Fig. 7 shows a concrete roof.
The roof must have a door to admit the carrier or blower
pipe from the silage cutter. A trap door is most often used.
The Silo in Florida 19
A window used as a trap door is very efficient as this will
permit light and eliminate the use of a lantern when removing
silage. Dormer windows are becoming very popular. While they
add a little to the appearance of the silo they are more expensive
and no more efficient. Figs. 3, 7 and 8 show dormer windows,
while Fig. 6 shows the trap door type.
PROTECTION AGAINST LIGHTNING
As silos are generally higher than other farm buildings,
and as lightning usually takes the path of least resistance and
strikes the higher objects, it is quite necessary that protection
be furnished. All masonry silos if reinforced properly, are com-
paratively free from this source of danger. Wooden silos have
no steel reinforcement and are therefore in constant danger
unless properly wired.
LOCATION OF SILO
In determining the place where the silo is to be erected,
convenience should be the deciding factor. It should be con-
veniently situated, so that it will be easily accessible at time of
filling. There should be ample room for the placing of the cutter
and engine at time of filling and for wagons to get up to and
away from the cutter easily and quickly. A great deal of valuable
time can be wasted by wagons having to be backed out from the
cutter. Besides being easily accessible at time of filling, it should
be conveniently located to save labor and time in feeding the
The most popular location for the silo on a dairy farm is
just a few feet from the dairy barn, with the chute of the silo
opening into the feed alley of the barn. (See Fig. 4.) On a beef
cattle farm where the silage is generally fed in troughs out-
side the barn, the better location is to have the silos away from
the other buildings and arranged so that a wagon can be driven
under the chute. (See Fig 8.)
CROPS FOR THE SILO
Corn, sorghum and Japanese cane are the principal silage
crops in Florida. Cowpeas, velvet beans and soy beans make
good silage, but because of the fact that these crops can be
utilized without waste, either as a pasture crop or as cured hay,
and because more labor is involved in getting them thru the
silage cutter, they are not so popular as corn, sorghum and cane.
20 Florida Cooperative Extension
Cowpeas and corn grown together and put into the silo is
becoming a popular practice. Velvet beans have been used in a
like manner, but the difficulty in handling the long tangled vines
and getting them thru the cutter has kept this practice from
Mixtures of corn and cane and of corn and sorghum have
been successfully used. Where this method is used both crops
should be planted so as to reach the right stage for silage at the
same time. Cane or sorghum with corn will not make a better
silage than corn alone, but on the other hand, cane and sorghum
silage is improved by the addition of corn. Table 4 shows the
digestible nutrients in a hundred pounds of various kinds of
silage (taken from Henry and Morrison's "Feeds and Feeding").
TABLE 4.-Feeding Value of Silage
Digestive Nutrients in
Kinds of Silage ,
Corn ...........................------------. 26.3 1.1 15.0 0.7 1:15.1
Sorghum ....................... 22.8 0.6 11.6 0.5 1:21.2
Japanese cane .............. 22.4 0.6 11.2 0.3 1:19.8
Sorghum and cowpeas 32.3 0.9 16.6 0.6 1:20
Cowpeas ...........---- 22.0 1.8 10.1 0.6 1:6.4
Soy bean .........-..... ..... 27.1 2.6 11.0 0.7 1:4.8
Corn and soy bean...... 24.7 1.6 13.8 0.8 1:9.8
In looking over Table 4 it is evident that cowpeas and soy
beans make a more nutritious silage than the crops most gen-
erally used. Such forage crops as corn, sorghum and cane can
be more completely utilized by putting them in a silo. Less
labor will be required in making silage of these crops and less
acreage will be required to furnish the necessary amount of
feed to fill a silo. Corn is the most popular silage crop in all
sections. There are localities in Florida where corn will not
make a satisfactory yield and it is in these places that either
sorghum or cane will be a very desirable crop to grow for silage.
Some of these silage crops will grow in every part of the state.
TIME TO HARVEST
Matured plants make better silage than immature, since
the dry matter and food ingredients increase more rapidly as
The Silo in Florida 21
the plant reaches maturity. Immature plants contain more
moisture and acid and are therefore less nutritious. The crops
should not be allowed to become thoroly ripe as the fodder will
become woody and will not be so palatable or digestible. Over-
ripe fodder requires more power to cut, more labor to tamp it
in the silo, and the addition of a large amount of water to the
silage at time of filling. Corn should be cut for silage at the
stage of growth when the grain is glazed or dented. The grain
should be mature enough to pick for seed, and at this stage the
lower leaves of the stalk are beginning to turn brown.
Sorghum should reach about the same degree of maturity
as corn. That is, the seed should be quite mature and the bottom
leaves beginning to turn brown.
Japanese cane should be left growing until there is danger
of frost. Cane silage in the past has met with considerable dis-
satisfaction because of spoiling easily. This has been largely
due to immaturity and to improper packing in the silo. When
the cane is left growing until late in the fall and the silage
properly tamped in the silo, the results should be quite satis-
FILLING THE SILO
Filling the silo requires a great deal of labor and expensive
machinery. Farmers can cooperate to considerable advantage by
exchanging labor and buying jointly, a cutter, engine and corn
harvester. A corn harvester can be used to good advantage on
land free of stumps. This machine ties the corn in bundles,
making it possible to load up the wagons in the field and unload
at the cutter very quickly.
The wagons used should be low-down truck wagons equipped
with platform racks (racks without sides) and having upright
standards at both front and back ends. The bundles of corn
should be placed flat and crosswise of the wagon with the butts
all one way. Great care should be used in loading the wagons.
If the bundles are properly loaded they can be unloaded very
quickly; the cutter can be kept full and very little time will be
lost in waiting on the man ahead.
The harvester should be started a day or at least a half
day in advance of the filling, in order to keep enough corn cut
ahead of the wagons. This will depend upon the size of the
silo, the number of teams hauling and yield per acre. Cutting
down six acres with one binder is a good day's work. Ten men
22 Florida Cooperative Extension
with teams and hauling not more than a half mile and using
a fifteen inch cutter with a 20-horse gas engine, can fill a hundred
ton silo in ten hours. It is understood that the corn be tied in
bundles by the harvester and that the men be good workers and
on the job. In addition to the above, there should be two or
three men in the silo, one man to run the machinery and one man
to feed the cutter (a feeder is not required with some of the
One of the most important parts of the filling operation is
performed in the silo. It is very necessary to have two or three
good men in the silo to distribute the silage evenly and tamp
it down in order to exclude as much air as possible. Distribution
is greatly facilitated by the use of a jointed steel distributor
extending down into the silo 15 or 20 feet from the end of the
blower pipe. By tying a rope to the end of this distributor the
latter can be pulled around and the silage placed where desired
with very little labor. Many silos have been condemned and
some crops have been condemned for silage purposes because the
silage molded. The trouble in most cases was not that of the
silo nor the crops, but that of improper filling and especially
that part performed in the silo. The main thing is to exclude
the air by proper tamping and by sealing the doors tightly.
A good way to insure a tight fit at the door is to apply a
thick mud or cement paste around the door jam just before the
door is placed in position. Place only one door in at a time, and
as needed. It is dangerous to have the doors in above the heads
of the men in the silo doing the tamping, as there is sometimes
a poisonous gas present. Danger from this source will be avoided
if the doors are placed in position just as they are needed.
The shorter the fodder is cut the easier the air will be
excluded by tamping. It should not be cut in length to exceed
three fourths of an inch. This fineness or coarseness of cutting
can be regulated by changing the speed of the feed carrier and
by the number of knives on the cutter. A cutter with two knives
will cut coarser fodder than one with four knives run at the
same speed. The slower the cutter runs the coarser will be the
silage. Most people use only two knives but run the cutter fast
to get the desired length. This practice will take less power.
If the fodder is overripe and dry, water should be added to
the ensiled product. This can best be done by attaching a hose
from a water tank to the blower and blowing the water up with
The Silo in Florida 23
SEALING AND OPENING THE SILO
Sealing of the silo is not necessary, altho if some roughage
of less value than the silage material is available it would be
advisable. Under such conditions the roughage should be cut
in small pieces and then well wetted down. This can then be
improved upon by sowing some oats on top of the silage. The
oats will soon sprout and make a fibrous sod which will seal up
the silo very efficiently.
The silo may be opened any time after filling. It is not
necessary to wait until certain fermentation takes place. Begin
feeding the silage when needed.
Silage is a good feed for most all classes of stock, but is
more popular as a feed for cattle and sheep. Table 5 shows some
suggested rations in which silage furnishes the bulk of the
roughage. Rations for all classes with exception of ewes and
calves are based on thousand pound animals. Nearly every
ration has been tried out and has given good results. In this
table cottonseed meal, peanut meal and soy bean meal are given
in one column, and cold pressed cottonseed cake, velvet bean
meal and whole velvet beans in the pod in another column. These
feeds are divided in this way because those in each column are
similar in feeding quality and the amounts fed should be about
the same. Generally speaking, it will take about twice as much
cottonseed cake, whole beans or velvet bean meal to equal in
feeding value and produce as good gains as it will cottonseed,
peanut or soy bean meal.
In the feeding of cottonseed, peanut or soy bean meal the
former has proven to be the greatest source of protein, and in
most cases produces greater gains. Owing to the high cost of
cottonseed meal in later years, the greater gains produced have
been offset by greater cost of production and some of the other
feeds have netted the greatest profits. Peanut meal promises to
be a popular feed in the future. The analysis compares favorably
with cottonseed meal and can usually be bought at a less price.
Soy bean meal while not available in any large quantity is a
very nutritious and a very good feed.
24 Florida Cooperative Extension
TABLE 5.-Suggested Daily Rations in Which Silage Furnishes the
Bulk of the Roughage
Average daily ration for feeding period, in pounds
S I I? .. Ba
Class of stock '- W I
Fattening 150 4 8 5 8
bee animal 10 45 5to 10 to 12 2
Fattening 150 35 4 8 5 8
beef animal 150 45 5 to 6 10 to 12 2
120 35 4to5 8 to 10 5
90 35 5to6 10 to 12 10
Wintering 30 1 2 5
beef cow 40 1 2
25 1 5 10
Wintering 15 1 2 2% 5
beef calves 1 10 1 2 3 6
Fattening 25 3 6 4 ,6
baby beef 180 20 4 8 3 6
Dairy cow 40 5 10 2 4
Wintering 5 3
In the feeding of cold pressed cottonseed cake, velvet bean
meal and whole velvet beans with the pod, all have proven good
when fed in sufficient amounts. About two pounds of these
feeds are equivalent to one pound of cottonseed, peanut, or soy
bean meal. The cost of feed then should go far in determining
what feeds should be used in conjunction with the silage. Cold
pressed cottonseed cake has given very good results, but the
supply at present is limited. Whole velvet beans soaked have
given better results in steer feeding work than either whole
beans, dry, or velvet bean meal.
Silage fed alone is not a good feed for production, but
will do for a maintenance ration for wintering stock. Where
production is desired above maintenance, either in the form of
meat or milk, some concentrated feed high in protein must be
added. This can be supplied by the cottonseed, velvet bean or
soy bean products. In the foregoing rations the amount of silage
given is based on corn or sorghum silage. If Japanese cane
silage is used, more concentrated feed should be supplied to
make up for the grain and seed in the corn and sorghum silage.