AGRICULTURAL EXTENSION SERVICE
Circular 127 February 1955
JASPER N. JOINER
T. J. SHEEHAN
Assistant Ornamental Horticulturist
Mist propagation is a system of rooting cuttings by keeping
them constantly moistened with a fine mist-spray of water. Origi-
nally it was called constant mist, since it was believed necessary
to keep cuttings bathed in mist during the entire rooting period.
Later research work has shown that a constant mist is not
necessary-the important factor is to keep the cuttings moist.
Cutting material continues to lose water by transpiration after
it is severed from the parent plant. It is impossible for the cut-
tings to take up sufficient water to replace that lost by very
rapid transpiration until new roots are formed. The mist sys-
tem prevents excessive loss of water by the cutting material.
Maintaining a high water level in the cuttings helps more
plants to root and speeds up the rooting process. In addition,
the mist system eliminates most insect and disease problems in
cutting beds, making it possible to root material in unsterilized
media. The mist system reduces labor costs by eliminating
many disease and insect control measures and the necessity of
Although there are many advantages to the mist method, it
must not be considered a cure-all in plant propagation. Some
plants, such as the crown of thorns (Euphorbia mili), some spe-
cies of Begonia and a few others, both herbaceous and woody,
have not yet been successfully rooted by this method.
The average homeowner who propagates only a relatively
few cuttings should turn the mist on about 8 a.m. and leave it
on constantly until about 5 p.m. Since each nozzle is designed
to cover an area of about four square feet, one is usually suffi-
cient for the home gardener. The atomizing mist nozzles use
about one and one-half gallons of water per hour. It is not neces-
sary to keep the mist running all night.
Commercial propagators will probably find it economically
feasible to use time clock devices to create an interrupted mist
system. Where time clocks are used, they can be set for different
intervals. The most desirable interval will depend on the ma-
terial being propagated, relative humidity, temperature and
other factors. Experimental evidence indicates that one of the
best starting cycles is 15 seconds on and 45 seconds off, with
a hardening off cycle of 5 seconds on and 55 seconds off.
Part of the problem of mist interval is being solved with an
electronic leaf solenoid which automatically turns the mist off
when leaves of cutting material are damp and turns the mist on
as soon as the leaves dry off. This is a relatively inexpensive
device which automatically compensates for most weather con-
ditions. As stated before, the important thing is not to allow
the cuttings to dry out between mistings.
The amount of water saved by interrupted misting is often
enough to pay for the devices necessary to set up such a system
in a large operation.
Some researchers currently believe it best to keep the mist
running 24 hours per day-whether constant or interrupted-to
prevent diseases in the propagating area. Others believe that
misting during daylight hours only is sufficient to prevent dis-
eases and give all the other benefits of the mist system.
In areas of high winds-such as the coastal areas-cuttings
will often wilt at night without the mist unless they are pro-
tected from the drying winds with cheesecloth or similar ma-
Fig. 1.-Left, commercial type mist propagator. Right, home garden
Complete success has been obtained using nothing but chicken
wire as a medium. Any material that will hold the cuttings in
an upright position can be used and many plant materials will
root in the air as long as they are kept moist.
Types of Cuttings
One of the major advantages of mist propagation is that cut-
tings too large to root satisfactorily by conventional methods will
root readily under this system. By rooting larger cuttings it is
possible to gain considerable time in getting material of large
size. Many ordinarily hard-to-root materials very often root
more easily under mist. For example, rose and chrysanthemum
cuttings 14 inches long have rooted very readily under mist.
Most plants that can be propagated by softwood cuttings-such
as broad-leaved evergreens-roots without difficulty under mist.
Cuttings of this type four inches or more in length are usually
taken during summer months, about three to four weeks after
a growth cycle is completed. Each cutting should have at least
three or four sets of leaves. The lower leaf or pair of leaves is
removed and the cutting is placed in the rooting material. The
more leaves left on the cutting the better. The larger the leaf
surface present the more chance the cutting will have to manu-
facture food which will make it root more rapidly.
Leaf bud cuttings can be used to propagate hydrangea, ficus,
philodendron and crotons. A leaf with its axiliary bud is cut
from the parent plant. Usually a small section of the twig, about
1/2 inch above and below the point of leaf attachment, is removed
with the leaf. The separated section is treated in the same
manner as a tip cutting, except that the bud should be covered
with the rooting material.
Leaf cuttings are made by taking the leaf blade and petiole
from the parent plant. The leaf petiole is then inserted into the
medium to a depth of % inch. It is important that all cuttings
be made with a sharp knife.
Cuttings should be placed in the medium from 1 to 11/ inches
deep. It is necessary to plant them only deep enough to have
them remain in an upright position. The deeper the cuttings
are planted the longer it will take for them to root, due to dif-
ferences in amount of air at different soil depths.
Regardless of type of cutting, the time required for rooting
will vary considerably with the plant material used.
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
H. G. Clayton, Director
trial. In excessively dry, windy weather, a mist during eve-
ning hours might be desirable.
Placement of Mist Propagating Beds
Mist propagators may be placed in full sunlight, since high
light intensity helps to maintain a disease-free condition in the
cutting beds. In addition, direct sunlight speeds up the life
processes in cuttings, thereby increasing frequency and speed of
Some cuttings under mist in full sunlight turn a bright yellow
or purple while rooting. For these it is desirable to place the
mist propagators under partial shade. Although partial shade
will have a tendency to slow down rooting processes it will aid
in maintaining the normal green coloration of cuttings which, in
turn, will increase their food manufacturing ability.
Due to drainage factors, it is necessary that all benches used
for mist propagation be elevated at least 8 inches above the
Various media have been tested and a combination of coarse
sand and peat-equal parts by volume-appears to be a good
one. Other materials, of course, can be used. Some of these
include vermiculite, fine gravel of poultry cut size, pure sand
(coarse), and sawdust. Most of these materials can be used in
combination, with the exception of vermiculite and sawdust.
Experiments have shown that at times these two materials in
combination do not drain properly and cause severe loss of cut-
For several reasons it is important that the media-regardless
of type used-be between 3 and 4 inches deep and no deeper.
First, since drainage under mist is often a problem, the more
shallow the rooting medium the less trouble with drainage. Sec-
ond, a shallow rooting medium is ideal to provide sufficient oxy-
gen to the rooting area of the cutting.
Fig. 2.-Left, leaf cutting; center, leaf bud; right, herbaceous cutting.