Sphagnum Moss for Seed Germination 
Sphagnum may be used in coldframes or 
in containers with pervious bottoms. In the 
ordinary flats the moss may constitute the 
whole filling, but if the supply is limited it 
may be used as a layer an inch thick over a 
foundation of soil, sand, or sand and peat, 
providing the foundation drains reasonably 
well. Old wooden flats showing evidence 
of wood-rooting fungi should be rejected, as 
some of these fungi decompose the spkag- 
num. 
The moss is moistened slightly and the flat 
is filled level; then the surface is firmed un- 
til it is a half inch below the rim wf the flat. 
It is then watered thoroughly and allowed to 
stand for a few minutes. Since the smooth 
compact surface is favorable to the growth 
of green algae, an additional layer of sphag- 
num one-eight of an inch thick is applied and 
given a light sprinkling. 
Sowing the Seeds 
Seeds are then sown broadcast or in rows. 
If several varieties are to be broadcast in the 
same flat, they can be seperated by a thin line 
of dry sand; this does not disturb the sphag- 
num, as would the insertion of wooden strips 
or other markers. Usually no covering is 
given the seed, though a light covering of the 
larger kinds does no harm. When the seed 
has been sown, the surface is given a very 
light sprinkling, a mist from an atomizer is 
best, and is then covered with a pane of giass. 
This may rest on a light wooden frame that 
fits exactly on the rim of the flat and raises 
the glass an inch. Tacking one of the glass 
substitutes on these frames is convenient in 
obviating the weight and awkwardness of 
glass. Both light-sensitative and light-inhib- 
ited seeds have germinated well in the subdued 
light under translucent glass substitutes. 
The flats are not exposed to strong sunlight 
while covered with close-fitting transparent 
covers. With the frame cover applied, no fur- 
ther attention is needed for 2 or 3 weeks in 
a greenhouse atmosphere, a period ample for 
the germination of many seeds. Ordinarily 
no additional watering is needed during this 
period, but in a dryer atmosphere it may be 
required several times before germiaation. 
In case of doubt, however, water may be ap- 
plied, as it does no harm. 
When germination is complete the frames 
are removed. From this time care must be 
taken against drying out, which may osvur 
before the condition is noticed. Fortunately, 
however, this is a much simpler matter with 
sphagnum than with soil, because sphagnum 
tolerates overwatering and in case of doubt 
water can and should be applied, whereas with 
soil excessive watering is as disastrous as in- 
sufficent watering. 
The acidic reaction (about pH4.3) of ihe 
sphagnum might cause some doubt as to the 
suitability of the material for seeding certain 
plants. For instance, cacti and succulents 
are often sown in a compost containing lime 
sufficient to produce a neutral or even slight- 
ly alkaline reaction. Seeds of these plants, 
however, germinate well in sphagnum and 
grow for long periods if supplied nutrient sol- 
utions occasionally. Addition of lime to the 
sphagnum has been detrimental rather than 
advantageous. 
Use of nutrient solutions 
During the period of hardening following 
the removel of the pane of glass, fine metal 
screen or thin cheesecloth in light wooden 
frames is useful for covering the flats, as it 
reduces the rapidity of surface drying and 
protects the seedlings from attacts by rodents 
The foilowing article is part of a leaflet 
of the U. S. Dept. of Agriculture 
or roaches. 
Although satisfactory plants for early trans- 
planting may be grown without the use of 
mineral nutriments, somewhat more vigorous 
growth may be obtained if a minerei nutri- 
ent solution is applied to the sphagnum be- 
fore the seeds are sown or after they have 
germinated. The composition of the nutri- 
ent solutions for use with young seellings ap- 
parently may vary widely, and various sol- 
utions have been tried with excellent results. 
A useful solution may be made by stirring | 
teaspoonfull each of potassium nitrate (salt- 
peter) and superphosphate in a gallon of wat- 
er and applying a quantity sufficient to satur- 
ate the moss. A solution containing 2 te2- 
spoonfuls of a 12-12-6 fertilizer mixture per 
gallon has often been used at the Plant Iniro- 
duction Garden. A satisfactory solution may 
also be made by stirring 5 to 6 teaspoonstfuls 
of one of the less concentrated complete 
garden fertilizers, as a 4-12-4 or a 5-8-6 mixt- 
ure, in a gallon of water. The insoluaole re- 
sidue that may be expected with these feruliz- 
ers should be discarded. Nutrient solutions 
applied at intervals promote a steady growth 
of the seedlings and normally are recom- 
mended if the seedlings are to be left in 
sphagnum beyond the cotyledon stage. 
Retention of seedlings in sphagnum 
Withholding nutrients from the sphagnum 
soon checks the growth of the seedlings and 
keeps them in an arrested state of develop- 
ment without loss or deterioration, in some 
cases for a long time. Normal growth may 
be induced at any time by transplanting out 
of the flat. This is a very great advantage 
over soil, in which ordinarily the plants can- 
not be retained without serious difficulties. 
Seedlings of Cinchona (quinine tree) kept for 
a year in the seed flat have begun growth in 
normal condition upon application of a nut- 
rient solution. Extra plants of some species 
can thus be held back in a seed flat for an 
indefinite period as a reserve. This feature 
of germination on sphagnum should be use- 
ful also in commercial establishments where 
space is limited and may not be available at 
the proper time for transplanting. With 
many species one sowing can supply a success- 
ion of transplants for an entire season. Fur- 
ther experimentation, however, is needed to 
determine the applicability to various species 
of plents. Another promising feature of the 
use of sphagnum is that seeds that are too 
short-lived for successful storage can be germ- 
inated and the seedlings held in a retarded 
condition until desired. 
Control of damping-off 
The freedom of seedlings from loss by at- 
tacts of damping-off is remarkable if sphag- 
num is used in accordance with the above in- 
structions. The acid reaction of the sphag- 
num may be a factor in its control, but it does 
not explain the results, as severe damping- 
off has often been found under identical con- 
ditions with soil mixtures having the same re- 
action. The use of sphagnum dispenses with 
any need for various methods of sterilizing 
the seedling medium. In no case has chem- 
ical treatment of seed for dainping-oif contiol 
been practiced. For the gardener or the 
small commercial grower this does away with 
the hazards of indiscriminate use of chemi- 
cals. Where needed, however, treatments for 
seed-borne diseases, as distinguished from 
damping-off, should be used. 
Seedlings of tomato, pepper, petunia, snap- 
dragon, cardinalflower, and scarlet sage were 
germinated on sphagnum and in soil. Inoc- 
ulations with damping-off fungi, including sev- 
eral kinds, were made singly on the plots. On 
sphagnum a very few seedlings were vltacied 
at the points of inoculation, but in no instance 
did the infection spread. In soil most of the 
seedlings died. When flats were so prepared 
that the soil plots adjoined sphagnum picts 
with no barriers between them, seedlings on 
sphagnum were uninjured, but on the adjoin- 
ing soil few escaped. 
Transplanting 
In many cases seedlings are pricked off 
from the flats at an early stage, sometimes 
after only two weeks, but the time for trans- 
planting is not at all critical unless the seedl- 
ings are overcrowded. Removal from sphag- 
num ordinarily causes less disturbance to the 
root systems than is usual when they are 
transplanted from soil. The frames covered 
with wire screen or cheesecloth, often used 
during the period of hardening-off of seed- 
ling, are likewise useful for covering flats into 
which seedlings have been recently transplant- 
ed. 
Growing and shipping plants 
Excellent growth for an indefmite period 
has been obtained with plants transplanted in 
sphagnum and watered occasionally with nu- 
trient solutions. The use of sphagnum is ad- 
vantageous for growing plants that are to te 
shipped, because of the light weight of the 
moss in comparison with soil. It has recent'y 
been used extensively for growing plants to be 
transported by airplane. Plants grown for 
shipment may be lifted and separated with- 
out serious damage to the roots if they have 
not been standing in sphagnum for an unduly 
long period. Plants may be grown in pots of 
sphagnum and knocked out for shipmeni; tne 
balls of sphagnum do not scatter as do balls 
of soil. 
Plants grown in sphagnum do not appear 
to have any important disadvantages in vom- 
parison with those started in soil when hued 
out under ordinary garden or nursery con- 
ditions in the Temperate Zone. Experiments 
on several types of soils with a variety of veg- 
etable plants and also several woody orna- 
mentals have shown few differences in growth 
between the plants grown in sphagnum end 
those grown in soil prior to lining-out. Care 
should always be taken to place soil over any 
sphagnum that may adhere to the roots. 
(NOTE: We have a good supply of mill- 
ed sphagnum made up this year but due to the 
extremely wet season and the labor shortage, 
not as much was gotten in as we wished, 
thus it will be best to order as early as poss- 
le. See under supplies on page 16. 
I e o 
ris pumila 
Iris pumila is a dwarf 4-8 inch Iris and 
it always grows with us to be at least 12 
inches high. We have secured plants from 
many different sources both here andin 
Europe, and always with the same results, 
plants that grow a foot or more tall. 
I now come to the conclusion that if one 
really wants an 4-8 inch purnila, it will be 
necessary to grow it as it is found in its 
native locations, viz., on dry stoney hills. 
Our soil is rich and not in any way like 
a dry stoney hill. You Iris fans who have 
been tring to BUY a dwarf pumila had 
better try them on some poor soil! 
