Bacteria as the Gardener’s Allies 
THE THEORY AND PRACTICE OF INOCULATING SEED OF THE POD-BEARING 
PLANT WITH BACTERIA THAT HELP THEM TO DRAW NITROGEN FROM THE AIR 
by Katharine Newbold B i r d s a l l 
T HE home gardener, as well as the farmer, has cause to thank 
the scientists who have been experimenting with the ques¬ 
tion of fertilizing seeds before planting, as against the old method 
of fertilizing the soil in which the seeds are sown. Is it not a sim¬ 
ple matter to buy one’s fertilizer in a small bottle in the form of 
jelly, add a little sugar and water, shake the bottle thoroughly to 
dissolve the jelly, and pour the liquid into a bowl in which the 
seeds have previously been placed? The seeds need only to be 
moistened with this solution, which contains a certain bacteria, to 
inoculate them with the power to form nodules on their roots 
which absorb nitrogen from the air and feed it to the plants. 
Surely this is a much more simple process than the purchase of 
fertilizers which must be worked into the ground. The one draw¬ 
back to this great scheme is that it directly benefits only the 
legumes — the pod-bearing plants such as peas, beans, sweet peas, 
alfalfa, peanuts, etc. Indirectly, however, it benefits other crops 
as well, for while these do not form nodules on their roots they 
seem to thrive better in soil that has grown inoculated legumes. 
A bacterium, the scientists tell us, is “the smallest of the micro¬ 
scopic organisms” — the smallest of the vegetable organisms, com¬ 
posed of but a single cell, which can move and propagate itself. 
The work of the beneficial bacteria, which interest us for our 
gardens, is that of supplying to certain plants the most necessary 
element of plant life, nitrogen. Nitrogen, as many of us have 
learned, is one of the essential constituent parts of the elementary 
material which composes plant and animal life. It is a neces¬ 
sary ingredient in foods for animal and for plant life. Most 
plants absorb it through the soil and furnish it in food for animals. 
When living things die or secretions decompose, some of their 
nitrogen, largely in the form of ammonia, is reduced to nitrates by 
bacteria and is then food for plants. Hence we fertilize our soil 
with decomposed matter in order to enrich it with nitrogen which 
shall be absorbed 
by the seeds and 
roots. 
One function of 
certain bacteria is 
to decompose sub¬ 
stances which, if 
allowed to collect, 
would fill the whole 
earth with dead 
animals and plants. 
If it were not for 
these bacteria, dead 
animal and plant 
bodies would re- 
m a i n as fixed as 
rocks; dead trees, 
plants, animal and 
human bodies 
would cover every¬ 
thing. Nature has 
provided bacteria 
to decompose these 
bodies as soon as 
life ceases, resolv¬ 
ing them into their 
original simple 
Root of a pea vine showing the nodules in¬ 
strumental in extracting nitrogen from the 
air 
chemical elements. This decomposition is prevented by man when 
he quiets the bacteria bv preserving meats and vegetables. Ice 
also quiets the bacteria for they must have comparative warmth 
to become active and to grow. 
There is plenty of nitrogen in the atmosphere for all animals 
and plants. The question is, how shall we get it? Man absorbs 
it in certain foods. Foods absorb it through fertilizers. The 
population of the earth is fast increasing; the supply of fertiliz¬ 
ers is not increasing and is insufficient for the foodstuffs. 
As the atmosphere is four-fifths nitrogen, it stands to reason 
for economy that we should get our nitrogen fertilizer direct from 
the air. It is an elusive element, but the scientists have caught or 
“fixed” it by a simple process, with the aid of nature. They en¬ 
courage the plants themselves to do the work of gathering the 
bacteria, which in turn help the plant to gather nitrogen from the 
atmosphere, and store it for plant use. 
Bacteria are much too small to be seen by the naked eye. A pin 
head will hold thousands of them. There is no way exactly to 
count them, and they multiply with marvelous rapidity. Each 
bacterium will divide itself and then divide again and again into 
myriads of new bacteria; this process is called “fission.” 
The certain plants upon which nitrogen-gathering bacteria 
thrive are legumes, comprising most of the pod-bearing plants. 
The method of securing the bacteria for farm and garden use has 
recently been perfected and is now within the reach of everyone— 
a wonderful piece of work when we consider that there are thou¬ 
sands of different kinds of bacteria in the soil, and unless we have 
the righ kind for the crop we wish to plant, they will do no good. 
Each kind of legume has its own particular kind of bacteria. 
The bacteria settle in groups on the rootlets of most pod-bearing 
plants, peas, beans, lentds, clover, etc. They can easily be seen by 
the naked eye when grouped in colonies in little knots or lumps 
called “nodules” 
which grow on the 
rootlets of the 
healthy plants. 
These bacteria are 
nitrogen - gathering 
and have a store of 
nutriment to feed 
to the plants. This 
being established as 
a fact, scientists 
had but to gather 
the bacteria and in¬ 
oculate other plants 
with them, so that 
new nodules form 
on the plants, and 
the bacteria which 
increase so rapid¬ 
ly gather nitrogen 
for the new plant. 
The next import¬ 
ant question was to 
supply them to the 
farmers and gar- 
(Confirmed on 
Page 373) 
At the left a vine grown from inoculated 
seed showing the comparison with the 
ordinary kind 
(354) 
