MANURES AND FERTILIZERS

To a very small extent garden vegetables get their food from the air.
The amount obtained in this way however, is so infinitesimal that from
the practical standpoint it need not be considered at all. Practically
speaking, your vegetables must get all their food from the garden soil.
This important garden fact may seem self-evident, but, if one may judge
by their practice, amateur gardeners very frequently fail to realize
it. The professional gardener must come to realize it for the simple
reason that if he does not he will go out of business. Without an
abundant supply of suitable food it is just as impossible to grow good
vegetables as it would be to train a winning football team on a diet of
sweet cider and angel cake. Without plenty of plant food, all the care,
coddling, coaxing, cultivating, spraying and worrying you may give will
avail little. The soil must be rich or the garden will be poor.
Plant food is of as many kinds, or, more accurately speaking, in as
many _forms_, as is food for human beings. But the first
distinction to make in plant foods is that between available and non-
available foods--that is, between foods which it is possible for the
plant to use, and those which must undergo a change of some sort before
the plant can take them up, assimilate them, and turn them into a
healthy growth of foliage, fruit or root. It is just as readily
possible for a plant to starve in a soil abounding in plant food, if
that food is not available, as it would be for you to go unnourished in
the midst of soups and tender meats if the latter were frozen solid.
Plants take all their nourishment in the form of soups, and very weak
ones at that. Plant food to be available must be soluble to the action
of the feeding root tubes; and unless it is available it might, as far
as the present benefiting of your garden is concerned, just as well not
be there at all. Plants take up their food through innumerable and
microscopic feeding rootlets, which possess the power of absorbing
moisture, and furnishing it, distributed by the plant juices, or sap,
to stem, branch, leaf, flower and fruit. There is one startling fact
which may help to fix these things in your memory: it takes from 300 to
500 pounds of water to furnish food for the building of one pound of
dry plant matter. You can see why plant food is not of much use unless
it is available; and it is not available unless it is soluble.