General Characteristics of the Plant
=In the native home= of the tomato, in South America, the conditions of
the soil, both as regards composition and mechanical condition, of the
moisture both in soil and air, and those of temperature and sunlight,
are throughout the growing season not only very favorable for rapid
growth, but are uniformly and constantly so. Under such conditions there
has been developed a plant which, while vigorous, tenacious of life,
capable of rapid growth and enormously productive, is not at all hardy
in the sense of ability to endure untoward conditions either in the
character of soil, of water supply, or of temperature. A check in the
development because of any unfavorable condition is never fully
recovered from, but will inevitably affect the total quantity and
quality of the fruit produced, even if subsequent favorable conditions
result in the rapid and vigorous growth of the plant.
I know of an instance where two adjoining fields belonging to A and B
were set with tomatoes, using plants started in the same hotbed from the
same lot of seed. The soil was of equal natural fertility and each field
received about the same quantity of manure, though that given A's was
all well decomposed and worked into the soil, while that given B's was
fresh and raw and simply plowed in. A's field was put into the best
possible tilth before setting the plants, and the management of the
plants and their cultivation were such as to secure unchecked growth
from the time they were pricked out into cold-frames and set in the
field until the crop was matured. As long as the plants would permit,
the soil was cultivated every few days and kept in a state of perfect
tilth.
B's field when the plants were set out was a mass of clods, as it had
been plowed, when wet, some time before and never harrowed but once.
The plants had been crowded forward as rapidly as possible in the
cold-frame, and when set in the field were much higher than A's, but so
soft that they were badly checked in transplanting and a great many of
them died and had to be reset. The field received but one or two
cultivations during the entire season. The growth of the plants in B's
field was irregular and uneven instead of steady and uniform as in A's,
and though some of the fruits were quite as large, they were not as
uniform as A's while the yield per acre was not more than half as much
nor the fruit of as good general quality. B had difficulty in disposing
of his crop and often had to sell below the market, while A had no
trouble in disposing of his at the highest prices for the day. B's crop
was a financial loss, while A's returned a most satisfactory profit.
The key to the most successful culture of the tomato is the securing,
from the start to finish, of an unchecked uniform growth, though it need
not necessarily be a rapid one. The failure to do this is, in my
opinion, the principal reason for the comparatively small yield usually
obtained, which is very much less than it would be with better cultural
management. The tomato under conditions which I have repeatedly found it
practicable to secure, not only in small plantings but in large fields,
has proved capable of producing from 1,000 to 1,200 or even more bushels
to the acre, and the possible yield per plant is enormous.
As early as 1818 the Royal Horticultural Society of London reports the
obtaining of over 40 pounds of fruit of marketable character from a
single vine. An acre of such plants would give a yield of over 1,800
bushels of fruit, and many similar yields, and even greater ones, have
been recorded for single plants. The yield commonly obtained, even in
favorable locations, and by men who have grown tomatoes all their lives,
is more often less than 200 bushels to the acre than more. The way to
secure a better yield is to study carefully the nature and requirements
of the plants and the adaptation of our cultural practice to them.
=Life habit of the plant.=--The tomato could be described as a
short-lived perennial, but its span of life is somewhat variable. Under
favorable conditions it will develop from starting seed to first ripe
fruit in from 85 to 120 days of full sunshine with a constant day
temperature of from 75 to 90° F., and with one from 15 to 20° F. lower
at night. The plants will ordinarily continue in full fruit for about 50
to 60 days, after which they generally become so exhausted by excessive
production of fruit and the effects of diseases to which they are
usually subject that their root action and sap circulation become weaker
and weaker until they die from starvation. From Philadelphia southward
gardeners expect that spring set plants will thus exhaust themselves and
die by late summer, and they sow seed in late spring or early summer for
plants on which they depend for late summer and fall crops.
Under some conditions, particularly in the Gulf states and in
California, tomato plants will not only grow to a much greater size than
normal, but will continue to thrive and bear fruit for a longer time.
Such a plant grown in Pasadena, Cal., was said to have been in constant
bearing for over 10 months. Again, sometimes plants that have produced a
full crop of fruits will start new sets of roots and leaves and produce
a second and even a third crop, each, however, being produced on new
branches and as a result of a fresh set of roots, those which produced
the preceding crop having died and disappeared. The period of
development, 85 to 120 days of full sunshine at a temperature above 75°
F., has been given. The full sunshine and high temperature are essential
to such rapid development, and in so far as there is a lack of sunshine
from clouds or shade, or the day temperature falls below 75° F. the
period will be lengthened, so that in the greater part of the United
States the elapsed time between starting seed to ripened fruit is
usually as much as from 120 to 150 days and often even longer.
=Characteristics of the root.=--The roots of the tomato plant, while
abundant in number, are short and can only gather food and water from a
limited area. A plant of garden bean, for instance, is not more than
half the size of one of the tomato, but its roots extend through the
soil to a greater distance, gather plant food from a greater bulk of
soil, seem better able to search out and gather the particular food
element which the plant needs than do those of the tomato. This
characteristic of the latter plant makes the composition of the soil as
to the proportion of easily available food elements of great importance.
Tomato roots are also exceedingly tender and incapable of penetrating a
hard and compact soil, so that the condition of the soil as to tilth is
of greater importance with regard to tomatoes than with most garden
vegetables.
Another characteristic of the tomato roots is that the period of their
active life is short. When young they are capable of transmitting water
and nutritive material very rapidly, but they soon become clogged and
inefficient to such an extent as to result in the starvation and death
of the plant. If the branches of such an exhausted plant be bent over
and covered with earth they will frequently start new roots and produce
a fresh crop of fruit, or if plants which have made a crop in the
greenhouse be transplanted to the garden and cut back, a new set of
roots will often develop and the plant will produce a second crop of
fruit which, in amount, often equals or exceeds the first one. But such
growths come only from new roots springing from the stem--never from an
extension of the old root system.
=Characteristics of the stem and leaves.=--The growth of the stem, and
leaves of the young tomato plant is very rapid and, the cellular
structure coarse, loose and open. A young branch is easily broken and
when this is done it shows scarcely any fibrous structure--simply a mass
of coarse cellular matter which while capable, when young, of
transmitting nutritive matter rapidly, soon becomes dogged and inert.
This structure not only makes the active life of the leaves short, like
that of the roots, but necessitates a fresh growth in order to continue
the fruitfulness of the plant and renders the leaves very susceptible to
injury from bacterial and fungous diseases. The rapid growth also
necessitates an abundance of sunlight.
=Characteristics of the blossom.=--The inflorescence of the tomato is
usually abundant and it is rare that a plant does not produce sufficient
blooms for a full crop. The flowers are perfect as far as parts are
concerned (Fig. 2) and in bright, sunny weather there is an abundance of
pollen, but sunlight and warmth are essential to its maturing into a
condition in which it can easily reach the stigma. The structure and
development of the flower are such that while occasionally, particularly
in healthy plants out of doors, the stigma becomes receptive and takes
the pollen as it is pushed out through the stamen tube by the elongating
style, it is more often pushed beyond them before the pollen matures, so
that the pollen has to reach the stigma through some other means.
Usually this is accomplished by the wind, either directly or through the
motion of the plants.
Under glass it is generally necessary to assist the fertilization either
directly by application or by motion of the plant, this latter only
being effective in the middle of a bright sunny day. In the open ground
in cold, damp weather the flowers often fail of fertilization, in which
case they drop, and this is often the first indication of a failing of
the crop on large, strong vines. I have known of many cases where the
yield of fruit from large and seemingly very healthy vines was very
light because continual rains prevented the pollenization of the
flowers. Such failures, however, do not always come from a want of
pollen but may result from an over or irregular supply of water either
at the root or in the air, imperfectly balanced food supply, a sapping
of the vitality of the plants when young, or from other causes. Insects
rarely visit tomato flowers and are seldom the means of their
fertilization.
=Characteristics of the fruit.=--The fruit of the original species from
which our cultivated tomatoes have developed was doubtless a
comparatively small two to many-celled berry, with comparatively dry
central placenta and thin walls. In some species the cells were
indicated by distinct sutures, forming a rough or corrugated fruit. It
has improved under cultivation by increase in size, the material
thickening of the cell walls, the development of greater juiciness and
richer flavor and a decrease in the size and dryness of the placenta, as
well as the breaking up of the cells by fleshy partitions resulting in
the disappearance of the deep sutures and an improvement in the
smoothness and beauty of the fruit. (Fig. 11.)
The quality of the fruit is largely dependent upon varietal differences,
to be spoken of later, but it is also influenced by conditions of
growth--such as the proportion of the nutritive elements found in the
soil, the proper supply of moisture, the degree and uniformity of
temperature and, most of all, the amount of sunlight. Sudden changes of
temperature and moisture often result in cracks and fissures in the skin
and flesh, which not only injure the appearance but affect the flavor of
the fruit.
[Illustration: FIG. 11--TYPICAL BUNCH OF MODERN TOMATOES Contrast with
Figs. 9 and 10]