Essentials for Development
=Sunlight.=--Abundant and unobstructed sunlight is the most essential
condition for the healthy growth of the tomato. It is a native of the
sunny South and will not thrive except in full and abundant sunlight. I
have never been able to grow good tomatoes in the shade even where it is
only partial. The entire plant needs the sunlight. The blossoms often
fail to set and the fruit is lacking in flavor because of shade, from
excessive leaf growth, or other obstruction.
The great difficulty in winter forcing tomatoes under glass in the North
comes from the want of sunlight during the short days of the winter
months. Were it not for the short winter days of the higher latitudes
limiting the hours of sunshine, tomatoes could be grown under glass in
the northern states to compete in price, when the better quality of
vine-ripened fruits is considered, with those from the Gulf states.
Growers are learning that tomatoes can be profitably grown under glass
during the longer spring days, and consumers are beginning to appreciate
the superior quality of fruit ripened on the vine over that picked green
and ripened in transit. At no time is this need of abundance of light of
greater importance than when the plants are young and, if they fail to
receive it, no subsequent favorable conditions will enable them to
recover fully from its ill effects. It is not so much the want of room
for the roots as of light for the leaves that makes the plants which
have been crowded in the seed-beds so weak and unprofitable.
I once divided 100 young tomato plants, about 2 inches high, into four
lots of 25 each, numbering them 1, 2, 3 and 4. The plants of lots No. 1
and 2 were set equal distance apart in box A, and those of lots No. 3
and 4 in the same way in box B; both boxes being about 16 inches wide,
40 inches long and 4 inches deep. The two boxes were set together across
the side bench of a greenhouse with the outer edge against a board wall
some 2-1/2 feet high, so that the plants at the end of the box near the
wall received much less light than those at the other end. They remained
there about five weeks and then were taken out and the plants set in the
open ground. During the five weeks box A, containing lots No. 1 and 2,
was changed, end for end, every day so that those two lots of plants
received nearly an equal amount of sunlight, but box B was not changed
so that lot No. 3, at one end of the box, was constantly near the walk
and in the full light, while lot No. 4, at the other end of the box, was
constantly near the wall and in partial shade. The effect on the growth
of the plants was very marked. The plants of lot No. 4 were nearly twice
as high, but with much softer stems and leaves than those of lot No. 3.
The plants received equal care when set side by side in the open ground
and at the time the first fruit was gathered seemed of equal size and
vigor, but the total yield of fruit of lots No. 1, 2 and 3 was very
nearly the same and in each case at the rate of over 100 bushels an acre
more than that from lot No. 4. This is but one of the scores of
experiences which have led me to appreciate, in some degree, the
necessity of plenty of sunlight for the best development of the tomato.
=Heat.=--The plant thrives best out of doors in a dry temperature of 75
to 85° F., or even up to 95° F., if the air is not too dry and is in
gentle circulation. The rate of growth diminishes as the temperature
falls below 75° until at 50° there is practically no growth; the plant
is simply living at a poor dying rate and if the growth, particularly in
young plants, is checked in this way for any considerable time they will
never produce a full crop of fruit, even if the plants reach full size
and are seemingly vigorous and healthy. The plant is generally killed by
exposure for even a short time to freezing temperature, though young
volunteer plants in the spring are frequently so hardened by exposure
that they will survive a frost that crusts the ground they stand in; but
such exposure affects the productiveness of the plant, even if it
subsequently makes a seemingly vigorous and healthy growth. Under glass,
plants usually do best in a temperature somewhat lower than is most
desirable out of doors. I think this is due to the inevitable
obstruction of the sunlight and the lack of perfect ventilation.
=Moisture.=--Although the tomato is not a desert plant and needs a
plentiful supply of water, it suffers far more frequently, particularly
when the plants are young, from an over-supply than from the want of
water. Good drainage at the root and warm, dry, sunny air, in gentle
motion, are what it delights in. Good drainage is essential not only to
the best growth of the plant but to the production of any fruit of good
quality. So important is this feature that though it can be readily
proved that, other things being equal, the tomato will give larger yield
and better fruit on well drained clay loam than on sandy soil, yet it is
more generally and more successfully planted on sandy lands simply
because they are usually better drained and on this account give better
crops. While excess of water in the soil is most injurious to the young
and growing plant, an abundance of it at the time the fruit swells and
ripens is very essential, and a want of it at that time results in small
and imperfect fruit of poor flavor. Excessive moisture in the air is
just as injurious as at the root. In my personal experience I have known
of more failures in tomato crops, at least in the northern states, to
come from a season of persistent rains and damp atmosphere at the time
when the plants should be in bloom and setting fruit than from any other
climatic cause.
=Food supply.=--The tomato is not a gross feeder nor is the crop an
exhaustive one, but the plant is very particular as to its food supply.
It is an epicure among plants and demands that its food shall not only
be to its taste in quality but that it be well served. In order for the
plant to do its best, or even well, it is essential that the food
elements be in the right proportions and readily available. If there is
a deficiency of any single element there will be but a meager crop of
fruit, no matter how abundant the supply of the others. An over-supply
of an element, especially nitrogen, is hardly less injurious and will
actually lessen the yield of fruit though it may increase the size of
the vine. Not only must the food be in right proportions but in such
condition as to be readily available. Tomato roots have little power to
wrest plant food from the soil. The use of coarse, unfermented manure is
even more unsatisfactory with this than with other crops. The enormous
yields sometimes obtained by English gardeners from plants grown under
glass result from a supply of food of the right proportions and in
solution, instead of incorporating it in a crude condition with the
soil.
=Cultivation.=--The tomato is grown in all parts of the United States
and under very different conditions, not only as to climate and soil but
as to the facilities for growing and handling the crop and the way in
which it is done. What would be ideal conditions of soil and the most
advantageous methods under some conditions would not be at all desirable
in others. In some cases the largest possible yield an acre, in others
fruit at the lowest cost a bushel, or at the earliest possible date, or
in a continuous supply and of the best quality, is the greatest
desideratum. It is impossible to give specific instructions which would
be applicable to all these varying conditions and requirements; so I
give general cultural directions for maximum crops with variations
suggested for special conditions and requirements, and then the reader
may follow those which seem best suited to his individual conditions.