Seed Purity And Vitality





Seeds produce plants. The difference between a large and a small yield

may depend upon the kind of plants we raise, and the kind of plant in

turn is dependent upon the seeds that we sow.



Two things are important in the selection of seeds--purity and vitality.

Seeds should be _pure_; that is, when sown they should produce no other

plant than the one that we wish to raise. They should be able to grow.

The ability of a seed to grow is termed its _vitality_. Good seed should

be nearly or quite pure and should possess high vitality. The vitality

of seeds is expressed as a per cent; for example, if 97 seeds out of 100

germinate, or sprout, the vitality is said to be 97. The older the seed

the less is its vitality, except in a few rare instances in which seeds

cannot germinate under two or three years.



Cucumber seeds may show 90 per cent vitality when they are one year old,

75 per cent when two years old, and 70 per cent when three years

old--the per cent of vitality diminishing with increase of years. The

average length of life of the seeds of cultivated plants is short: for

example, the tomato lives four years; corn, two years; the onion, two

years; the radish, five years. The cucumber seed may retain life after

ten years; but the seeds of this plant too lose their vitality with an

increase in years.



It is important when buying seeds to test them for purity and vitality.

Dealers who are not honest often sell old seeds, although they know that

seeds decrease in value with age. Sometimes, however, to cloak

dishonesty they mix some new seeds with the old, or bleach old and

yellow seeds in order to make them resemble fresh ones.



It is important, therefore, that all seeds bought of dealers should be

thoroughly examined and tested; for if they do not grow, we not only pay

for that which is useless but we are also in great danger of producing

so few plants in our fields that we shall not get full use of the land,

and thus we may suffer a more serious loss than merely paying for a few

dead seeds. It will therefore be both interesting and profitable to

learn how to test the vitality of seeds.



To test vitality plant one hundred seeds in a pot of earth or in damp

sand, or place them between moist pieces of flannel, and take care to

keep them moist and warm. Count those that germinate and thus determine

the percentage of vitality. Germinating between flannel is much quicker

than planting in earth. Care should be used to keep mice away from

germinating seeds. (See Fig. 61.)




Consisting of two soup plates, some sand, and a piece of cloth]



Sometimes the appearance of a package will show whether the seed has

been kept in stock a long time. It is, however, much more difficult to

find out whether the seeds are pure. You can of course easily

distinguish seeds that differ much from those you wish to plant, but

often certain weed seeds are so nearly like certain crop seeds as not to

be easily recognized by the eye. Thus the dodder or "love vine," which

so often ruins the clover crop, has seeds closely resembling clover

seeds. The chess, or cheat, has seeds so nearly like oats that only a

close observer can tell them apart. However, if you watch the seeds that

you buy, and study the appearance of crop seeds, you may become expert

in recognizing those that have no place in your planting.



One case is reported in which a seed-dealer intentionally allowed an

impurity of 30 per cent to remain in the crop seeds, and this impurity

was mainly of weed seeds. There were 450,000 of one kind and 288,000 of

another in each pound of seed. Think of planting weeds at that rate!

Sometimes three fourths of the seeds you buy are weed seeds.



In purchasing seeds the only safe plan is to buy of dealers whose

reputation can be relied upon.



It not seldom happens that seeds, like corn, are stored in open cribs or

barns before the moisture is entirely dried out of the seeds. Such seeds

are liable to be frozen during a severe winter, and of course if this

happens they will not sprout the following spring. The only way to tell

whether such seeds have been killed is to test samples of them for

vitality. Testing is easy; replanting is costly and often results in a

short crop.




Tube 1 represents one pound of redtop grass as bought; Tube 2, amount of

pure redtop grass seeds in Tube 1; Tube 3, amount of chaff and dirt in

Tube 1; Tube 4, amount of weed seeds in Tube 1; Tube 5, amount of total

waste in Tube 1; Tube 6, amount of pure germinable seeds in Tube 1]



=EXERCISE=



Examine seeds both for vitality and purity. Write for farmers'

bulletins on both these subjects. What would be the loss to a

farmer who planted a ten-acre clover field with seeds that were 80

per cent bad? Can you recognize the seeds of the principal

cultivated plants? Germinate some beet seeds. What per cent comes

up? Can you explain? Collect for your school as many kinds of wild

and cultivated seeds as you can.














Let each pupil grow an apple tree this year and attempt to make it the

best in his neighborhood. In your attempt suppose you try the following

plan. In the fall take the seed of an apple--a crab-apple is good--and

keep it in a cool place during the winter. The simplest way to do this

is to bury it in damp sand. In the spring plant it in a rich, loose

soil.



Great care must be taken of the young shoot as soon as it appears above

the ground. You want to make it grow as tall and as straight as possible

during this first year of its life, hence you should give it rich soil

and protect it from animals. Before the ground freezes in the fall take

up the young tree with the soil that was around it and keep it all

winter in a cool, damp place.



Now when spring comes it will not do to set out the carefully tended

tree, for an apple tree from seed will not be a tree like its parent,

but will tend to resemble a more distant ancestor. The distant ancestor

that the young apple tree is most likely to take after is the wild

apple, which is small, sour, and otherwise far inferior to the fruit we

wish to grow. It makes little difference, therefore, what kind of apple

seed we plant, since in any event we cannot be sure that the tree grown

from it will bear fruit worth having unless we force it to do so.





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