SEEDS AND SEEDLINGS 163 
After the rest period the time required for germination 
varies greatly. Grains, grasses, and many seeds of herbs of 
the Pea family germinate in from two to eight days, and seeds 
of most plants of the Parsley family in about fourteen days. 
The seeds of the hornbeam and ash are said not to grow 
until the second spring after they are planted. 
154. Seed testing. In growing crops from the seed it is 
desirable to use only seed of the highest quality. The seed 
should be of one of the best varieties, that is, a choice kind 
of grain, beet, tomato, or other plant, which is adapted to 
the soil and climate of the region.1 Good seed is pure and 
of high vitality. Purity means freedom from earth, sticks, 
broken seeds, bits of leaf, or weed seeds. High vitality 
means a large percentage of vigorous live seeds which, under 
good conditions, will grow. The purity can be tested by exam- 
ining a small average sample of the seed with a good lens and 
separating the sound seeds of the desired plant from foreign 
seeds and other impurities. The vitality can be tested by 
sprouting a convenient number of seeds, one lot from each 
sample to be examined. Place the counted seeds on mois- 
tened blotting paper in a plate and cover them with an in- 
verted plate. If many seeds fail to grow, it is because (1) the 
seeds have been kept too long and have lost their vitality ; 
(2) the seeds have been exposed to too great heat or moisture, 
or to too sudden changes in temperature; (3) the seeds were 
immature or otherwise imperfect when collected. The use of 
impure seeds or those of low vitality is extravagant, no matter 
how cheaply they were bought, as impure seeds may introduce 
many bad weeds, and seeds of low vitality will not give a good 
stand of the grain or other crop planted.? 
1 See Chapter XIT. 
2 The teacher can usually secure a bulletin on seed testing from the 
agricultural experiment station of his state. 
See also Lyon and Montgomery, Examining and Grading Grains, Ginn 
and Company, Boston; Burkett, Stevens, and Hill, Agriculture for Begin- 
ners, Ginn and Company, Boston; and Warren, Elements of Agriculture, 
The Macmillan Company, New York. 
