4 BULLETIN 521, U. S. DEPARTMENT OF AGRICULTURE. 
OUTLINE FOR SOILS AND CROPS— FIRST YEAR. 
(One unit.) 
HOW PLANTS GROW. 
(Nine lessons, three double periods for practical work.) 
Reference : Any modern high-school text in botany. 
Lesson 1. — Development of a Plant from the Seed. 
1. What the seed represents. 
2. Conditions essential to development. 
3. Vitality of seeds. 
4. Parts of seed and plantlet. 
5. Testing seeds. 
Illustrative material : Germinating seeds of different types. 
Exercise 1. — Germination Test of Seeds. 
Purpose: Testing for viability and to determine conditions essen- 
tial to germination. 
Directions: Secure a quantity of wheat or any small hardy seed 
known to be fresh, and another lot of the same kind of seed known 
to be at least 10 years old. Have each student count out 50 to 100 
seeds of each sample and place them in a plate between moistened 
Canton flannel or blotting paper. With a slip of paper to designate 
the sample, this seed should be covered with another plate or a piece 
of glass to prevent too rapid evaporation of moisture. (Paper pie 
plates, one within another, if kept moist, serve well without blotters 
or cloths. ) These plates of seeds should be kept in a warm room and 
enough water added to keep the seeds moist but not wet. The class 
as a whole should take three samples of the fresh seed, one to be kept 
moist, but placed where it is cold ; the other two to be kept in a warm 
place, but one lot kept covered with water to exclude air, and the 
other allowed to become dry. At the end of six clays the tests should 
show results in a vigorous germination of the fresh seed kept warm 
and moist and a lesser degree of vigor in the old seed and those sam- 
ples deprived of warmth, moisture, and air. 
Record and report: Each student should make a record of how 
the tests were made and write a report bringing out answers to the 
following questions: What per cent of the old and the fresh seed 
germinated ? Why did the old seed lack vigor in germination ? Why 
did the seed covered with water fail to germinate well? What 
effect did the low temperature have upon the seeds? What was the 
effect of the lack of moisture? What conditions are essential to the 
germination of seeds? Under what conditions should farm and gar- 
den seeds be tested for viability? (Tables showing optimum, mini- 
mum, and maximum temperatures at which common seeds germi- 
nate and the number of years various kinds of seeds remain viable 
will prove helpful in connection with a study of germination.) 
