72 Gardening 
Things to Do and Observe 
1. To observe how soil is made. Search inroad cuts, along river 
banks, and other places where rock is exposed. Note that in 
some of these places the compact rocks are crumbling into the 
small particles that make soil. 
2. To observe the formation of humus. Examine the surface 
soil in a forest, or if this cannot be done, examine a compost heap. 
Note that this soil contains parts of plants in various stages of 
decay. Observe also its color and texture. What is the color of 
soils that lack humus? 
3. To observe soil particles and granules. Crush and examine, 
first with the eye and then with a hand lens, dry, finely pulverized 
samples of various soils (clay, humus, sand, and loam). In 
which are the particles or granules largest? smallest? Compare 
as to uniformity in the size of the granules. 
4. To show the effect of working soils when they are too wet. 
Secure some dry, finely powdered clay or soil in which clay pre- 
dominates, and two large shallow dishes or pans. Place one 
quart of the clay in the first dish, flood with water and stir, leaving 
the clay in irregular, sticky masses. 
Place the same amount of clay soil in the second dish, add the 
same amount of water as was added to the first dish, but do not 
stir. 
Allow the soil in the two dishes to become quite dry. Note that 
the soil that was stirred is in hard lumps which do not readily 
break up into granules. Is the soil in the second dish more 
easily cultivated ? ; 
This experiment shows how particles of clay soil may become 
grouped into large lumps if worked before the excess of water 
has dried out. Why is a soil of coarse lumps unsuited for plant- 
ing seeds and growing crops? What should the gardener do to 
such a soil? 
Repeat the above experiment, using first sand and then loam. 
Are these soils more easily cultivated when wet than is a clay soil? 
5. To determine when a garden soil is dry enough for cultivation. 
Fill a flat two-thirds full of clay soil, another with the same amount 
of sand, and a third with loam. Flood each to the top of the flat 
with water. Allow the excess of water to drain off through the 
cracks in the bottom of the flat. Test each soil, as described 
