=Experiment.=—­Fill some tumblers or teacups or tin cans with wet sand and others with clay that has been wet and then thoroughly stirred till it is about the consistency of cake batter or fresh mixed mortar.  Take a tumbler of the wet sand and one of the wet clay and plant two or three kernels of corn in each, pressing the kernels down one-half or three-quarters of an inch below the surface; cover the seeds and carefully smooth the surface.  In other tumblers plant peas, beans, and other seeds.  Cover the tumblers with saucers, or pieces of glass or board to keep the soil from drying.  Watch them for several days.  If the clay tends to dry and crack, moisten it, fill the cracks and smooth the surface.  The seeds in the sand will sprout but those in the clay will not (see Fig. 38).  Why is this?  Water fills the small spaces between the particles of clay and shuts out the fresh air which is necessary for the sprouting of the seeds.

This teaches us that when we plant seeds we must so prepare the soil, and so plant the seeds that they will get enough fresh air to enable them to sprout, or, in other words, the soil must be well ventilated.

=Experiment.=—­Plant seeds of corn and beans in each of two tumblers; set one out of doors in a cold place and keep the other in a warm place in the house.  The seeds kept in the house will sprout quickly but those outside in the cold will not sprout at all.  This shows us that seeds will not sprout without heat.

If the weather is warm place one of the tumblers in a refrigerator.

Why don’t we plant corn in December?

Why not plant melons in January?

Why not plant cotton in November?

The seeds of farm crops may be divided into two classes according to the temperatures at which they will germinate or sprout readily and can be safely planted.

Class A. Those seeds that will germinate or sprout at an average temperature of forty-five degrees in the shade, or at about the time the peach and plum trees blossom: 

Barley           Beet            Parsley
Oats             Carrot          Parsnip
Rye              Cabbage         Onion
Wheat            Cauliflower     Pea
Red Clover       Endive          Radish
Crimson Clover   Kale            Turnip
Grasses          Lettuce         Spinach

These can be planted with safety in the spring as soon as the ground can be prepared, and some of them, if planted in the fall, live through the winter.

Class B. Those seeds that will germinate or sprout at an average temperature of sixty degrees in the shade, or when the apple trees blossom: 

Alfalfa          Soy Bean        Squash
Cow Pea          Pole Bean       Cucumber
Corn             String Bean     Pumpkin
Cotton           Melon           Tomato
Egg Plant        Okra            Pepper

We are now ready to answer the question:  What conditions are necessary for seeds to sprout or germinate?  These conditions are: