This last fact brings us to another very important property of soils.  Soils have existing in them many very small plants called bacteria.  They are so very small that it would take several hundred of them to reach across the edge of this sheet of paper.  We cannot see them with the naked eye but only with the most powerful microscopes.  Some of these minute plants are great friends to the farmer, for it is largely through their work that food is made available for the higher plants.  Some of them break down the organic matter and help prepare the nitrogen for the larger plants.  Others help the leguminous plants to feed on the nitrogen of the air.  To do their work they need warmth, moisture, air, and some mineral food; these conditions we bring about by improving the texture of the soil by means of thorough tillage and the use of organic matter.

CHAPTER IX

SEEDS

CONDITIONS NECESSARY FOR SEEDS TO SPROUT

In the spring comes the great seed-planting time on the farm, in the home garden and in the school garden.  Many times the questions will be asked:  Why didn’t those seeds come up?  How shall I plant seeds so as to help them sprout easily and grow into strong plants?  To answer these questions, perform a few experiments with seeds, and thus find out what conditions are necessary for seeds to sprout, or germinate.  For these experiments you will need a few teacups, glass tumblers or tin cans, such as tomato cans or baking-powder cans; a few plates, either of tin or crockery; some wide-mouth bottles that will hold about half a pint, such as pickle, olive, or yeast bottles or druggists’ wide-mouth prescription bottles; and a few pieces of cloth.  Also seeds of corn, garden peas and beans.

=Experiment.=—­Put seeds of corn, garden peas, and beans (about a handful of each) to soak in bottles or tumblers of water.  Next day, two hours earlier in the day, put a duplicate lot of seeds to soak.  When this second lot of seeds has soaked two hours, you will have two lots of soaked seeds of each kind, one of which has soaked twenty-four hours and the other two hours.  Now take these seeds from the water and dry the surplus water from them by gently patting or rubbing a few at a time in the folds of a piece of cloth, taking care not to break the skin or outer coating of the seed.  Place them in dry bottles, putting in enough to cover the bottoms of the bottles about three seeds deep; cork the bottles.  If you cannot find corks, tie paper over the mouths of the bottles.  Label the bottles “Seeds soaked 24 hours,” “Seeds soaked 2 hours,” and let them stand in a warm place several days.  If there is danger of freezing at night, the bottles of seeds may be kept in the kitchen or living room where it is warm, until they sprout.

Observe the seeds from day to day.  The seeds that soaked twenty-four hours will sprout readily (Fig. 36), while most, if not all, of those that soaked only two hours will not sprout.  Why is this?  It is because the two-hour soaked seeds do not receive sufficient moisture to carry on the process of sprouting.