Sometimes the appearance of a package will show whether the seed has been kept in stock a long time. It is, however, much more difficult to find out whether the seeds are pure. You can of course easily distinguish seeds that differ much from those you wish to plant, but often certain weed seeds are so nearly like certain crop seeds as not to be easily recognized by the eye. Thus the dodder or "love vine," which so often ruins the clover crop, has seeds closely resembling clover seeds. The chess, or cheat, has seeds so nearly like oats that only a close observer can tell them apart. However, if you watch the seeds that you buy, and study the appearance of crop seeds, you may become expert in recognizing those that have no place in your planting.
One case is reported in which a seed-dealer intentionally allowed an impurity of 30 per cent to remain in the crop seeds, and this impurity was mainly of weed seeds. There were 450,000 of one kind and 288,000 of another in each pound of seed. Think of planting weeds at that rate! Sometimes three fourths of the seeds you buy are weed seeds.
In purchasing seeds the only safe plan is to buy of dealers whose reputation can be relied upon.
It not seldom happens that seeds, like corn, are stored in open cribs or barns before the moisture is entirely dried out of the seeds. Such seeds are liable to be frozen during a severe winter, and of course if this happens they will not sprout the following spring. The only way to tell whether such seeds have been killed is to test samples of them for vitality. Testing is easy; replanting is costly and often results in a short crop.
Fig. 62. Impurities in Seeds
Tube 1 represents one pound of redtop grass as bought; Tube 2, amount of pure redtop grass seeds in Tube 1; Tube 3, amount of chaff and dirt in Tube 1; Tube 4, amount of weed seeds in Tube 1; Tube 5, amount of total waste in Tube 1; Tube 6, amount of pure germinable seeds in Tube 1
EXERCISE
Examine seeds both for vitality and purity. Write for farmers' bulletins on both these subjects. What would be the loss to a farmer who planted a ten-acre clover field with seeds that were 80 per cent bad? Can you recognize the seeds of the principal cultivated plants? Germinate some beet seeds. What per cent comes up? Can you explain? Collect for your school as many kinds of wild and cultivated seeds as you can.