15. SEED TESTING. 



Illustrative material: Procure an ounce of clover seed and as 

 many small patty pans as there are pupils. Put 100 seeds of 

 red or white clover in the seed tester. Put in enough seeds of 

 oats, barley, Indian corn, peas, beans, and cucumber or melon 

 to supply each pupil with at least four of each kind. 



Before taking up the lesson, remove the cover of the seed 

 tester, and the upper cloth, and pass the open tester about the 

 class, after which remove, with a forceps, the clover seeds that 

 have failed to germinate, leaving all the other seeds. Count the 

 ungerminated clover seeds, and let the pupils subtract the num- 

 ber from 100. Explain what is meant by the per cent of 

 germination; i. e., the number of seeds per hundred that will 

 germinate. 



At the close of the lesson, give each pupil a thimbleful of commercial 

 clover seed in a patty pan. Require each pupil to separate the seed from 

 the impurities. Estimate the relative amounts of each. Of what do the 

 impurities consist? 



Use of Seed Tester. We learned in Lessons 13 and 14 

 the soil conditions that are necessary for the germination 

 of seeds. We now learn that seeds of various kinds ger- 

 minate as freely in the seed tester as when planted in moist 

 soil. By means of the seed tester, we can easily find out, 

 before we plant them,- whether or not a sample of seeds can 

 germinate. 



Age Affects Germination Not all seeds can ger- 

 minate, even though they appear all right outside. Seeds 

 germinate less freely as they become old, and after a 

 certain age they lose their power to germinate. Some 

 kinds of seeds retain their power to germinate much 



longer than others. 



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