22 PRINCIPLES OF PLANT CULTURE 



The water should be heated only to 110° or 120° F. and the 

 soaking may be continued until the seeds have fully swollen. 

 Soaking is most important with seeds having seed- 

 cases that do not readily transmit water at growing tem- 

 peratures, as in the honey locust, canna, thornapple or 

 hawthorn, holly, peony and the like (27). Such seeds, 

 particularly if they have been allowed to become dry, are 

 generally soaked in hot water until swollen, before planting, 

 otherwise they might lie in the ground for months and 

 even years before germinating. In treating such seeds 

 with hot water, unless the temperature at which they 

 swell is known, the water should be heated very gradually 

 until the seeds begin to swell, when it should be maintained 

 at that temperature until they are fully swollen. It is 

 said that seeds of the honey locust may be immersed for 

 a time in boiling water without destroying their viability, 

 but such treatment is not to be recommended for any seeds. 



36. Cracking seed-case. — Germination is sometimes 

 hastened in seeds of this class by cracking or cutting away 

 part of the seed-case. To favor the absorption of water, 

 nurserymen often drill or file a hole through the seed- 

 cases of date or other seeds having bony seed-cases, or 

 crack dry peach and plum pits in a vise or with an imple- 

 ment resembling a nutcracker (27). 



37. Failure to germinate. — Seeds may fail to germi- 

 nate from a variety of causes, even when exposed to the 

 proper degree of warmth, moisture and oxygen. They 

 may be too old (164), they may not have been suflSciently 

 mature when gathered (162), they may have become too 

 dry (168), they may have been subjected to freezing before 

 sufficiently dry (166), they may have been stored while 

 damp and thus subjected to undue heating, or they 

 may have been damaged by insects or fungi (321) either 



