SEED AND SEED SOWING. 67 



composition of water. In the presence of a superabund- 

 ance of moisture, fresh seeds may absorb more water than 

 they are able to decompose, and the death and subse- 

 quent rotting of the germs take place; for this reason 

 it is more advisable to sow in dry than in wet weather. 



The degree of heat necessary to start vital action varies 

 in different species, and depends upon their character 

 and composition, and the climate to which the plants 

 were indigenous. 



The most favorable temperature of the soil for the 

 germination of seeds of plants from cold climates, may 

 be stated at from fifty degrees to fifty-five degrees; 

 for those of green-house plants, at from sixty to sixty- 

 five degrees, and for those of the torrid zone, at from 

 seventy to eighty degrees. 



Of all the seeds sown by the truck-farmer, those of 

 the onion will germinate at the lowest temperature; other 

 conditions being favorable, they will sprout at a few de- 

 grees above freezing, while those of the melon and egg- 

 plant require a higher temperature. Healthy seeds of 

 some species may be exposed to a remarkably high de- 

 gree of temperature without impairing their vitality. 

 Seeds of raspberry have been known to grow which had 

 been picked from a jar of jam which must have been 

 heated to the degree of boiling syrup, or two hundred and 

 thirty degrees. 



To promote germination, seeds are sometimes soaked 

 in water heated to within a few degrees of the boiling 

 point, or about two hundred degrees, but this is only prac- 

 ticable with hard and healthy seed. The practice of 

 soaking seeds in water to soften the outside covering, or in 

 an alkaline solution having a strong affinity for carbonic 

 acid, or a substance able to supply a large quantity of 

 oxygen, like a dilute solution of oxalic acid, is only ad- 

 visable when the difference of a few days in the time of 

 germination is important, as for instance, in the case of 



