36 PRACTICAL PLANT PROPAGATION 



6. Treating with acids or alkalis. Seeds with a hard, bony 

 covering are frequently treated with weak acids which serve to soften 

 the seed coat. If Raspberry or Blackberry seeds are soaked hi vin- 

 egar their germination will be hastened. 



Sweet Peas are treated with sulphuric acid, commercial strength, 

 for half an hour, then thoroughly washed. Old seeds or those with 

 a very hard, dark coat will frequently germinate after this treatment 

 when they would not otherwise. With the increased growing of 

 Sweet Peas which produce but few seeds, such as the Winter Flower- 

 ing Spencers, it has become highly desirable that each of the expen- 

 sive seeds germinate. White and mottled seeds do not usually need 

 acid treatment. It is suggested that should seed fail to germinate 

 without treatment it be sifted from the soil and steeped in acid. 



Many of the leguminous farm seeds fail to germinate because, 

 as the farmers say, they contain "hard seed." In dry seasons, es- 

 pecially, there frequently results a very poor germination. Experi- 

 ments have shown that Glover, Cotton, Alfalfa and some other seeds 

 benefit from such a soaking as advised above for Sweet Peas. 



In the Agricultural News of Barbadoes, West Indies, we read: 

 "If seeds are treated with chlorine water (two drops of chlorine to 

 60 c.c. of water) and then stood in the sun, they will germinate com- 

 pletely in six hours. The seeds must be removed from the chlorine 

 water, and washed, however, directly the radicle appears. Chlorine 

 has a decomposing effect on water in the presence of light, breaking 

 it up into hydrogen and oxygen, and the rapid germination is due 

 to the action of the nascent oxygen liberated by the chlorine. Hard 

 seeds need a preliminary soaking in water before steeping them in 

 chlorine solution. Alkaline substances, e. g., ammonia, soda, etc., 

 in highly dilute solution, also aid the process of germination. 



"Another curious method consists in watering the seeds with a 

 solution of formic acid (1 in 5000) at a temperature of 25 to 30 C. 

 This treatment dissolves the integument, and plants which normally 

 require eight or ten days will germinate in as many hours." 



SOWING SEEDS OF PERENNIAL FLOWERS 



In sowing the seeds of perennial flowers, coldframes are used. 

 The seeds are sown in rows about six inches apart. After sowing, the 

 frames should be watered and the soil mulched with cut grass or a 

 layer of finely sifted, well decayed, manure. This mulch will serve 

 to keep the soil from drying out and prevent the formation of a 

 crust over the seeds. If the manure is used it will supply the seed- 

 lings with food. 



