Hardy and Tender Seeds 161 



equal to twice their diameter. This applies well to 

 greenhouse conditions, in which the soil is very finely 

 prepared and kept continuously moist ; but in the 

 open ground, the seeds are usually planted deeper 

 than this. 



Horticultural plants are ordinarily divided into three 

 classes in respect to their hardiness: (1) hardy, or 

 those able to withstand the vicissitudes of climate in 

 a given place ; (2) half-hardy, or able to withstand 

 some frosts or other uncongenial conditions ; (3) ten- 

 der, or wholly unable to withstand frost. Seeds of 

 the hardy plants may be sown in the spring as early 

 as the land can be made fit, or even in the fall. 

 Examples of such seeds are sweet pea, onion, leek. 

 In the northern states, however, very few seeds are 

 sown in the fall ; but the land is often prepared in 

 the fall, and the seeds are sown as soon as the soil 

 is dry enough in the spring. The seeds of half-hardy 

 plants, as beets and lettuce, may be sown two or three 

 weeks before settled weather is expected to come' 

 that is, when it is still expected that there will be 

 hard frosts. Tender seeds, as beans, tomatoes, egg- 

 plants, cucumbers, melons, are sown only after the 

 last frost has occurred and when the ground is 

 thoroughly settled and warm. 



Of plants which are normally transplanted, it is 

 better to start the seeds in a seed-bed. These beds 

 may be in the forcing -house, hotbed or coldframe ; 

 or, if it is not desired to force the plants beyond the 

 normal season, it may be made in the open. There 

 are three chief advantages in sowing seeds in a seed- 



