24 PLANT PROPAGATION 



cause each species has its own preferences ; but large 

 seeds may be sown two to four times their diameters 

 and small ones only slightly covered just enough to 

 hide them from the light. Fresh and strong seeds may 

 be sown deeper than old or weak ones, because the seed- 

 lings should reach the surface with less difficulty. 



FIG. 18 PROPAGATING BENCH SHADED WITH NEWSPAPERS 



Notice the burlap curtains beneath the bench. These give several degrees of 

 bottom heat when lowered. 



39. Light hinders some seeds from sprouting (poppy, 

 adonis, larkspur), but has no apparent effect upon others. 

 Its influence upon germination is not fully understood. 

 Seeds of mistletoe, Spanish moss and many orchids ger- 

 minate as well in light as in dark places, perhaps even 

 better. 



For these reasons it is considered advisable to shade 

 fine seeds and spores while germinating. Nothing is to 

 be gained by the reverse process. When covered with 

 soil they are usually shaded enough, but when sown 

 upon or very near the surface they sprout better 

 when shaded at least partially. Parsley, thyme, mar- 

 joram and other slow-sprouting and small seeds do best 



