74 MISC. PUBLICATION 4 3 4, U. S. DEPARTMENT OF AGRICULTURE 



Seedling bands not more than 2 to 3 inches wide are preferred; 

 wider bands greatly increase hand work and therefore weeding costs. 

 The rows should be straight and the edges of the bands sharply defined, 

 since this facilitates all cultural operations. 



Figure 20. — Green ash seedlings with a 10-inch space between rows, grown under 



overhead irrigation. 



Season of Sowing 



Sowing of deciduous species in the nursery may be carried on in 

 spring, summer, or fall. With the double objective in mind of 

 premium-grade seedlings and high germination, nurserymen have 

 found that each species presents its own problem and that it is highly 

 important to determine the optimum sowing season for each. 



Table 20. — Row spacing and seedlings per foot of row needed to produce 150,000 



seedlings per acre 



Distance between rows, 

 center to center (inches) 



Total 

 length 

 of row 

 per acre 



Usable 

 seedlings 

 per foot 



Distance between rows, 

 center to center (inches) 



Total 

 length 

 of row 

 per acre 



Usable 

 seedlings 

 per foot 



45___ 



Feet 

 11,616 



12, 446 



13, 403 



14, 520 



15, 840 

 17,424 



Number 

 12.9 

 12.1 

 11.2 

 10.3 

 9.5 

 8.6 



27 



24 



21 '.. 



18... 



Feet 

 19, 360 

 21, 780 

 24, 891 

 29, 040 

 34, 848 



Number 



42 



6.9 



39... 



6.0 



36 



5.2 



33 



15... 



4.3 



30 .. 











In general, the nature of the seed dormancy determines for all 

 species the optimum time of sowing. Species having embryo dor- 

 mancy, or a combination of embryo dormancy and impermeable seed 

 coat, respond either to fall sowing, which is sometimes preferable, or 

 to stratification followed by spring sowing. Species possessing only 



