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



Whether seed rows should be ridged or not is largely determined 

 by season of sowing. Ridging serves several purposes. It delays 

 drying out of the topsoil beneath the ridge, assuring to the seed a 

 uniform moisture for germination; it marks the row, thereby facilitat- 

 ing cultivation and irrigation, which are sometimes necessary before 

 germination takes place; and it keeps the seed from being washed 

 out by excessive heavy rains or blown out by hard winds, and to a 

 certain extent prevents pilfering by birds and rodents. Furthermore, 

 in the process of raking down the ridge after the seed starts to sprout, 

 but before the sprouts reach the ground level, the first crop of weeds 

 is removed. If the weeds are allowed to come up with the plants, 

 they can be pulled only by a great amount of hand labor and, on 

 weedy soil, only at the sacrifice of a considerable number of young 

 plants. 



Ridging of seed rows is recommended in all cases where fall sowing 

 is practiced. For spring sowing its employment is a matter of judg- 

 ment on the part of the nurseryman. Ordinarily, in the spring, if soil 

 moisture conditions near the surface are good and the species sown is 

 one that can be expected to germinate in several days, ridging need 

 not be practiced. An overhead sprinkling system reduces the neces- 

 sity for ridging. 



Moisture, oxygen, and proper temperature are the three essentials 

 for germinating seed, and if these factors are not held within certain 

 limits, no germination will occur. It is obvious, therefore, that the 

 ridge must not be too high and should not be packed too hard. For 

 fall sowing, ridge heights up to 5 or 6 inches are required for pro- 

 tection, largely from frost heaving and premature germination; but for 

 spring sowing, ridges 3 inches high are adequate. Higher ridges pre- 

 vent heat and air from penetrating to the seed and, if the ground is 

 wet for long periods, may cause the seed to rot. 



GERMINATION AND SEEDLING CULTURE 



All the cultural activities following the sowing of the seed up to 

 the time that germination is complete, have been grouped by the 

 writers under the term "germination culture." More specifically, the 

 following operations are included in this term : Raking down or remov- 

 ing ridges, breaking crust, and any irrigating or cultivating that is 

 intended as an aid to germination. In the plains region, nurserymen 

 have found that careful germination culture is quite important, 

 particularly with light-seeded species and in heavy soil. The term 

 " seedling culture" as used here includes all cultural operations 

 involved in bringing the seedling crop to maturity from the time 

 germination is completed. More specifically, it includes the opera- 

 tions of thinning, control of growth, cultivating, weeding, irrigating, 

 hardening off, and top pruning. 



Care During Germination 



The removing or raking down of ridges requires good judgment 

 as to technique in performing the job and the time at which it is done. 

 The high ridges thrown up over the seed rows in fall sowing should be 

 partially removed as soon as the danger of premature germination is 



