NURSERY PRACTICE ON THE NATIONAL POBESTS. 33 



ing, the seed is in its most delicate condition and most subject to loss 

 of vitality from drying out. When germination activities are once 

 started they should not be checked by lack' of water. Moreover, in- 

 sufficient water may cause seed to lie over until the following year 

 before germinating. An uneven-aged stand of seedlings will result. 

 This condition is a nuisance in nursery practice because it necessi- 

 tates close grading of the stock when it is dug. The moisture con- 

 dition most conducive to germination is that where the soil is 

 simply fresh or only slightly moist but not w r et. An extremely 

 moist or wet soil is not conducive to rapid germination, and may 

 cause the seed to rot. It is not possible to preserve absolutely uni- 

 form moisture conditions in the seed beds continuously, but the nearer 

 such conditions can be approached the better will be the germination. 



Beds should be watered only often enough to prevent their drying 

 out. The periods of watering will vary so extremely w r ith the char- 

 acter of the season, the soil, and the nature of the covering given 

 the beds that no definite rules can be framed. Inspection of the beds 

 is the only safe guide. It is better to water often and moderately 

 than a few times and heavily. This may mean from once a week or 

 even 10 days under rather favorable conditions or where mulching 

 is practiced to twice a day during very hot, dry weather. When 

 necessary to water daily, it is better to water in the evening than in 

 the morning. When watered in the evening a bed remains moist 

 until the next morning at least, and perhaps until noon. Thus it is 

 sufficiently moist for 18 or 20 hours. When watered in the morning 

 on a clear, warm day, a bed is likely to become dry by sundown, be- 

 cause the greatest evaporation occurs during the middle of the day. 

 Watering later than 3 p. in., however, is considered poor practice 

 at the Pilgrim Creek Nursery, because the seed beds then remain cold 

 over night. The time of watering must thus be related to the daily 

 range in temperature where wide extremes occur. 



When fall sowing is practiced or when a rainy season follows sow- 

 ing, the necessity of watering during the germination period will 

 ordinarily be obviated. In Arizona and New Mexico beds thoroughly 

 soaked before early spring sowing of seed which sprout quickly, and 

 then covered with burlap and about one-half inch of soil, do not 

 need watering during the spring. 



A number of methods may be employed : By hand with the hose, 

 by means of garden sprinklers, or by irrigation. The first is slower 

 than the others, but is unquestionably the best from the standpoint 

 of efficiency under all conditions. The water can be distributed 

 evenly in the form of a fine spray to all parts of the beds. Lawn 

 sprinklers are more rapid because as many of them as the water 

 pressure will permit can be kept going at one time. They do not 

 63186°— Bull. 479—17 3 



