NURSERY PRACTICE ON THE NATIONAL FORESTS. 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 wet. 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 with 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. m., 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 
