BEST TIME FOR SOWING SILVER FIR IN THE NURSERY 1 
By J. V. Hofmann 
Forest Examiner , Wind River Forest Experiment Station 
INTRODUCTION 
Early attempts to grow silver fir (.Abies grandis ) at the Wind 
River Nursery, Carson, Wash., resulted in almost complete failure. 
One exception, however, was a successful sowing in the late spring. 
Since the previous losses were nearly all due to damping off, this 
singular success was attributed to the later date of sowing and the 
inactivity of the damping-off fungi after the soil had warmed. In 
order to correlate successful germination with time of sowing and 
soil temperature, the following experiment was undertaken. 
METHOD 
The unit seed bed area used was one-half of a standard 4 by 12 
foot bed, making the unit 4 by 6 feet. The first bed was sown on 
November 16; the second on March 25 of the following spring, the 
earliest date.it was possible to work the soil. The series was then 
continued at about 10-day intervals. 
The seed used was gathered in the fall just before the first sowing, 
at Red Mountain, on the Columbia National Forest, at about 4,000 
feet elevation. It was extracted by air drying where gathered, and 
was then shipped to the Wind River Nursery and stored in sacks in 
a cool, dry room. A cutting test on November 15 showed the seed 
to be 39 per cent good, 10 per cent wormy, and 51 per cent bad. 
Another cutting test March 21 following showed 36 per cent good, 
12 per cent wormy, and 52 per cent bad. There were 12,550 seeds 
per pound. Sowing was at the rate of 2,500 good seeds per bed, 
based on weight and cutting test. 
The fall-sown bed remained unshaded, as did the spring-sown beds, 
until the middle of June, when 50 per cent shade was applied. The 
shades were left off to prevent damping off and to produce a warmer 
soil in the seed beds. 
The seed beds were not allowed to become dry but the watering 
was done at a time when the surface would dry soon after, to prevent 
damping off. 
Soil-temperature readings were taken at 1-inch and 6-inch depths 
at intervals of about three days. 
Germination, mortality, and survival counts were taken daily 
from April 17, one week before germination began, until August 15, 
the close of germination. These counts were made in three areas 
in each bed, each area being 2 feet by 6 inches. Hence 3 square 
feet were counted. These areas were permanently marked with 
pegs and cord at the time of sowing. The seedlings were marked 
with colored toothpicks, each color indicating a one-week age class. 
. Causes of mortality were determined by cultures from dead or 
dying seedlings. 
i Received for publication October 31, 1924; issued September, 1925. 
Journal of Agricultural Research, 
Washington, D. G 
( 261 ) 
Vol. XXXI, No. 3 
Aug. 1, 1925. 
Key No. F-21 
