8 
BULLETIN 479, U. S. DEPARTMENT OF AGRICULTURE. 
not, in the aggregate, produce such disastrous results as in o large 
one. •Furthermore, the time suitable for field planting can be util- 
ized more readily with locally grown stock. Trees raised in nurseries 
at a lower elevation, for example, may begin vegetation before con- 
ditions on the planting site permit setting them out, and the best time 
for planting a warm, early site may pass before stock can be fur- 
nished from a nursery in a colder situation. On the other hand, 
because of the closer and more efficient supervision in the large 
nurseries, as well as better facilities for tending the stock, a greater 
proportion of the plants normally survive to the age of field plant- 
ing, and the better care given the stock results in its being more 
fully developed and, other conditions being equal, more able to suc- 
ceed under field conditions. The concentration of the work at large 
nurseries makes for efficient management, good stock, and low cost 
of production. 
A central nursery should have a capacity of at least a million 
plants. This is desirable as a matter of economy, for the larger 
the nursery the more opportunity there will be for intensified work, 
the S3^stematizing of each operation, and regular supervision. By 
these means the cost per thousand plants may be reduced; three 
or four million seedlings can be grown at a lower cost per thousand 
than one or two million. A large capacity is desirable for two other 
reasons besides the economy that may be effected : It is an insurance 
against a shortage of plants due to unforeseen losses, and heavy 
grading is possible in well-stocked nurseries, so that in each case very 
nearly the class of stock required may be furnished. 
The actual area of a nursery is determined by the output that is 
desired, the species, the area occupied by paths and roads, the spac- 
ings. the class of stock produced, and the practice followed in the 
rotation of crops. Possible rotation of crops being disregarded, 
the following table indicates the area, exclusive of paths and roads, 
necessary for the growing of 1,000.000 seedlings and transplants 
yearly. 
Table 1. — Seed-bed area 1 in square feet, necessary to produce 1,000,000 seed- 
lings [/early. 
Length of time in seed 
beds. 
Number of seedlings per square foot. 
100 L5 l'O 175 200 225 250 27"> 300 
Area in square feet.- 
1 year 20,000 
2 rears '40,000 
3 years ,G0, 000 
13,333 
26,667 
40, 000 
10,000 
20, 000 
30, 000 
8,000 
16,000 13,334 
24,000 20,000 
5,714 5,000 
11,428 10,000 
17,142 13,000 
4,444 
8,888 
13,332 
4.000 
8,000 
12,000 
3,636 
7,272 
10,908 
3,333 
6,666 
10.000 
1 Add 25 per cent in seed beds and from 10 to 20 per cent in transplant beds to alio 1 
for losses. 
2 1 acre=43,560 square feet. 
