30 
BULLETIN 479, U. S. DEPARTMENT OF AGRICULTURE. 
Wire mesh for covering the frames can be purchased in rolls 150 
feet in length and in widths of 4 feet for the top screen and 1 foot 
for the sides and ends of the frames. The 1-foot strip is cut in 
6-inch widths. Experience at Forest Service nurseries has demon- 
strated that screen as fine as three meshes to the inch is necessary to 
keep mice out of the seed beds. 
The cost of these frames complete, including a shade frame of 
lath, is from $3 to $7 each, depending upon the lumber used and the 
skill and wages of the men who construct them. Money can be saved 
by purchasing material which is surfaced on four sides, since it can 
SIDE VIEW OF FRAME 
TOP VIEW 
*y*Vz" 
Sw 
L 
o 
1 
/"x Z." 
SIDE VIEW 
Fig. 4. — Pettis seed-bed frame. 
be painted much more rapidly and requires less paint. Such frames 
ordinarily last only from 3 to 5 years or will need repairing by the 
end of that time. The bottom sill in particular is very liable to rot. 
At the old Garden City Nursery protective frames were used whose 
sides and ends were of 1 by 8 inch boards, the top only being cov- 
ered with wire screen. These were more satisfactory at this nursery 
because they afforded a better protection against wind, and were con- 
siderably cheaper than the wire frames. 
