38 BULLETIN" 479, U. S. DEPARTMENT OF AGRICULTURE. 
at 8-foot intervals on both sides of the beds and 2 by 4 ? s are laid on 
and nailed to these uprights. This makes a line of stringers along 
each side of the bed extending its entire length. Strips of slat or 
lath fencing are rolled out over these stringers to furnish shade. The 
slatting can be handled by one man and can be quickly rolled up if 
cloudy weather makes this desirable; the stakes and stringers can 
easily be moved when it is necessary to plow or grade ; and the slat- 
ting is high enough above the ground so that weeding can be con- 
ducted without removing it. One man can construct about 400 linear 
feet of this type of frame per day. 
The posts and framework of the high frames occupy the ground 
constantly (PI. VIII). Durable first-class posts about 10 feet long 
are set in the ground in check rows from 10 to 12 feet apart, so 
that their tops are about 7 feet above the ground. Two sets of girders 
of rather heavy material (2 by 6's are preferable to 2 by 4's, as 
the latter are likely to buckle) at right angles to each other connect 
the tops of the posts. Over this framework rolls of slatting can be 
drawn. The framework must be substantially constructed because 
it is subject to considerable strain when the slatting is drawn across 
it and because the necessity often arises of a man Avorking on top 
of it. The rolls of slatting are usually long enough to stretch entirely 
across the frame and down to the ground on each side so as to afford 
side shade and also to act as a windbreak. They remain in place 
from spring until autumn, thus subjecting the plants to half shade 
during the whole of the season. At the Pilgrim Creek Nursery 
4 by 6 feet frameworks of slatting are used instead of the roll 
slatting. These are easier to handle, but are more easily broken. 
The high frames have some advantages over the low ones. They 
do not interfere with weeding, cultivation, or watering, so that an 
inspection of these operations can more easily be made. The working 
conditions beneath them are more pleasant during extremely hot 
weather than in the open. The light is more diffused than under 
low frames, which is desirable in especially hot regions or when the 
species grown are susceptible to injury from the sun's rays. Under 
them the paths are kept moist as well as the beds; there is less 
danger of the stock being harmed by unseasonable frosts; the soil 
seems less liable to bake and crust than under low frames; and 
since the slatting remains on during the entire growing season, less 
watering is needed than with low frames, which are often removed. 
Their cost of construction of 2J to 3^ cents per square foot is much 
less than that of the low wire protection and shade frames, and their 
life is considerably longer. 
Objections to the high frames are numerous. They do not give 
adequate protection against birds and rodents. Two or more men 
