tinue growth in the open air.
Sometimes asparagus is forced by placing frames, covered with sash, over
the plants in the field, the rows of asparagus being set rather close
together. This is considered a very profitable method by many market
gardeners. Another method of forcing asparagus in the field is to dig
ditches between the rows and fill them with fermenting manure. The
surface of the bed may also be mulched with manure. The latter plan is
extensively practiced by French market gardeners.

At the beginning of November the pathways between the beds of asparagus
are dug up about two feet in depth and width. The soil coming from the
pathway is divided very carefully and put about eight inches thick on
the surface of the bed. The trench is filled up with fresh stable
manure, not litter, and frames are placed on the bed. The manure should
rise as high as the top of the frames and the lights be entirely covered
with mats and litter to prevent the heat accumulating in the frame from
escaping. In about two or three weeks the asparagus begins to show
itself on the surface of the bed. Many market gardeners cover the whole
of the bed inside the frames to a thickness of three or four inches with
manure, to force the vegetation more quickly; but in this case the
manure must be removed when the asparagus begins to shoot. When the
shoots are about three inches out of the ground they may be cut. The
mats must be taken off in the daytime, but the heat must be well kept
up, else the roots and buds will fail to push. The beds are forced every
second year only. The gathering of the asparagus may continue for about
two months but no longer, or the plantation would be injured. When the
gathering is over the frames are taken away, and the soil which was dug
up from the alleys is put back again.

An ingenious method of forcing asparagus in the field by means of
shallow tunnels was devised and successfully carried out by Prof. J. C.
Whitten, at the Missouri Experiment Station, who gives the following
account in Bulletin No. 43:

[Illustration: FIG. 35--TUNNEL THROUGH THE ROWS OF ASPARAGUS FOR FORCING
STEAM THROUGH THE SOIL]

"The field selected for the experiment was planted to asparagus about
ten years ago. The plants were in fair vigor, though of a small variety.
The first section forced embraced six rows, four feet apart, and fifty
feet long. Fig. 35 shows this section with one tunnel uncovered.
Trenches were first made between the