Page 316 - Moving the Earth_ The Workbook of Excavation

LANDSCAPING AND AGRICULTURAL GRADING

7.10 THE WORK

One way to make a lawn is to use a rotary tiller or a plow and a harrow to turn in the existing
growth, and pulverize the soil for planting of grass seed. It is usually good practice to bury the old
vegetation several weeks before planting. Decay of vegetable residues often temporarily deprives
the soil of nitrogen to such an extent that the new crop cannot obtain enough for a start. Also,
sprouts from roots of undesirable plants can be readily destroyed as they appear on bare ground,
and can be reduced or eliminated before planting.
A less expensive method, which is usually satisfactory, is to pull out any brush, then mow the
field repeatedly. It may be reduced in one operation from field length to lawn length, then kept
short, but better results are apt to be obtained from starting with a high cut as if for hay, and pro-
gressively trimming shorter.
The effect of the cutting is to kill or place at a disadvantage plants that prefer to grow tall, and
to encourage those which are not damaged by mowing. Most fields contain enough lawn-type
grass and clover to take over the whole area within a year when encouraged by repeated cutting.
A similar effect may be obtained by moderate driving and parking of cars and trucks on the
field. Field surface may be too rough for a lawn. Large inequalities may have to be cut or filled.
Smaller ones can be rolled down, filled with dirt, or both.
A power lawn mower having heavy steel or rubber rolls will tend to flatten ground. Its effect is
quite marked when inequalities are small and choppy and the soil is soft, and becomes negligible
as the ground bakes in the summer.
A steel wheel roller, weighing from 3 to 5 tons, of the type used in driveway construction and
blacktop patching, is a very effective lawn flattener, but must be used when soil is in the right con-
dition. If soil is too soft, it will make ridges, and probably get stuck. Heavy wet soils may pack so
hard as to discourage growth.
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Hollows may also be filled with topsoil. This may be applied in layers ⁄ 4 to ⁄ 2 inch thick so that
grass will grow up through them, or the fill made to the level of the surroundings on one lift, then
new seed planted where necessary. Sometimes the seed is mixed with the topsoil prior to placing it.
Fills of more than an inch or two on bare ground, and any fill over grass, tend to settle notice-
ably so that the work will require doing over, although with less material, the following year.
Overfilling enough to compensate for this settlement requires expert judgment. Firm tamping is
sure to reduce this difficulty and may eliminate it, but might make it difficult for existing grass to
push up through the new soil.
Planting Grass. Soil should be loosened and smoothed before planting. If the area is too large for
hand digging and raking, a rotary tiller of appropriate size is the preferred tool. A plow and a disc har-
row, or a harrow only, followed by dragging with a plank will often do a good job. Fertilizer, lime,
manure, peat moss, or other soil-enriching materials are best mixed in by hand or machinery. If the area
is large, a spike-tooth harrow can be used for both smoothing over the ground and covering the seed.
After the machinery is finished, the ground is hand-raked. This looks simple but is not. A certain
knack is required to get a smooth surface.
Soil acidity can be tested with litmus paper and color scales that are obtainable at garden supply
and drug stores. Most lawn grasses like pH 6. If the soil is pH 5, about 75 pounds of ground limestone
should be added to each 1000 square feet. A pH of 4 will call for 100 to 200 pounds for the same area.
Slaked or hydrated lime has a higher calcium content, 100 pounds of it being equivalent to
about 135 pounds of ground limestone. Quicklime is still more concentrated, but is inconvenient
and dangerous to handle.
It is good practice to add some fertilizer, but the amount varies widely with circumstances and indi-
vidual judgment. If vegetation has been mixed into the soil within the last two or three weeks, either on
the spot or at the source from which it is being hauled, some nitrogen fertilizer must be added, to make
up for that borrowed by the decay processes. In general, an addition of a moderate amount of general
fertilizer is cheap insurance for the work and expense invested in preparing and planting the lawn.
Any of the lawn seed mixtures are good, and the differences can be explained by the store sell-
ing them. A mixture should almost always be used instead of a single kind, as each variety has its
own special and often obscure likes and dislikes in soil conditions. If several kinds are planted,
there is a good chance one of them will like the circumstances, and its vigorous growth will com-
pensate for any sulking by other varieties.