Environmental Engineering Reference
In-Depth Information
approximate seeding rates for selected turf-grasses (rates are usually
printed on the seed label as well). In the tropics, especially the humid
tropics, seeding rates in the upper range are usually optimal. High
seedling density during the establishment period reduces weed pres-
sures and produces more competitive turf-grass plants. On the other
hard, seeding rates that are too high can extend the period of seedling
immaturity, and delicate, juvenile seedlings are less able to compete with
weeds and more easily infected by diseases.
Seeding depth
Most turf-grass seeds are very small and should be planted quite shal-
lowly, at about 0.5-cm depth. Applying the seeds to the surface and
lightly rake afterwards can produce the desired planting depth. Seeds
planted too deep may not germinate, or their germination may be
delayed.
Seeding Methods
The primary goal is to distribute seeds uniformly. Seeding by hand is
popular on small areas. Push-type spreaders, both broadcast and drop
types, are used on areas up to 1-2 ha. Tractor-mounted spreaders can be
used on larger areas. Spreaders used for seeding are the same as those
used for fertilizing (see Chapter 5, this volume). They must be calibrated
before use (see Appendix).
Overall, seeding warm-season grasses requires more effort than seed-
ing cool-season grasses. The seeds are very small, often slippery and
mostly dark in colour, so they are not visible on the ground. Filling the
spreader with seeds and applying them directly can be very risky. Small
imperfections in the spreader's gate opening may permit considerable
loss of seeds before their escape is noticed. The seeds should therefore be
thoroughly mixed with dry, preferably white, sand. The percentage of
sand is not important, but a proportion of 1 part seeds to 10 parts sand
usually works well. The spreader should be calibrated for the seed-sand
mixture. The desired amount of seed should be divided in half and
applied, with sand, in two passes over the area at right angles to each
other. This practice assures uniformity of coverage and prevents acciden-
tal skips. The visibility of white sand on the ground reveals any areas of
non-uniformity. Small areas such as home lawns can be seeded from a jar
with holes punched in the lid (Fig. 4.7). The desired amount of seed can
be mixed with five parts white sand. All at once or in several portions, the
seed-sand mixture is placed in the jar, which acting like a large salt-
