New seedings and spriggings require intensive
irrigation to ensure successful establishment. Seedings require
light and frequent watering to ensure that the seed and surface of
the soil are constantly moist. Plan to keep the soil moist for up
to 30 days following planting. During hot days this may
necessitate 3 or 4 light waterings during the day to provide
adequate moisture for rapid and successful germination. If the
soil dries out during the germination process, the seedling is
likely to die. Areas sodded and plugged also require intensive
irrigation. However, frequent light watering is only required
until the sod or plug is rooted. Once sod or plugs are rooted,
irrigate every second or third day.
Begin mowing the new lawn when the height of grass is
1/3 greater than the intended mowing height. Be sure that the lawn
mower is sharp. A dull mower tends to pull grass seedlings out of
the ground or causes leaf blade tips to be bleached or white. Try
to minimize traffic on the new lawn until it is mature. Broadleaf
weed control may be necessary. Do not apply broadleaf weed control
to new lawns until they have been mowed two times. Begin a good,
comprehensive fertilization program as outlined below.
A well planned (and simple) fertility program is
essential to turf maintenance. Turfgrass requires 16 basic
nutrients for growth. Most of these are available to turf from
soil, but not in proper amounts for proper growth. Turfgrass
fertilizers usually have some mixture of the most abundantly
needed nutrients. The ones needed in the greatest amounts are
N-P-K. Sulphur as a fertilizer component is sometimes included,
since it is beneficial in lowering our high pH soils. See the
appropriate lawn calendars and fertilization guidelines for
fertilizer rates and application dates.
Fertilizer Terms for Lawns
Fertilizer Analysis or Grade:
The fertilizer analysis or grade is the percent by weight of the
fertilizer product of the individual fertilizer element(s). The
numerical contents on the label usually contain three values for
the fertilizer analysis. These include the amounts of nitrogen
(N), phosphorous (P), and potassium (K). If the fertilizer
contains any one of these, it must include content
values for the other element(s) as well. If they do not exist,
then a "0" must appear on the label for that element.
For example, a (21_7_14) fertilizer is 21% nitrogen, 7%
phosphorous and 14% potassium, by weight. A (21_0_0) fertilizer is
21% nitrogen, but has no phosphorous and no potassium. A (16_20_0)
fertilizer has 16% nitrogen, 20% phosphorous, and no potassium (by
Some commonly used quick release fertilizers
that are readily available commercially are: ammonium sulfate
(21_0_0), ammonium phosphate (16_20_0), ammonium nitrate (34_0_0),
potassium nitrate (13_0_44), calcium nitrate (19_0_0),
superphosphate (0_27_0), triple_superphosphate (0_45_0), and
potassium sulphate (0_0_45).
Other "brand name" fertilizers usually
contain mixtures of these products as blended products. These can
have any analysis or grade combinations. Examples include
(21_7_14), (10_20_10), etc.
Fertilizer ratio is the relative amount of N to P to K in a
fertilizer. The fertilizer ratio is easily calculated by dividing
the lowest grade number into each of the other grade numbers on
the label. For example, on a (21_7_14) fertilizer, divide the 7
into each grade value for N_P_K. This results in a 3_1_2 ratio
fertilizer. Note that fertilizers with the same ratio do not have
to have the same grade. A (30_10_20) fertilizer has a 3_1_2 ratio
(just like the 21_7_14) but its analysis is much higher.
Many commercial lawn fertilizers are available in
ratios of 3_1_2, 4_1_2, or 2_1_2. This is based on plant demands
and general soil characteristics.
A complete fertilizer includes some amounts of all three of the
major elements of N_P_K. It does not say how much is present
(analysis or grade). It does not say in what relative amounts
(ratio). Examples of complete fertilizers include (20_15_5) and
34_10_6). Note that fertilizers such as (33_0_0) or (15_0_20) are
not complete, because they lack having all three elements of
A starter fertilizer is usually one which is high in phosphorous
(P). It may or may not contain other elements as well. Usually,
contents of 20% (P) or more are termed starter fertilizers.
Superphosphate (0_27_0), triple_superphosphate (0_45_0), and
ammonium phosphate (16_20_0) qualify as starter fertilizers.
Generally, starter fertilizers should be applied to turfgrass
soils before establishment, after overseeding, or during a
Regular fertilization programs should include knowledge
of the basic times of the year that the turf is growing, and
secondly, some extreme soil conditions which may be present. On
sandy based soils, it is usually wise to apply a complete
fertilizer, since phosphorous and potassium may be lacking
somewhat. On more heavily textured soils (loams, clays, silty
soils, etc.), regular fertilizations can be made with high
nitrogen fertilizers since P_K are usually available. One
application per year should be of a complete fertilizer, on these
soils as well.
Listed in the lawn maintenance calendars are suggested
guidelines for popular Arizona turfgrasses.
Fast vs. Slow Release
Fast release fertilizers dissolve in water quickly and can be
taken up readily by the turf. Since they dissolve quickly, they
can burn the turf since the fertilizers are actually salts. Slow
release fertilizers are those which exhibit "slow"
chemical reactions in the soil in order to make the nutrient
available over a larger period of time. There are other types of
slow release fertilizers which have coatings which will break down
slowly, or have small pores in the fertilizer pellets which "ooze"
out the fertilizer over time. New technologies for slow release
fertilizers are being developed. Slow release fertilizers should
be used only during active growth periods. This is during summer
for warm-season grasses and the spring and fall for cool-season
grasses. Do not apply a full years fertilizer requirement in
More emphasis is being placed on potassium or potash
(K) fertilization. Some researchers believe that K should be
applied in at least 50% of or equal to the amount of nitrogen. K
is beneficial for food storage, root growth, and minimizing many
plant stress factors.
Iron containing fertilizers are beneficial in promoting
good turf color, without the excess growth sometimes experienced
with nitrogen containing fertilizers. Ferrous sulphate is
inexpensive, but may be short-lived in our high pH western soils.
Cheleated irons are more effective but more expensive and are used
on high profile turfs.