Selection of the proper turfgrass variety for a lawn,
based on the site and intended use is the major factor in the
successful performance of a lawn. If you have selected a turfgrass
which will be established from the seed, the next question is to
acquire the seed for planting. In order to better understand
what's in the "seed bag," you should be able to read the
"seed tag." The seed tag is a legal document which
contains important information about the integrity and condition
of the variety(s) and other materials sold to you as the final
product. For seed that travels from state to state, Federal Seed
Act (FSA) requirements must be met which require the following
- Seed Lot Number: used for permanent identification.
- Kind of Seed: accepted or common crop name.
Examples are perennial ryegrass, tall fescue, common
- Percent Pure Seed: this is the amount of seed by
weight for each variety. This includes the name(s) of the
variety or varieties included. If no variety is claimed, then
VNS (variety not stated) appears on the tag.
- Other Crop Seed: this includes other unnamed
varieties of the desirable turfgrass species, or other species
of other grasses or crop seeds. This can be up to 5% by weight
of the seed bag.
- Weed Seed: this is the percent by weight of the
seed bag which contains either noxious weeds, and/or other
weed seeds. If noxious weeds are present, then usually strict
limits are imposed as tolerance limits.
- Inert Matter: this includes the amount of non-seed
materials by weight. Soil particles, broken seeds, awns and
short stems are items included in the percent inert matter.
Note: the amount of pure seed, other crop seed, weed
seed and inert contents equals 100%.
The seed tag also bears information regarding the
germination capability of the seed, which is tested under strict
laboratory conditions for each species.
The percent germination indicates what percent of the
actual seed itself will germinate (under optimum conditions). The
date (month and year) of the germination test is included on the
seed tag. For seed which travels as interstate commerce
(essentially all our cool season turf grasses are from other
states) the germination test information is applicable for a
period of five months after the test month. For instate seed
produced in Arizona (bermudagrass) the germination test is valid
for nine months.
Special seed treatments (if applicable) must be noted
on the tag as well. These treatments include any chemical or
temperature treatments to break seed dormancy (potassium
nitrate/cold storage, etc.). Any fungicide treatments to the seed
would be included here as well.
If the variety has an application for, or has received
a PVP (Plant Variety Protection) certificate, this too appears on
Blue Tag Certified Seed
This is the highest quality seed available. In order for turfgrass
seed to achieve blue tag status, the following conditions must be
- Fields have been planted with either approved foundation or
breeder seed, or established with certified planting stock.
- Variety is worthy of certification, or describable by the
- Production fields meet sanitation standards and are grown
with proper isolation distances (from other plants of the same
- The production fields have 0.03% or less off type plants.
- Minimum standards for purity are met.
- Other grass contamination limits are met.
These conditions when met, insure the buyer that the
best quality seed is available to them.
Pure Live Seed
It is important to take into consideration the actual amount of
seed which can be expected to germinate.
Two components of information on the seed tag allow you
to do this. These two items are (1) the percent pure seed, and (2)
the percent germination. If the seed is 90% pure, then the
remaining 10% is not seed at all. If the germination is 85%, then
on average 8.5 out of ten seeds will germinate. The remaining 1.5
out of ten seeds will not germinate. In order to find out how much
"good seed" will at maximum "germinate," you
must calculate the PURE LIVE SEED (PLS) INDEX. To do this, simply
multiply the percent purity times the percent germination.
From our discussion example above...
PLS = % purity X % germination
(0.90) X (0.85)
= 0.76, or 76%
This means that 76% of the product by weight will
germinate, under the best conditions. So a 50 pound bag of
perennial ryegrass seed will have a PLS content of 38 pounds.
Knowing this, the actual amount of seed required must be adjusted
by the PLS content.
For example, a 3000 square foot lawn is to be
overseeded at 20 lbs./1000 square feet with annual ryegrass. This
quickly figures to a convenient 50 pounds of seed required. But,
since the PLS content is 76% (0.76), we must now adjust and
calculate how much of the actual product we need.
50 lbs. divided by 0.76 (PLS) equals 66 lbs.
We now need 66 pounds of seed which has a PLS index of
76% to seed 3000 square feet of turf at the 20 pound seed rate.
Both tall fescue and perennial ryegrass seed may or may
not contain a beneficial fungus inside the seed. The seed is
called the ENDOPHYTE. This endophyte fungus causes tall
fescue and ryegrass plants in the lawn to produce natural chemical
substances inside the plant. These chemicals repel above ground
feeding insects. These include chinch bugs, flea beetles,
armyworms, cutworms and aphids, etc. However, below ground insects
(grubs) are not affected. The seed tag should say if the seed is
either ENDOPHYTE ENHANCED or ENDOPHYTE FREE. If it
does contain endophyte, it should say what percentage of the seed
is infested. While endophyte enhanced seed is good from a lawn
standpoint, it is unfavorable to use the same lawn seed for
pasture. Do not establish a pasture from endophyte containing
seed. Use it for lawns only.
Turf may be established from seed, sprigs, plugs, or
sod. The method depends on the type of grass desired, the
environmental conditions, time constraints, and financial
considerations. The same basic requirements for seed bed
preparation, fertilizer application, and watering apply for both
seeding and vegetative establishment. After the new lawn is
established and growing well, begin a good, comprehensive
maintenance program to keep it healthy and attractive (See
Soil quality and preparation are important steps in
planting a new lawn. Begin by removing the existing vegetation.
Use a non-selective herbicide like glyphosphate (Round-Up) to kill
the weeds that are growing. The weeds must not be moisture
stressed when they are sprayed. Let Round-Up dry on leaves for 12
hours. Dig into the soil and get a feel for the soil particles. Is
it mostly sandy, loamy, or very fine--clay like. Sandy soils drain
quickly, and have good root growth. The clay soils tend to drain
poorly and become compacted. Soils which have 50-60% sand and the
rest smaller particles are best for a lawn. It's much easier to
add fine soils to coarse sandy-soils, than to add large amounts of
sand to dense clay soils. Examine the soil and overall suitability
of the site. Is the soil heavy (clay) or light (sandy)? Does the
soil contain gravel or large stones on the surface, or just below
the soil? Were any items "dumped" on the site such as
chemicals, gas, oil, construction materials, cement or gravel? If
so, these should be removed. A soil test should be done in order
to add proper fertilizer types and amounts. The area should be
roto-tilled if the soil is compacted. Most soils can be
temporarily modified for planting by adding organic matter such as
plant parts, shredded bark, horse or cattle manure. To properly
add organic matter, do the following:
- Wet the soil and let it drain 2 days.
- Roto-till the soil as deep as possible.
- Wet the soil again and let it drain 2 days.
- Roto-till again.
- Add the organic matter on top of the tilled soil.
- Roto-till again as deep as possible.