In order to assure your project obtains the highest possibility of success, there are a number of details
about seeds and the seed industry that are beneficial to know. First, seed certification and seed testing
and labeling are extremely important aspects of the seed industry that should be well understood before
ordering and receiving your seed shipment. Seed certification is accomplished by members of the
Association of Official Seed Certifying Agencies which are located in each state (contact aosca.org). Seed
should be sampled and tested following rules published by the Association of Official Seed Analysis.
Labeling is regulated by the Federal Seed Act and by state seed laws. Second, the development of seed
mixes is another important aspect of a successful seeding. Often, there is more to the development of a
seed mix than meets the eye. Third, choosing the right seeding technique is also an important planning
process to assure the most success possible in your restoration project. Mulching options are discussed in
section 4.
Seed Certification
The seed industry is required by law to provide a seed analysis label that lists the crop kind or species and
the variety. Certified seed has a separate tog or label attached to the bag meaning the seed inside has been
verified by a third party certification agency. Seed is specified by either a Certified Seed Blue Tag, a
Source Identified Yellow Tag, or Variety Not Specified (VNS) tag. The meaning of each of these is
explained below.
Certified Seed Blue Tag – The gold standard. This is the only way to know for certain that you
will receive a desired variety. The seed should be bought in the original bag with the Certified Seed Blue
Tag. Blue Tagged Certified Seed must meet high purity and germination standards and have a low weed
content, usually less than 0.25%.
Source Identified Seed (Yellow Tag) –Certified Blue Tag seed is not always available for many
native species, thus it is acceptable to buy native seed if the seed was sourced within a climate zone
similar to where the seed is to be planted. You may request the state and county of origin of the seed you
intend to purchase, however, state seed law only requires that the actual state of origin be on the label. To
assure seed is received from a designated area, it is
strongly recommended to request ‘Source Identified
Seed’ to ensure that a certification agency has verified
the exact location from which the seed was harvested.
To ensure the receipt of
Yellow tags do not guarantee that the seed is free of
Certified Seed, Purchase
noxious weeds, so be sure to refer to the vendor’s label
Orders should contain the
for analysis and weed content or better yet, send away
following language: “Certified
another sample of the seed to be tested.
Seed with blue tags attached to
the seed bag shall be supplied
Additionally, the seed industry also sells seeds labeled as
where a named variety is
‘Variety Not Stated (VNS)’ when the source is not
specified. The vendor shall
known or when there may be an oversupply of a
indicate on the bid whether
particular variety. VNS seed should be priced similarly
Certified or common seed is
to commonly available seed as there is no proof as to its
being offered, as well as the
origin.
origin of the seed. The blue
tags which are removed to mix
the seed shall be given to the
revegetation project manager.
Special Considerations
In addition, mix tags showing
It is always best to request the most weed AND
the weighted averaged of the
OTHER CROP free seed lot the vendor has available.
ingredients shall be attached to
Many seed mixes show minimal weed seed, but many
each bag. “ (Dunne and Dunne
1996)
projects have been overrun by undesirable crop species such as yellow sweet clover, alfalfa, annual rye or
other species as these species are categorized as other crop seed rather than weed seed.
If you choose to buy mixed seed, be aware of some hidden risks. For example, if Blue Tagged Certified
Seed is specified in the mix, there is no way to ensure that certified seed will be used. The buyer should
request the blue tags removed from the bags of certified seed used in the mix and saved for the buyer.
Additionally, lower quality, weedy lots can be blended into the mix. If you do purchase mixes, send a
sample for purity and germination testing to a seed laboratory following AOSCA (National Association
of Seed Certification Agencies rules.
UNTAGGED BAGS
Even though a bag may not have a blue tag, it may still contain the variety claimed, but be careful!
It is not worth the risk if a specific variety or germplasm source is critical to the success of the project. A
seed lot may fail certification because purity was slightly lower than the standard for that variety or seed
suppliers may not go to the trouble and expense of having their products inspected by the seed certifying
agency since certified seed often does not command a much higher price than common seed.
Seed Testing
Each seed bag must come with an ‘Analysis Label.’ Only accept seed with a complete analysis label on
the bag as well as a current germination test conducted by an accredited laboratory. On the tag should be:
Variety and Kind – the Kind is the species, and a variety (or VNS) should be stated.
Purity – Purity is defined as the actual proportion of seeds of the desired species present in the bagged
material. Purity + inert matter (chaff, etc) + other crop seed + weed seed percentages must add up to 100
percent. Grass and grass like seed should contain no more than 10 to 15 percent inert matter or it will be
difficult to plant.
Inert matter – This can include seed chaff, stems or other plant bits that did not get cleaned out of the
mix.
Other crop seed – Some species that are often considered contaminants in the seed mix fall into this
category. This can include species such as yellow sweet clover, alfalfa, cereal rye or wheat, which can
become just as troublesome as some types of weeds in the right (or wrong) circumstances.
Weed Seed – Most weed species are termed as ‘common weeds.’ Many states have maximum limits for
weed seed (e.g. 0.5% in Utah). Noxious weed species are of two types;’ Prohibited’ – zero weeds are
allowed and ‘Restricted’ - allows a minimal number per pound or percentage in the seed lot.
It is important to know that each state has different lists of prohibited noxious weeds and restricted
noxious weeds. If buying seed from out of state or if the origin of the seed is from out of state, request
that the seed be tested with an “All-States Noxious Weed Exam” to be sure to get all the information
needed about the seed mix.
Germination Germination numbers should include the sum of all seeds germinated plus hard seed and
dormant seed. In general, germination percentages of graminoids should not be lower than 60%, but shrub
and forb species vary widely by species.
Pure Live Seed (PLS) – PLS is the percent purity multiplied by the percent germination. Most species
are sold on a PLS basis, with the price adjusted accordingly. It is always preferable to buy seed on a PLS
basis