noxious weed exam
Seed Laboratory performs purity and noxious weed exams on a
wide variety of species. Upon request, tests can be analyzed
according to A.O.S.A., I.S.T.A. or Canadian Methods and
We also provide, on request, soil and
sclerotia tests that are required for shipping seed to
certain countries, like Japan.
For a list of required purity weights, please click
The Purity Test is an analysis that determines
the physical composition of a seed sample. The results of a
purity test are expressed in four components:
- Pure seed refers to the percentage by weight of
the pure seed units for the species under consideration.
- Other crop seed is separated from the
purity working sample. It consists of seeds of plants
grown as crops, other than the pure seed present. A
classification scheme for such seeds has been published by
A.O.S.A. in the Uniform Classification of Weed and Crop
Seeds, Handbook No. 25.
- Inert matter is separated from the purity working
sample. It consists of all material not classified as
seed. We generally define inert as broken seed, soil,
sclerotia, sticks, chaff, stone and plant material.
- Weed seed is separated from the purity working
sample. It consists of seeds, florets, bulblets, tubers or
sporocarps of plants recognized as weeds by laws, official
regulations, or by general usage.
The Noxious Weed Exam is done on a specified
sample size that provides approximately 25,000 units.
Noxious weed seed is a plant propagule that is specified by
law as being especially undesirable, troublesome, and
difficult to control.