PLS refers to the percentage of live seed by weight in a seed lot having the potential to develop into a seedling. Live seed refers to the germination percent, dormant seed and hard seed. The remaining seed in the lot contains inert matter, other crops and/or weed seeds and is not viable.
Pure Seed – Viable and non-viable seed of the desired species.
% Purity – Percentage of pure seed by weight.
% Germination – Percent of seed by weight having the potential to germinate relatively quickly.
% Total Germination – Percent of seed by weight composed of hardseed, dormant seed, and germination percentage having the potential to produce a seedling.
% Hard Seed – Percent of viable seed having a hard seed coat that can take longer to break and germinate.
% Dormant Seed – Percent of viable seed taking longer to germinate, other than hard seed.
% Nonviable Seed – Percent of seed that will not germinate.
% Inert Matter – Material other than seed.
Viable Seed – Pure seed having the potential to produce a seedling.
Weed Seed – Seeds or other reproductive parts of species recognized by law as weeds.
Other Crop Seed – Seeds that are not weeds or pure seed.
Percent Total Germination = (Germination + Hard Seed + Dormant Seed)
70 + 15 + 5 = 90% Total Germination
Use that figure and the purity percentage to calculate the PLS percentage.
Multiply Total Germination by Purity / 100 = PLS %
(95% X 90%)/100 = 85.5% of Pure Live Seed
85.5% of this seed lot by weight has the potential to grow. If 10 pounds of pure live seed is needed on a site, the quantity of bulk seed needed is determined by:
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