Seed Quality

Providing High Quality Seed is Important to Us

Applewood is one of the few seed companies that maintains its own seed testing laboratory which is managed by a Registered Seed Technologist. We test all of our seeds to insure that seed quality meets state and federal seed standards. The lab carries out seed sampling and testing to determine viability and purity of each seed lot. Noxious weed exams are also performed to insure that seed lots pass state and federal noxious weed requirements. Our lab follows AOSA (Association of Official Seed Analysts) rules which provide standards for handling samples and carrying out tests and exams.

Viability Testing

Viability testing includes germination and tetrazolium (TZ) tests. Tetrazolium tests give a quick estimate of germination potential. Germination tests typically take several to many weeks, but there are some species that will not germinate for many months or even for over a year. For these species, a TZ test may be the only accepted option for viability testing.

Applewood Seed Viability Percentages

Most of our individual seeds and mixtures have a total seed viability percentage of between 70-95%. The total viable seed percent is equal to the seed germination percent, plus the hard seed percent and/or dormant seed percent. Hard seeds have impermeable seed coats and cannot imbibe water during seed testing. Dormant seeds are viable but will not germinate immediately when adequate moisture and temperature are present. Seed dormancy is created by specific physical or physiological conditions that prevent the seed from germinating at the time of seed testing.

Applewood Seed Purity

Most of our individual seeds and mixtures have a purity of 95-99%. A purity analysis has four components which are based upon weight: % pure seed, % crop seed, % inert matter, and % weed seed. When you buy a bag of seed, our tags will clearly state the percentages of germination, dormant and/or hard seed, pure seed, crop seed, inert, and weed seed. A test date for the germination will also be shown on the tag.

Understanding PLS

Sometimes seed is sold on a PLS (Pure Live Seed) basis. If your project requires PLS amounts, feel free to get quotes from our sales staff. The PLS is obtained by multiplying the percent purity by the percent total viable seed and then dividing by 100. To convert a PLS seed quantity to the bulk amount, simply divide it by the PLS in decimal form. For instance, if a seed lot has a PLS of 84.03 and you need 5 PLS pounds, divide 5 by 0.8403, which equals 5.95 bulk pounds. If you need to convert bulk pounds to a PLS amount, simply multiply it by the PLS (in decimal form) of the seed lot. For example, using the same lot above with a PLS of 84.03, 5 bulk pounds multiplied by 0.8403 equals 4.20 PLS pounds.

More Wildflower Planting Guide Resources

Tetrazolium Test for Viability