This publication explains how to evaluate seed by considering the purity and germination percentages of the seed and calculating the actual cost of the good useable seed in the bag

Kinch, R. C.

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South Dakota State University Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange SDSU Extension Fact Sheets SDSU Extension 1974 Pure Live Seed R. C. Kinch Follow this and additional works at: https://openprairie.sdstate.edu/extension_fact Recommended Citation Kinch, R. C., "Pure Live Seed" (1974). SDSU Extension Fact Sheets. 1391. https://openprairie.sdstate.edu/extension_fact/1391 This Fact Sheet is brought to you for free and open access by the SDSU Extension at Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. It has been accepted for inclusion in SDSU Extension Fact Sheets by an authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For more information, please contact michael.biondo@sdstate.edu. Historic, archived doculllent Do not assume content reflects current scientific knowledge, policies, or practices. SDSU ® Extension For current policies and practices, contact SDSU Extension Website: extension.sdstate.edu Phone: Email: 605-688-4 792 sdsu.extension@sdstate.edu SDSU Extension is an equal opportunity provider and employer in accordance with the nondiscrimination policies of South Dakota State University, the South Dakota Board of Regents and the United States Department of Agriculture. Cooperative Extension Service U.S. Department of Agriculture South Dakota State University Brookings, South Dakota 57007 OFFICIAL BUSINESS Penalty for Private Use $300 Postage and Fees Paid (2-J U.S. Department of Agriculture .. AGR 101 U.S.MAIL Issued in furtherance of Cooperative Extension work , Acts of May 8 and June 30, 1914, in cooperation with the USDA Hollis D Hall , Director of Cooperative Extension Service , Sout h Dakota State Un1versIty, Brookings. Educational programs and materials offered without regard to age, race, color , rellg1on , sex , handicap or national origin . An Equal Opportu ni ty E·nployer File : 1.3-2M-74-2M-77--3,000 reprinted at estimated 4 cents each-1-78m~41A Pure Live Seed FS 182 by R. C. Kinch, Professor of plant science How much good seed is there in a bag? How good is the seed? How many pounds of worthless material ( seed that will not grow, inert material, weed seeds) does one buy when a bag of seed is purchased? These questions and many others may be asked every time a bag of seed is bought or put in a planter. The seed tag on each container of seeJ gives some information about the kind and quality of the seed. However, the actual quality of the seed is a combina-tion of many factors and unless all are considered the buyer does not have true knowledge of how much good seed actually is in the bag. Two of the more commonly considered items on the seed label are the pure seed (purity) and germina-tion percentages. A combination of these two gives a composite single figure, Pure Live Seed ( P.L.S. ), that shows the percentage of pure live seed. Pure live seed is an integrated quality expression and is derived by multiplying the pure seed by the germination. . Br ornegrass '-.. )' Purt, .I 88 . 45 In, rt > fa11cr 11 · 1 q • 24 '. :111v· & ;\ 'u rnhtr of Seu~ndarv 's 0010th \ V eed Seeds · '- ~: /, /S. ,., C'ermin~tion . , Dote Te,tc<l 1 / 1/7 1• . Origin S. n;:ik. The bromegrass seed tag shows 88.45% pure seed and 91 % germination. To determine the pure live seed multiply the pure seed (88.45%) by the germination (91 %) and divide by 100. 88.45 X 91 = 80.48o/ 100 Jo The P.L.S. figure (80.48%) shows only about 80% of the material in the bag is good bromegrass seed and about 20% or one-fifth is worthless as far as plant-ing is concerned. A pure live seed percentage may be determined on any other kind of seed that has been tested including small seed legumes such as alfalfa, sweet clover, red clover, etc., that have hard seeds. To determine pure live seed on a sweet clover seed lot labeled: pure seed 99.45%, germination 65~~' and hard seeds 22% , ad<l the germination and hard seeds (65% + 22% = 87%), multiply by pure seed (99.45%) and divide by 100. 99.45 X 87 = So.52% 100 Not all hard seeds are live seeds but if the seed has a bright color, is well cleaned, and is relatively free of immature or shrunken seeds practically all of the hard seeds are alive at the time of the test. Since P.L.S. indicates the per cent of good seed in a seed lot, it can be used to com pare seed lots to deter -mine which is the higher in quality. Also, minimum p1,1re live seed standards can be es~ablished for differ-ent kinds of seeds to assure a specified quality of seed. SEED PRICE DETERMINATIONS After the pure live seed figure is determined, the actual cost of the good seed in a bag can be calculated by dividing the cost per pound of seed by P.L.S. If the bromegrass seed in the first example is being sold for 35c per pound, the cost per pound of pure live seed is calculated by dividing the cost per pound (35c) by P.L.S. (80.48%). 35c • --- = 43c ( cost per pound pure live seed) 80.48% Actually the good usable seed is costing 43c per pound rather than 35c. When the price per pound is known'., comparisons can be made· between seed lots to determine which lot is the best buy. The highest qualjty seed offered for sale on the market is usually the best buy because lower quality seed generally is not discounted proportionally to the reduction in pure live seed content. 

Pure Live Seed

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Pure Live Seed

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