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United States Standards

for Grades of Onion 

Sets

Effective September 6, 2016
This issue of the United States Standards for Grades of Onion Sets (81 FR 51297)

supersedes the previous issue which has been in effect since Feburary 1, 1940.

Voluntary U.S. grade standards are issued under the authority of the Agricultural 

Marketing Act of 1946, which provides for the development of official U.S. grades to 

designate different levels of quality. These grade standards are available for use by 

producers, suppliers, buyers, and consumers. As in the case of other standards for 

grades of fresh and processed fruits, vegetables, and specialty crops these 

standards are designed to facilitate orderly marketing by providing a convenient 

basis for buying and selling, for establishing quality control programs, and for 

determining loan values.

The U.S. grade standards and inspection instructions for all fresh and processed fruits,

vegetables, and specialty crops are available on the internet and upon request at the 

address below. These documents provide detailed interpretations of the grade standards 

and provide step-by-step procedures for grading the product.

Grade standards are issued by the U.S. Department of Agriculture (USDA) after careful 

consideration of all data and views submitted during rulemaking. The Department 

welcomes suggestions for improving the standards in future revisions. Comments may be 

submitted to, and copies of standards and inspection instructions obtained from:

Director, Specialty Crops Inspection Division

Specialty Crops Program,

USDA, Agricultural Marketing Service

1400 Independence Avenue, SW, STOP 0240

Washington, D.C. 20250

__________________________________________________________________________

Authority: 7 U.S.C. 1621-1627.

Note: Compliance with the provisions of these standards shall not excuse failure to 

comply with the provisions of the Federal Food, Drug, and Cosmetic Act, or 

with applicable State laws and regulations.

Non-Discrimination Policy: In accordance with Federal civil rights law and U.S. Department of Agriculture (USDA) civil rights 

regulations and policies, the USDA, its Agencies, offices, and employees, and institutions participating in or administering USDA 

programs are prohibited from discriminating based on race, color, national origin, religion, sex, gender identity (including gender 

expression), sexual orientation, disability, age, marital status, family/parental status, income derived from a public assistance program, 

political beliefs, or reprisal or retaliation for prior civil rights activity, in any program or activity conducted or funded by USDA (not all 

bases apply to all programs). Remedies and complaint filing deadlines vary by program or incident. 

Persons with disabilities who require alternative means of communication for program information (e.g., Braille, large print, audiotape, 

American Sign Language, etc.) should contact the responsible Agency or USDA’s TARGET Center at (202) 720-2600 (voice and TTY) 

or contact USDA through the Federal Relay Service at (800) 877-8339. Additionally, program information may be made available in 

languages other than English. 

To file a program discrimination complaint, complete the USDA Program Discrimination Complaint Form, AD-3027, found online at 

http://www.ascr.usda.gov/complaint_filing_cust.html and at any USDA office or write a letter addressed to USDA and provide in the letter 

all of the information requested in the form. To request a copy of the complaint form, call (866) 632-9992. Submit your completed form 

or letter to USDA by: (1) mail: U.S. Department of Agriculture, Office of the Assistant Secretary for Civil Rights, 1400 Independence 

Avenue, SW, Washington, D.C. 20250-9410; (2) fax: (202) 690-7442; or (3) email: program.intake@usda.gov. USDA is an equal 

opportunity provider, employer, and lender.
United States Standards for Grades of Onion Sets (September 6, 2016)

1

United States Standards for Grades of Onion Sets

Section Page No.

General........................................................................................................................... 2

§51.3980 General........................................................................................................ 2

Grades............................................................................................................................ 2

§51.3981 U.S. No. 1.................................................................................................... 2

§51.3982 U.S. No. 2.................................................................................................... 3

Reserved........................................................................................................................ 4

§51.3983 Reserved. .................................................................................................... 4

Definitions...................................................................................................................... 4

§51.3984 Similar varietal characteristics. .................................................................... 4

§51.3985 Mature. ........................................................................................................ 4

§51.3986 Fairly firm..................................................................................................... 4

§51.3987 Damage....................................................................................................... 4

§51.3988 Serious damage by tops.............................................................................. 5

§51.3989 Diameter...................................................................................................... 5
United States Standards for Grades of Onion Sets (September 6, 2016)

2

General

§51.3980 General.

(a) These standards are recommended to the onion set industry as a basis for 

determining the quality of onion sets. Among other requirements of these 

standards, it will be noted that onion sets must meet certain size specifications in 

order to grade U.S. No. 1 or U.S. No. 2. Although factors such as maturity and 

freedom from damage by disease, sprouts, etc., are very important, the size of

onion sets is the principal factor which has caused confusion and dissatisfaction 

between sellers and buyers.

(b) It has been a general practice to buy and sell onion sets as having passed 

through a certain size and type screen. Such a method of selling does not 

always give a true picture of the size of the sets. For example, sets described as 

having been passed through a 15/16 inch bar screen may actually have a 

considerable percentage ranging from 1 inch to 1-1/4 inches or more in diameter 

if the onions are flat shaped. On the other hand, if the field run of sets is 

generally small, there may be practically none over 1 inch in diameter after 

having passed through the 15/16 inch bar screen.

(c) In order to insure that most of the sets in a lot are not close to the maximum size, 

U.S. No. 1 grade requires, unless otherwise specified, at least 50 percent of the 

sets, by weight, to be 3/4 inch and smaller but not smaller than 5/16 inch in 

diameter. The U.S. No. 1 grade designation may not be used, however, on lots 

of sets having less than 40 percent 3/4 inch and smaller in diameter.

(d) It is thought that contracting on the basis of uniform standards which have actual 

size specifications for the sets, regardless of the size and type of screen used, 

will prove satisfactory to the trade. Actual size specifications rather than a mere 

statement that the sets have been passed through a certain size screen, should 

furnish the prospective buyer a truer picture of a lot of sets and serve as a more 

definite basis for the settlement of disputes.

Grades

§51.3981 U.S. No. 1.

“U.S. No. 1” consists of onion sets of similar varietal characteristics which are mature, 

fairly firm, free from decay and from damage caused by tops, sprouting, freezing, mold, 

moisture, dirt, chaff or other foreign matter, disease, insects, or mechanical or other 

means.

(a) The minimum size shall be not less than 5/16 inch in diameter. The maximum 

size shall be not more than 1 inch in diameter. Unless otherwise specified, at 

least 50 percent, by weight, of the sets in the lot shall be 3/4 inch and smaller: 

Provided, That the percentage specified shall not include any sets less than 5/16 

inch in diameter: And provided further, That the “U.S. No. 1” designation shall 
United States Standards for Grades of Onion Sets (September 6, 2016)

3

not be used on lots of sets that have less than 40 percent from 5/16 to 3/4 inch,

inclusive.

(b) Other maximum sizes smaller than 1 inch may be specified in connection with 

the grade in terms of fourths, eighths, or sixteenths of an inch as “U.S. No. 1, 3/4-

inch maximum”, “U.S. No.1, 7/8-inch maximum”, “U.S. No. 1, 15/16-inch 

maximum”, in accordance with the facts. Percentages less than 50 but not less 

than 40 must be specified in connection with the grade and percentages greater 

than 50 for sets which are from 5/16 to 3/4 inch in diameter may be specified as 

“U.S. No. 1, 40 percent 3/4 inch and smaller”, “U.S. No. 1, 65 percent 3/4 inch 

and smaller”, etc., in accordance with the facts. A range in diameters may also 

be specified as “U.S. No. 1, 3/8 to 7/8 inch” provided the lot has 40 percent or 

more of sets 5/16 to 3/4 inch in diameter.

(c) Tolerances. In order to allow for variations incident to proper grading and 

handling, the following tolerances, by weight, are provided as specified:

(1) For defects. Not more than a total of 6 percent of the onion sets in any 

lot may fail to meet the requirements of the grade, including therein not 

more than 2 percent for onion sets affected by decay and not more than 2 

percent for dirt, chaff, and other foreign matter.

(2) For size. Eight percent for onion sets which are larger than the specified 

maximum size and percent for onion sets which are smaller than the 

specified minimum size.

(3) No part of any tolerance shall be used to reduce the percentage of onion 

sets in any lot which is specified to be within any range from 5/16 to 3/4 

inch in diameter.

§51.3982 U.S. No. 2.

“U.S. No. 2” consists of onion sets which meet the requirements of U.S. No. 1 grade 

except that they shall be free from serious damage by tops and except for size 

requirements.

(a) The minimum size shall be not less than 5/16 inch in diameter. The maximum 

size shall be not more than 1-1/8 inches in diameter. Unless otherwise specified 

at least 50 percent, by weight, of the sets in the lot shall be 7/8 inch and smaller:

Provided, That the percentages specified shall not include any sets less than 

5/16 inch in diameter.

(b) Other minimum sizes may be specified in connection with the grade as “U.S. No. 

2, 3/8 inch minimum”, “U.S. No. 2, 1/2 inch minimum”, etc., in accordance with 

the facts. A maximum size of 1-1/16 inches may also be specified. Percentages 

other than that specified for sets which are from 5/16 to 7/8 inch inclusive in 
United States Standards for Grades of Onion Sets (September 6, 2016)

4

diameter or a range of diameters may also be specified as “U.S. No. 2, 60 

percent 7/8 inch and smaller”, “U.S. No. 2, 3/4 to 1-1/8 inches”, etc., in 

accordance with the facts. When a minimum size larger than 5/16 inch, or a 

range of diameters is specified in connection with the grade, there is no 

requirement as to the percentage of sets from 5/16 to 7/8 inch in diameter.

(c) Tolerances. In order to allow for variations incident to proper grading and 

handling, the following tolerances, by weight, are provided as specified:

(1) For defects. Not more than a total of 6 percent of the onion sets in any 

lot may fail to meet the requirements of the grade, including therein not 

more than 2 percent for onion sets affected by decay and not more than 2 

percent for dirt, chaff, and other foreign matter.

(2) For size. Eight percent for onion sets which are larger than the specified 

maximum size and 3 percent for onion sets which are smaller than the 

specified minimum size.

(3) No part of any tolerance shall be used to reduce the percentage of onion 

sets in any lot which is specified to be within any range from 5/16 to 7/8 

inch in diameter.

Reserved

§51.3983 Reserved.

Definitions

§51.3984 Similar varietal characteristics.

“Similar varietal characteristics” means that the sets are the same general type.

Onion sets of different colors shall not be mixed in the same container.

§51.3985 Mature.

“Mature” means that the sets are dry and well cured.

§51.3986 Fairly firm.

“Fairly firm” means that the set may yield slightly to moderate pressure but is not 

appreciably soft or spongy.

§51.3987 Damage.

“Damage” means any defect, or any combination of defects, which materially detracts 

from the appearance of the lot, or the shipping or planting quality of the individual sets.

Any lot of sets shall be considered as damaged; when more than 30 percent, by weight, 

of the sets have tops over 2-1/2 inches in length. Sets which have sprouts over 1/4 inch 
United States Standards for Grades of Onion Sets (September 6, 2016)

5

in length shall also be considered as damaged.

§51.3988 Serious damage by tops.

“Serious damage by tops” means that more than 50 percent, by weight, of the sets in 

any lot have tops over 2-1/2 inches in length.

§51.3989 Diameter.

“Diameter” means the smallest dimension measured through the center at right angles 

to a line running from the stem to the root.