Iowa Nut Growers Association (INGA)

INGA is an Iowa non-profit corporation founded in 1942 and incorporated in 1968 to promote:

  1. An interest in nut-bearing plants
  2. Scientific research in breeding and culture
  3. Standardization of varietal names
  4. Encouraging greater use of nut trees in Iowa Agriculture and home landscape plantings
  5. Dissemination of information on all of the topics above

Take some time an learn about the rich history of growing nuts in Iowa in the past, present, and future!


Want to learn more and stay in touch? Contact to join our email list.


Annual membership is $20.00 with checks made out to Iowa Nut Growers Association or INGA and mailed to the membership Secretary Patty Judas at the following address:

Patty Judas
1212 Bauch St
Waterloo, IA 50701

INGA 2023 Annual Nut Evaluation
Saturday, February 18th, 2023, Wickiup Hill Learning Center, Toddville, IA

Register Today on the Trees Forever Events Calendar, or simply click the link

Samples can also be mailed to Jeff Jensen, 3404 20th Ave, Fenton, IA 50539

See Nut Evaluation 101 below for details about the annual nut evaluation.

Nut Evaluation 101

The Iowa Nut Growers Association has been conducting an annual nut evaluation since at least the 1970's and continues this tradition to the present day. Folks have lots of questions about how samples are scored, the process we use, and how they can get involved. The below primer is modified from an article Al Beck wrote for a newsletter before the 2000 nut evaluation. Also included is a black walnut evaluation sheet so the reader can follow along and better understand what is being looked for and how a sample is scored.

  1. A proper sample for walnuts, hickories, and pecans is roughly 12 nuts; hazelnuts 20. Only 5 are actually scored for the walnuts, hickories, and pecans and 10 for hazelnuts. Select husk free and clean nuts for the sample. Keep nuts stored in a cool dry place (warm storage temperatures for pro-longed periods of time tend to cause the kernels to become rancid) and which have not been allowed to become excessively dry (very dry nuts allow the seal to open up and the kernels to become brittle leading to shattering of the kernel when the shell is cracked).
  2. Be sure to write your name and contact information on the sample bag for identification purposes. Please also include the variety name if it is known. Other information to include is whether it is a native or seedlings you planted.
  3. As the sample is checked in at the evaluation meeting a number code will be assigned to each sample. This number will be placed on the sample bag, sample tray, and evaluation sheet. This number code must be kept with the tray sample at all times during the evaluation process.
  4. To maintain consistency, the same person will visually rate (score) the external characteristics of all the samples according to the guidelines on the evaluation sheet and will assign a score for the following characteristics:
    • Seal: Tightly sealed nuts are the most desirable. The cleft crevice at the base of the nut is not a lack of seal; the seal is towards the apex or tip area of the nut.
    • Appearance: Uniformity in size and shape are most desirable along with lack of roughness
  5. Again, to maintain consistency, the same person cracks all samples.
  6. After cracking, the sample is taken to the scales for weighing. Note the weight is taken after cracking and not before; in case one of the nuts is bad and needs to be replaced. Also note the cracker must be careful to not lose any of the shell or kernel pieces otherwise the weights and subsequent calculations will be inaccurate.
  7. Next the sample is taken to the many pickers for extraction of kernels with the fingers only. These kernels are kept separate and labeled as "1st crack". Any kernels locked in the shell are then extracted with "nippers" and picks and kept separate and labeled as "2nd crack". The picker than takes the whole sample back to the scale for weighing of the samples.
  8. From there, the calculators will begin scoring the kernel characteristics. Again for uniformity, the same person will score the samples. The following parameters are used:
    • Number of 1/4 pieces - the more quarter pieces the better
    • Kernel size - the larger the kernel size the better
    • Color - a light bright color is most desirable
    • Veins - the less veining the better
    • Shrivel - non-shriveled kernels are the most desirable
  9. All 10 characteristics have now been scored resulting in a total grade. Scores can range from 10 (a perfect score) to 30 (worst score possible). A perfect 10 score is very rare.
  10. Now that the sample is graded we have one last calculation to make before determining a final score. The percent kernel is figured. The higher the better with any score above 30 being considered good. The highest kernel percentage recorded has been 38.5%.
  11. Three scoring methods ar used to compute a final composite score. Each method is outlined below:
    • McDaniels – The McDaniels method uses only kernel weight and number of ¼ pieces disregarding how well the nut grades out. A higher kernel weight generally tends to favor samples with large nuts; also if the kernel cavity is not so tightly packed or not as well filled, this results in easier extraction and more whole ¼ pieces boosting the score. A score of 80 or above is a superior nut. Cultivars that have scored well in the past include: El Tom, Markee Seedling, Krouse, Sparks 129, and Wright 753.
      The highest score ever recorded is a 93
    • Iowa #1 – The Iowa #1 method divides the total grade into the percent kernel, thereby including all 10 characteristics into the score. A score of around 250 and above is considered a superior nut. Cultivars that have scored well in the past include: Oldham, Sparks 127, Sparks 129, Sparks 147, and Sparrow.
      The highest score ever recorded is a 300
    • Iowa #2 - The Iowa #2 method is similar to the Iowa #1 method except that it squares the percent kernel weighting it more heavily than the grade. Thus, nuts with better percent kernel will do better under this scoring. A score of around 80 and above is considered a superior nut. Cultivars that have scored well in the past include: Oldham, Sparks 127, Sparks 129, and Sparks 147.
      The highest score ever recorded is a 114
    • Composite Score – By adding the McDaniels, Iowa #1, and Iowa #2 scores together we arrive at a total and final composite score. A score of around 400 and above is considered a superior nut. Cultivars that have scored well in the past include: El Tom, Hay, Sparks 127, Sparks 129, and Sparks 147.
      The highest score ever recorded is a 508
  12. Once scored the samples will be ranked from first to last and printed in the next newsletter. Samples are also typically kept and displayed at the Annual Meeting in the spring for a wider audience to view.

General Notes:

  1. In general, when looking over scores to see how well a sample rated, always look at the crack-out percentage and the grade characteristics to see why some nut samples scored well while others did not.
  2. You are not limited to bringing only one nut sample for evaluation, bring as many as you like.
  3. Black Walnut is not the only type of nut to be evaluated; hickories pecans, English walnut, and hazelnut are also included.
  4. The mathematical symbol < is read "more than" and > is read "less than"