MSU Extension Apples

Apple maturity testing will occur weekly for the west central region beginning now through the end of harvest. Reports will be sent out every week following the Michigan State University Extension fruit team apple maturity calls on Wednesday mornings.

In the west central region, early apple varieties of Paula Red, Premier Honeycrisp, and Minneiska are being harvested this week. Brookfield and Pacific strains of Gala and Honeycrisp are still immature. Fruit size is variable across sites.

Weather over the past few days has been mild with high temperatures in the 70s and lows dipping down into the upper 40s to the low 60s across the region. Storms brought much needed rain in the region on Wednesday, Aug 26. Temperatures will warm up into the upper 70s and low 80s this weekend and going into next week, and lows will be in the 50s and 60s. Cool nighttime temperatures will enhance red color development, which is needed, especially for early apple varieties.

How to read maturity tables

Each week, an apple maturity report will be provided and will include average values for several apple samples for varieties nearing maturity. Maximum and minimum values are included in tables below for the highest and lowest individual fruits evaluated for each, to give a full spectrum of maturity. Samples included in the reports have been untreated with ReTain or Harvista, unless otherwise noted. Samples were collected from 2-5 locations in Oceana County.

For more information about apple maturity testing, review these resources compiled by the MSU Extension tree fruit team.

• Predicted apple harvest dates for 2026 from MSU.
• More information on harvest management tools and timings can be found in this article.
• Guidelines from MSU to check for apple maturity in your own orchard, including specific pressure and starch recommendations by variety.
• New starch charts for evaluating apple maturity in Michigan from Michigan State University
• Predicting apple maturity and starch chart from Cornell University.
• Starch chart for Honeycrisp Apples developed by Washington State University.

Maturity information for the West Central region

Note that apple maturity is occurring earlier than normal this season with variability between orchard blocks and sites. Be sure to test maturity block by block.

Premier Honeycrisp

Fruit were sampled from three locations on Aug. 24 in Oceana County. Individual samples represent fruit closest to maturity or “first pick” fruit in each block. Red color has improved with warm daytime temperatures and cool nighttime temperatures. Background color is yellow green. Starch rating is 6.4. Pressure is 12.1 lbs on average, and Brix are fair at 10.7. Average fruit diameter is 3.1 in.

A note about Premier Honeycrisp: Wait for acceptable varietal flavor and color to develop before picking. Picking fruit and getting it into the market early seems like an edge but will hurt repeat sales of this strain and standard Honeycrisp.

Bitter pit may develop on fruit in some locations. As a reminder, fruit that are high risk or are more susceptible to bitter pit development may be in blocks with younger trees, high-risk rootstocks, high-vigor trees, or low crop loads. Large fruit are also more susceptible to bitter pit development than small fruit. High bitter pit-risk fruit should be cooled quickly to the recommended 38 degrees Fahrenheit storage temperature, as conditioning will exacerbate bitter pit. High risk fruit should be marketed as soon as possible. Fruit intended for longer storage should be pre-conditioned, with recommended conditions of 50 F (room temperature) for 5-7 days.

*Note that only 10 apples from one site were sampled on Aug 18.

Minneiska

Minneiska fruit were sampled at two locations on Aug. 24 in Oceana County. Red color development has improved from last week to 86%. Background color is yellow. Starch is variable depending on site and the average rating is 3.6. Sugar levels are good at 12.0 Brix. Some growers will be harvesting this variety later next week. Average fruit diameter was 2.7 in, and fruit size is variable from site to site.

Gala

Gala fruit were sampled from four locations in Oceana County on Aug. 24. Samples in the table below are for Brookfield and Pacific Gala. Fruit at one site was treated with ReTain. Red color improved from last week and is 84.7%, and background color is yellow at 1.6. Fruit firmness is similar to last week at an average of 21.4 lbs of pressure. Starch is an average of 1.9. Sugars are an average of 10.6 Brix. Average fruit diameter is 2.6 in.

*For August 18-19, fruit weight, red color, and background color were only evaluated at one site. Firmness, starch, and soluble solids were evaluated at four sites in Oceana County.

Honeycrisp

Fruit were sampled from four locations on Aug. 24 in Oceana County. Fruit are still immature. Average pressure is 18.1 lbs, and starch rating was 1.2. Sugars are at 11.3 Brix. Average fruit diameter is 2.9 in.

*For August 18-19, fruit weight, red color, and background color were only evaluated at one site. Firmness, starch, and soluble solids were evaluated at four sites in Oceana County.

September Wonder Fuji

Fruit were sampled from three locations on Aug. 24 and 25 in Oceana County. Average fruit weight was 143.5 kg. Average red color development is 47.6%, and background color is green at 3.9. Pressure is 16.1 lbs, and starch rating is 2.6. Sugars are at 10.7 Brix. Average fruit diameter is 2.7 in.

Apple maturity sampling parameters

• Color % = the visual percentage of red color from 0 to 100; range is of all fruits tested. Indicates surface area covered in red and intensity of red color.
• Background color: 5 = Green, 1 = Yellow; range is of all fruits tested.
• Firmness in pounds pressure = measured with a Güss Fruit Texture Analyzer; range is of all fruits tested.
• Starch For Honeycrisp: will typically be rated using the standard Michigan State University starch scale (1-8). However, a separate starch chart for Honeycrisp Apples developed by Washington State University (scale 1-6) also exists.
• Brix = % sugar measured with Atago PAL-1 Pocket Refractometer

Looking for more? View Michigan State University Extension’s Apple page for regional reports throughout the state and additional resources.

This work is supported by the Crop Protection and Pest Management Program (grant no 2024-70006-43569) from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.