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, some growers are harvesting Jonagold, Rome, Golden Delicious, and Red Delicious this week. EverCrisp and Pink Lady are still immature. Fuji will be mature soon at some sites. Red color, size, and brix have continued to improve.

Weather

Weather was excellent early in the week for harvest, but rainy weather settled in the area on Wednesday, Sept. 20, and Thursday. Cooler temperatures and sunny conditions will follow the rain for the rest of the week and into the weekend with high temperatures in the 60s and low temperatures in the 40s and 50s.

Over the next week, weather will be mostly sunny with slight chances of rain on Wednesday, October 7.

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 1-4 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 for each variety. Young trees are maturing more quickly than older trees, and bitter pit and lenticel breakdown were observed again this week.

Jonagold

Fruit were sampled from one location on September 28 in Oceana County. Average fruit weight improved from last week and is 197 g. Average red color development is 92%, and background color is light green at 1.8. Fruit firmness was higher than last week for this site and is 16.4 lbs, but fruit were treated with ReTain. Starch rating is 6.2. Sugars are similar to last week at 12.6 °Brix. Average fruit diameter was similar to last week at 2.9 in.

*Fruit were sampled from only one location on September 28 and were treated with ReTain.

Rome

Fruit were sampled at one location on September 28 in Oceana County. Average fruit weight was 131 g which was down from the week prior. The difference in fruit weight was due to site. Red color development is almost 100%, and background color is yellow at 1. Pressure is still firm at 22.8 lbs. Starch rating is 3. Sugars are similar to last week at 11.4°Brix, and average fruit diameter is 2.8 in. Fruit are mature and some growers are harvesting this week.

*Fruit was only sampled at 1 location.

Golden Delicious

Fruit were sampled from three locations on September 28 in Oceana County. Average fruit weight is 174 g. A slight blush is present on the sun side of fruit and covers 29% of the surface. Background color is yellow green at 2.8. Pressure is 16.7 lbs, and starch rating is 3.3. Sugars are excellent at 14.2°Brix. Average fruit diameter is 3.0 in, and fruit are mature.

Red Delicious

Fruit were sampled from two locations on September 28 in Oceana County. Average fruit weight was 182 g. Average red color development is 88%, and background color is yellow at 2.2. Pressure is 18.4 lbs, and starch rating is 2.2. Sugars improved slightly and are at 11.8 °Brix. Average fruit diameter is 2.87 in, and fruit are mature at some sites.

Crispin/Mutsu

Fruit were sampled from two locations on September 28 in Oceana County. Average fruit weight was 375 g. The pink blush was similar to last week at 17% on average. Background color is green at 3.6. Pressure is 18.7 lbs, and starch rating is 2.2. Sugars are at 12.5 °Brix. Average fruit diameter is 3.6 in, and fruit are still immature.

Idared

Fruit were sampled from four locations on September 28 in Oceana County. Average fruit weight was 176 g. Average red color development is 75%, and background color is yellow green at 2.7. Pressure is 17.6 lbs, and starch rating is 2.7. Sugars are at 11.7 °Brix. Average fruit diameter is 3.0 in, and fruit are still immature.

Fuji

Fruit were sampled from two locations on September 28 in Oceana County. Average fruit weight was 197 g. Average red color development is 74%, and background color is green at 2.9. Pressure is 17.7 lbs, and starch rating is 2.8. Sugars are at 12.4 °Brix. Average fruit diameter is 3.0 in, and fruit are still immature.

EverCrisp

Fruit were sampled from two locations on September 28 in Oceana County. Average fruit weight was 205 g. Average red color development is 67%, and background color is green at 3.1. Pressure is 23 lbs, and starch rating is 2.4. Sugars are excellent at 13.9 °Brix. Average fruit diameter is 3.1 in, and fruit are still immature.

Pink Lady

Fruit were sampled from one location on September 28 in Oceana County. Average fruit weight was 170 g. Average red color development is 48%, and background color is green at 2.7. Pressure is 20.1 lbs, and starch rating is 2.5. Sugars are excellent at 13.4 °Brix. Average fruit diameter is 3.1 in, and fruit are still immature.

*Fruit were sampled from one location.

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.