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 Gala and September Wonder Fuji this week. Honeycrisp maturity changed rapidly from last week, and fruit at all sites we tested were mature. Jonagold was mature at some sites and could be harvested for long-term storage if needed.

Fruit size and red color improved from last week for many varieties due to rain and cooler nighttime temperatures over the weekend. Apple size continues to be variable across orchards, and fruit size is smaller particularly in non-irrigated blocks. The recent rainfall should help improve fruit size.

Empire are still immature. Use preharvest management tools as needed to harvest fruit in a timely manner.

Weather

Storms brought rain across the region over the Labor Day weekend. Over the past week, the Hart Enviroweather station recorded 0.74 inches of rain on since September 3. Storm systems brought cooler temperatures with highs in the 70s and lows in the 50s. Another storm system brought warmer overnight temperatures on September 9 and rain during the day.

Cooler temperatures will come the rest of the week with highs in the 70s and lows in the 50s.

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 2-7 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 this week.

Gala

Gala fruit were sampled from five locations in Oceana County on September 8. Some growers have begun harvested Gala, especially on younger blocks. Samples in the table below are for Brookfield, Gale, and Pacific Gala. Average red color was similar to last week 84.2% from sampled apples, but generally, red color and fruit size improved notably from last week. Background color is yellow at 1.1. Fruit firmness is lower than last week with an average of 17.8 lbs of pressure. Starch is an average of 3.9, and fruit are mature. Sugars improved with an average of 11.6 Brix. Average fruit diameter is 2.8 inches.

*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 six locations on September 8 in Oceana County. Fruit were mature at all sites which was a notable change from last week. Red color development improved and is 74.7%, and background color is 3.0. Average pressure was lower from last week and is 15.1 lbs, and average starch rating is 5.9. For these average numbers, fruit could be harvested for short-term storage according to the table below. Sugars improved from last week and are excellent at an average of 13.3 Brix. Average fruit diameter is 3.2 inches. Some bitter pit is developing on trees, especially at sites with large fruit size. Lenticel breakdown was also observed on some fruit.

*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 one location on September 9 in Oceana County. Average fruit weight was 146 kg which is lower than last week; however, this is due to site-to-site variation and smaller fruit at this site. Average red color development is 38.5, and background color is green at 4.0. Pressure is lower than last week at 15.5 lbs, and starch rating is 4.7. Sugars are similar to last week at 11 Brix. Average fruit diameter is 2.7 inches. Fruit at this site are still immature. Fruit at another site were mature and were harvested this week.

Jonagold

Fruit were sampled from five locations on September 8 in Oceana County. Average fruit weight improved from last week and is 194 kg. Average red color development is 86%, and background color is green at 3.9. Fruit firmness was lower than last week at 17.2 lbs, and starch rating is 2.7. Sugars are at 12.0 Brix. Average fruit diameter is 2.9 inches.

Empire

Fruit were sampled from two locations on September 8 in Oceana County. Average fruit weight was 130 kg, and fruit size is still small. Average red color development is 68%, and background color is green at 3.8. Pressure is 18.3 lbs, and starch rating is the same as last week at 1.4. Sugars improved and are at 11.1 °Brix. Average fruit diameter is 2.7 inches, and fruit are still immature.

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.