MSU Extension Apples

Apple maturity testing will occur weekly for northwest Michigan 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 northwest region, some growers are just beginning Premier Honeycrisp harvest. Some growers started Minneiska harvest today (Sept. 2), and some are starting later in the week and into the weekend. Apple size is variable across orchards: some blocks have apples with decent size for this time in the season while other orchards have apples on the small size. We have had very little rain in late July and through August, so if growers did not have irrigation, apples are small. The rain this week has been welcomed. McIntosh, Gala, and Honeycrisp samples for this week are immature.

Weather

The northwest region of the state received rainfall on Monday, Aug. 31, which was much needed. The Northwest Michigan Horticulture Research Center (NWMHRC) Enviroweather station recorded just under 1 inch of rain. The region is very dry; we had no rain from July 22 until Aug. 5 when we received 0.68 inches of rain, another 0.3 inches on Aug. 22 and another 0.3 inches on August 29. This last rain event was certainly welcome, and growers are hoping for more to come.

There is a storm front moving across the region this morning, Sept. 2, and there is another 55% chance of rain on Friday, Sept. 4. Temperatures have been hot! The daytime temperature yesterday, Sept. 1, topped out at 88 degrees Fahrenheit, and on Aug. 31 it was 84 F. These hot temperatures were coupled with high humidity. Overnight temperatures were also warm. With the last two night only dipping into the high 60s.

The rain that moved through today reduced the heat, but forecasts are still predicting warm weather with daytime highs in the mid- to high 70s. Warm weather is predicted through the next week.

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 8+ locations in Leelanau County. We also test some apples from Old Mission Peninsula.

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 Northwest Region

Apple maturity is occurring earlier than normal this season in most other growing regions in the state. In northwest Michigan, our predicted harvest dates line up with “normal” harvest dates, but we are seeing variability between orchard blocks and sites. Our numbers are similar to last week’s west central maturity numbers. Be sure to test maturity block by block.

Premier Honeycrisp

Fruit were sampled from one location on September 2 in Leelanau County. Individual samples represent fruit closest to maturity or first pick fruit in each block. The red color was low in this block (43%), but other Premier blocks have excellent color. Starch rating is 4.5. Pressure is 15.9 lbs, and Brix are at 11.

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 F 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.

Minneiska

Minneiska fruit were sampled at one location on September 1. Red color ranges from 40-70% for an average of 57%. The part of the apple with red color does seem particularly bright this year. Background color is yellow. Starch is variable and the average rating is 3.4. Sugar levels are good at 11.7 Brix. Some growers are harvesting this variety now.

Gala

Gala fruit were sampled from five locations on September 1. Red color is 67.2%. Fruit firmness is similar to last week at an average of 22.6 lbs of pressure. Starch is an average of 1.4. Sugars are an average of 9.8 Brix.

Honeycrisp

Fruit were sampled from seven locations on September 1. Fruit are immature. Average pressure is 20.8 lbs, and starch rating was 1.4. Sugars are at 11.1 Brix.

McIntosh

We have few blocks of McIntosh to sample, but we tested one orchard in Leelanau County on September 1. This is an older strain of Mac, and there was little color on the apples so far. These trees are also big, so color will be slow to develop. This variety is 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.