Southwest Michigan apple maturity report – August 27, 2025

Cooler temperatures and sunshine have enhanced red color in ripening apples as Gala, Honey Crisp and Macintosh head towards harvest.

Several apples in a tray cut in half and treated with iodine to stain the starch blue.
Starch test of Empire apples testing for maturity. Apples were cut in half and treated with iodine to stain starch blue. As fruit matures and the starch is converted to sugar, flesh stays unstained (cream-colored). In general, apples with more than approximately 30% unstained area are considered mature. Photo by Winter Krajci.

This is our weekly southwest region apple maturity report. Reports are sent out following the Michigan State University Extension fruit team apple maturity calls on Wednesday morning. View Michigan State University (MSU) Extension’s Apple Maturity page for regional reports throughout the state and additional resources.

Overview 

Crop loads in southwest Michigan are generally good, with some light crops due to some poor pollination conditions during bloom, hail damage and ongoing dry conditions. In general, apples in central southwest Michigan are predicted to mature a few days to a week ahead of normal due to warm temperatures in the month after bloom. Blocks with light crop loads will mature three or four days sooner than the predicted harvest dates while heavy crop loads will mature up to a week later than the predicted dates.

The Michigan apple crop forecast for 2025 is above average at 30 million bushels, as given in the USApple Crop Outlook on Aug. 15. The following tables give a summary for select varieties that are currently nearing harvest sampled from three orchards in Berrien County. 

Gala (Standard) 

Gala shows a range of maturities, with starch tests primarily indicating a score of 2 (near the optimal level for controlled atmosphere [CA] storage) but not reaching a fully mature level of 3. The firmness tests indicate fruit are within the appropriate range for long to mid-term CA storage. The predicted harvest date for 2025 for central Berrien County is now Sept. 5 (updated from last week’s prediction due to current data). The Sept. 5 harvest is approximately one week ahead of the historical harvest date for the region.

Collection Date 

Red Color (%)

Firmness (lbs) 

Starch (1-8) 

Soluble Solids (°Brix) 

Aug. 25 

71.5 (40-95) 

17.7 (14 – 23.5) 

1.7 (1-2) 

9.5 (8.6-10.5) 

*Starch values according to the 1-8 scale developed by Cornell University. 

Mac 

Strains tested include Ruby and Linda Mac. Starch indices are in the immature range, below the mature threshold of 5. Fruit firmness is looking promising for storage at this point; however, fruit will continue to soften as we near harvest so keeping a close eye on firmness as starches continue to develop will be important for making storage decisions. Predicted harvest date for central Berrien County in 2025 is Sept. 2, about a week earlier than historical harvest dates.

Collection Date 

Red Color (%) 

Firmness (lbs) 

Starch (1-8) 

Soluble Solids (°Brix) 

Aug. 25 

39 (25-60) 

15.8 (13-19.5) 

2.8 (2-3) 

 9.9 (9.7-10.1)

Honeycrisp 

This variety is averaging 2.7 for the starch test—the mature starch threshold is 3.5. The current average firmness reading is 15.7 pounds, which is within range for long-term CA target value of 16 pounds. The predicted peak harvest date for central Berrien County is around Sept. 5, updated from last week’s estimate based on current data. Like other varieties, Honeycrisp stores better if harvested early in the maturation process. See “Comprehensive Honeycrisp harvest and storage recommendations” by Michigan State University (MSU) researcher Randy Beaudry for Honeycrisp harvest and storage recommendations. 

Collection Date 

Red Color (%) 

Firmness (lbs) 

Starch (1-8) 

Soluble Solids (Brix) 

Aug. 25 

65.5 (40-90) 

15.7 (11.5-18.8) 

2.7 (1-5) 

10.4 (10.3-10.5)

*Starch values according to the 1-8 scale developed by Cornell University. 

Empire

This variety is averaging 1.6 for the starch test—the mature starch threshold is 3.5. The current average firmness reading is 20.9 pounds, compared to the desired minimum firmness for long-term CA storage of 16 pounds. The predicted peak harvest date for central Berrien County for fresh market CA storage is Sept. 16, perhaps a few days earlier than historical harvest dates. Early pickings could be recommended for taffy apples.

Collection Date 

Red Color (%)

Firmness (lbs) 

Starch (1-8) 

Soluble Solids (Brix) 

Aug. 25 

70 (50-90) 

20.9 (17.8-24.5) 

1.6 (1-2) 

9.6

*Starch values according to the 1-8 scale developed by Cornell University. 

Jonagold

This variety is averaging 1 for the starch test—the mature starch threshold for fresh market is 3.5. The current average firmness reading is 17.9 pounds, the desired minimum firmness for long-term CA storage is 16 pounds. Fruit may be on the soft side so keep a close eye. Plant growth regulator applications (for example, Retain) were applied last week in some of the sampled Jonagolds. The predicted peak harvest date for central Berrien County is Sept. 19. Early pickings could be recommended for taffy apples.

Collection Date 

Red Color (%) 

Firmness (lbs) 

Starch (1-8) 

Soluble Solids (Brix) 

Aug. 25 

14.9 (0-60) 

17.9 (15.3-21.5) 

1

9.75 (9.4-10.1)

*Starch values according to the 1-8 scale developed by Cornell University. 

Apple maturity sampling parameters 

  • Color % = the visual percentage of red color (blush) from 0 to 100; range shown is for the orchard averages. 
  • Firmness in lbs pressure, skin off, as measured with a FT Penetrometer; range is for the site averages. 
  • Starch: 1 = all starch (solid blue staining), 8 = no starch (white); range is for the site averages. Starch Iodine Index Chart.
  • Brix = % sugar measured with Atago PAL-1 Pocket Refractometer 

Suggested firmness and starch index levels for long-term and shorter-term controlled atmosphere (CA) storage by variety. 

Variety 

Firmness (lbs)* 

Starch Index* 

Short CA 

Mid-CA 

Long CA 

Mature 

Over mature 

McIntosh 

14 

15 

16 

Gala 

16 

17 

18 

Honeycrisp 

15 

16 

17 

3.5 

Empire 

14 

15 

16 

3.5 

Early Fuji 

16 

17 

18 

Jonagold 

15 

16 

17 

3.5 

5.5 

Jonathan 

14 

15 

16 

3.5 

5.5 

Golden Delicious 

15 

16 

17 

6.5 

Red Delicious 

16 

17 

18 

2.5 

Idared 

14 

15 

16 

3.5 

Fuji 

16 

17 

18 

Rome 

15 

16 

18 

5.5 

Braeburn 

16 

17 

18 

2.5 

See the following helpful resources for more information: 

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