Southwest Michigan apple maturity report – August 31, 2022

Apples being harvested this week include Jonathan for processing and McIntosh, and finishing up early season Honeycrisp strains.

Gala apples.
Gala is the next major variety to be harvested in Southwest Michigan. Photo by Bill Shane, MSU Extension.

This is our weekly southwest region apple maturity reports. Reports are sent out on Wednesdays, following the Michigan State University Extension fruit team apple maturity calls on Wednesday morning. 

How to read the maturity tables 

We test apple varieties that are nearing maturity in the southwest Michigan area, with focus on Berrien County. We are reporting average values for firmness, starch index and brix for several samples for each variety. Maximum and minimum values are included for the highest and lowest average for individual orchards.

Gala (Main season types)

Gala internal maturity has jumped since last week with some locations having some fruit in the mature zone.  Fruit firmness is still excellent—the predicted central Berrien County harvest date is Sept. 6.

Collection Date

Red Color (%) 

Firmness (lbs) 

Starch (1-6) 

Soluble Solids (°Brix) 

Aug 22 

60 (55-65)

22.3 (21-24)

1.1 (1-1.6)

10.2 (9.4-11.3)

Aug 29

82 (62-95) 

21.1 (20-23) 

2.8 (1.6-4.4) 

11.2 (10.2-12.4) 

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

Early Fuji 

Strains tested include September Wonder, Daybreak and Nickell. Red color hasn’t improved significantly from last week.  Internal starch conversion has creeped up to 3.8., well above the mature threshold of 3. Firmness has dropped nearly 2 lbs since last week and Brix has gone up about 1%.  The storage life of early Fuji strains is generally less than standard Fuji. 

Collection Date

Red Color (%) 

Firmness (lbs) 

Starch (1-6) 

Soluble Solids (°Brix) 

Aug 22 

47 (40-65) 

18.6 (18.3-19 

3.3 (3.0-3.6) 

11.2 (10.1-11.8

Aug 29

39 (30-50) 

16.4 (16-17.2)

3.8 (3.4-4)

12.1 (10.4-13.3)

Mac 

Strains tested include Ruby and Linda Mac. Starch indices are still in the immature range (below 5). Fruit firmness dropped about 1 lb since last week. Harvest can be delayed some, but not too long, based on these samples. 

Collection Date

Red Color (%) 

Firmness (lbs) 

Starch (1-6) 

Soluble Solids (°Brix) 

Aug 22 

54 (40-75) 

17 (16-18) 

2.4 (1-3) 

11.6 (10.8-12.4)

Aug 29

54 (30-73) 

16.1 (15.2-17)

3.4 (3-4.2)

12.2 (11-13.7)

Jonagold

The first samples were taken this week.  Fruit background color is still relatively green. Starch conversion has begun.  The fruit are still relatively firm and so the harvest can be delayed until the fruit reaches the 3.5 point starch conversion level considered mature, assuming the fruit will be used for fresh market. 

Collection Date

Red Color (%) 

Firmness (lbs) 

Starch (1-6) 

Soluble Solids (°Brix) 

Aug 29

N/A

19.4 (18.2-21)

2 (2-2)

12 (11.7-12.2)

 

Quick looks (small sample size) 

Honeycrisp has average firmness of 17.1 lbs, starch testing 1.3 (still immature), and Brix of 11.8.  Empire is testing 20.5 lbs firmness, starch conversion of 2.0 (still immature) and brix of 11.1.

Apple maturity sampling parameters 

  • Color % = the visual percentage of red color (blush) from 0 to 100; range is of all fruits tested. 
  • Firmness in pounds pressure = measured with a FT Penetrometer; range is of all fruits tested. 
  • Starch: 1 = all starch, 8 = No starch; range is of all fruits tested. Using Cornell Starch Iodine Index Chart.  
  • Starch For Honeycrisp: a separate starch chart for Honeycrisp Apples developed by Washington State University (scale 1-6). 
  • Brix = % sugar measured with Atago PAL-1 Pocket Refractometer 

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

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

Variety

Firmness (pounds)*

Starch Index*

Short CA

Mid-CA

Long CA

Mature

Over mature

McIntosh

14

15

16

5

7

Gala

16

17

18

3

6

Honeycrisp

15

16

17

3.5

6

Empire

14

15

16

3.5

6

Early Fuji

16

17

18

3

7

Jonagold

15

16

17

3.5

5.5

Jonathan

14

15

16

3.5

5.5

Golden Delicious

15

16

17

3

6.5

Red Delicious

16

17

18

2.5

6

Idared

14

15

16

3.5

6

Fuji

16

17

18

3

7

Rome

15

16

18

3

5.5

Normal and predicted 2022 peak harvest dates for apple varieties in central Berrien County in southwest Michigan based on weather data at the Southwest Michigan Research and Extension Center, Benton Harbor, MI. 

Variety

Normal date

2022 Predicted peak harvest date 

Zestar

22-Aug

20-Aug

Paula Red

22-Aug

20-Aug

Gingergold

20-Aug

18-Aug

Gala

8-Sep

6-Sep

McIntosh

10-Sep

8-Sep

Early Fuji 

3-Sep

1-Sep

Honeycrisp

13-Sep

11-Sep

Empire

19-Sep

18-Sep

Jonathan

22-Sep

21-Sep

Jonagold

22-Sep

21-Sep

Fuji

25-Sep

24-Sep

Golden Delicious

25-Sep

24-Sep

Red Delicious

28-Sep

29-Sep

Ida Red

5-Oct

6-Oct

Rome

5-Oct

6-Oct

Braeburn

20-Oct

21-Oct

Goldrush

26-Oct

27-Oct

Predictions are for the first significant harvest date rather than peak harvest. Also note that the normal harvest date for Fuji is approximately three weeks ahead of the normal date given in previous years reports. Newer strains of Fuji have much earlier and more extensive red blush development than older strains. In the past harvest of Fuji was delayed past optimum internal maturity to wait for better blush development. This delay has resulted in increased storage problems, including watercore and internal browning.  

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