Southwest Michigan apple maturity report – September 17, 2026
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EmailJonathon, Golden Delicious, Red Delicious and the remaining Honeycrisp are being harvested this week, while Empire and Jonagold are approaching maturity.
Apple maturity testing will occur weekly for the southwest 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.
Weather
Warm, humid conditions continue across southwest Michigan this Wednesday, Sept. 16, with scattered showers and thunderstorms and highs generally in the 70s. Rain chances should decrease through Thursday, with temperatures reaching the upper 70s before drier conditions arrive for Friday. Friday currently looks like the best harvest window, with partly sunny skies and highs in the mid- to upper 70s. A more organized period of rain and thunderstorms is expected to move into the region Friday night and Saturday, with showers potentially continuing into Sunday.
Overnight temperatures will fall into the upper 50s late this week, providing a greater difference between daytime and nighttime temperatures that should continue to favor red color development in ripening apples. Growers should take advantage of the drier period Friday where possible, as wetter conditions over the weekend may interrupt harvest.
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 1-2 locations in Berrien and Van Buren counties.
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 Southwest Region
Mutsu
Mutsu fruit were sampled from one location in Van Buren County on Monday. Red color is at 1.5%, and background color is green at 4.7. Fruit firmness is at 18.2 lbs of pressure. Starch is an average of 1.4. Sugars are an average of 11.4 Brix. Mutsu is immature this week.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch |
Soluble Solids (Brix) |
|
Sep 14 |
275.2 |
1.5 (0.0–10.0) |
4.7 (4.0–5.0) |
18.2 (16.3–19.6) |
1.4 (1.0–2.0) |
11.4 |
Red Delicious
Red Delicious fruit were sampled from two locations in Berrien and Van Buren counties on Monday. Red color is at 72.4%, and background color is yellow at 2.6. Fruit firmness is at 16.3 lbs of pressure. Starch is an average of 3.4. Sugars are an average of 11.3 Brix. Red Delicious is mature, some blocks have been harvested.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch |
Soluble Solids (Brix) |
|
Sep 14 |
247.0 (235.8–258.2) |
72.4 (69.5–75.2) |
2.6 (2.4–2.7) |
16.3 (16.3–16.4) |
3.4 (3.2–3.6) |
11.3 (11.0–11.5) |
Golden Delicious
Golden Delicious fruit were sampled from one location in Van Buren County on Monday. Red color (blush on Goldens) is at 0%, and background color is green at 4.2. Fruit firmness is at 16.5 lbs of pressure. Starch is an average of 4.6. Sugars are an average of 14.3 Brix. Golden Delicious has reached maturity and harvest is underway.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch |
Soluble Solids (Brix) |
|
Sep 14 |
213.3 |
0 (0-0) |
4.2 (4.0–5.0) |
16.5 (14.4–19.1) |
4.6 (3.0–7.0) |
14.3 |
Evercrisp
Evercrisp fruit were sampled from one location in Van Buren County on Monday. Red color is at 42.5%, and background color is green at 4.5. Fruit firmness is at 23.6 lbs of pressure. Starch is an average of 1.5. Sugars are an average of 14.6 Brix. Evercrisp is immature this week.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch |
Soluble Solids (Brix) |
|
Sep 14 |
247.4 |
42.5 (25.0–70.0) |
4.5 (4.0–5.0) |
23.6 (20.6–25.8) |
1.5 (1.0–3.0) |
14.6 |
Jonathon
Jonathon fruit were sampled from one location in Van Buren county on Monday. Red color is at 75.5%, and background color is green-yellow at 2.7. Fruit firmness is at 15.3 lbs of pressure. Starch is an average of 4.3. Sugars are an average of 12.6 Brix. Jonathon has reached maturity and is being harvested.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch |
Soluble Solids (Brix) |
|
Sep 14 |
191.7 |
75.5 (65.0–85.0) |
2.7 (2.0–3.0) |
15.3 (14.2–17.4) |
4.3 (2.0–6.0) |
12.6 |
Northern Spy
Northern Spy fruit were sampled from one location in Van Buren County on Monday. Red color is at 8.5%, and background color is green at 4.4. Fruit firmness is at 20.7 lbs of pressure. Starch is an average of 1.5. Sugars are an average of 11.4 Brix. Spys are immature this week.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch |
Soluble Solids (Brix) |
|
Sep 14 |
214.6 |
8.5 (0.0–20.0) |
4.4 (4.0–5.0) |
20.7 (18.2–23.5) |
1.5 (1.0–2.0) |
11.4 |
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.
|
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 |
|
Brix Guide |
Low |
Fair |
Good |
Excellent |
|
All varieties |
Less than 11 |
11 |
12 |
13 |
|
Honeycrisp |
Less than 12 |
12 |
12 |
Greater than 14 |
