Grand Rapids area apple maturity report – October 4, 2023
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EmailHoneycrisp harvest is wrapping up. Many other varieties are currently mature.
This is the fourth Grand Rapids, Michigan, area apple maturity report for the 2023 harvest season. Reports are sent out every week (usually on Wednesdays), following the Michigan State University Extension fruit team apple maturity calls on Wednesday morning.
Gala harvest has finished in the area and Honeycrisp harvest is almost over. McIntosh strains, Red Delicious and Empire are being harvested this week. Ambrosia, Golden Delicious, Fuji, Jonagold, Jonathan and Spy apples are also currently mature. Idared and Mutsu apples are close to maturity.
Watercore has been seen across Jonathan, Red Delicious, Ambrosia and Fuji samples in this area. Please keep watercore presence in mind for long-term storage decisions. Callus tissue in the seed cavity has been seen in Red Delicious, Fuji and Ambrosia apples and can be easily confused with moldy core. This resource on callus tissue has more information.
- Predicted apple harvest dates for 2023 from MSU Extension.
- More information on harvest management tools and timings can be found in this article.
- Guidelines from MSU Extension to check for apple maturity in your own orchard, including specific pressure and starch recommendations by variety.
- Predicting apple maturity and starch chart from Cornell University.
- Starch chart for Honeycrisp apples developed by Washington State University.
How to read the maturity tables
Each week, we test apple varieties that are nearing maturity in the Grand Rapids region. We are reporting average values for several samples for each variety. Maximum and minimum values are included for the highest and lowest individual fruits evaluated for each to give a full spectrum of the maturity.
Updates for this week
The Grand Rapids area experienced another warm and sunny week with minimum daily temperatures ranging from 51.2-59.2 degrees Fahrenheit and maximum daily temperatures ranging from 62.8-83.7 F at the Michigan State University Enviroweather Station in Sparta. These high temperatures have continued to push growing degree days (GDD) along with base 42 F GDD at 3,968.4 and base 50 F GDD at 2,619.1 as of Tuesday, Oct. 3. The Michigan State University Enviroweather Station in Sparta collected 0.07 inches of rain in the last week.
The Sparta area is expecting rain Wednesday night into Thursday. Please keep in mind that this can negatively impact sugars in the fruit. If rainfall exceeds 2 inches, consider reapplying fungicides to limit storage rot issues.
The temperatures will decline following this rain event with lows in the high 30s this weekend. It is not predicted to approach frost temperatures.
Ambrosia
Ambrosia apples were sampled at two locations in Kent County this week. These apples are mature according to the starch clearing, firmness and sugar accumulation. The red coloration is very well developed at this point. The sugar accumulation is excellent with an average of 14.36 brix. The taste of these samples is also excellent.
|
Collection Date |
Fruit Weight (g) |
Diameter (mm) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
9/12/23 |
118.5 |
62.45 |
48 |
|
26.82 |
1.2 |
9.54 |
|
9/18/23 |
164.2 (121-216) |
70.63 (62.5-78.26) |
75.5 (50-90) |
1 (1-1) |
19.98 (17.18-23.1) |
1.4 (1-3) |
11.23 (9.5-12.3) |
|
9/25/23 |
125.1 (105-147) |
62.87 (58.7-68.02) |
68 (45-85) |
1.8 (1-3) |
23.009 (19-28.796) |
1.7 (1-2) |
13.7 (12.2-15) |
|
10/2/23 |
206.05 (124-310) |
75.3725 (61.73-90.19) |
75.75 (90-65) |
1.05 (1-2) |
17.731 (14.67-22.26) |
4.2 (3-6) |
14.36 (13.8-15) |
Empire
Empire apples were sampled at one location in Kent County this week at a different block from last week. While the sugar accumulation in this sample is lower than target values (greater than 11), the firmness and starch clearing are in line with maturity for this variety. Empires are currently being harvested in this area.
|
Collection Date |
Fruit Weight (g) |
Diameter (mm) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
9/25/23 |
184.9 (134-207) |
76.4 (72.58-79.48) |
92 (85-95) |
2.2 (1-3) |
13.2 (13.1-20.2) |
3.6 (3-4) |
13.58 (12.4-16) |
|
10/2/23 |
154.6 (127-190) |
70.788 (65.41-77.04) |
72.5 (60-85) |
1.7 (1-3) |
15.443 (13.109-17.06) |
5.5 (5-6) |
10.56 (9.8-11) |
Idared
Idared apples were sampled at two locations in Kent County this week. The values have not shifted significantly from last week. Sugars are still low with an average of 9.51 while starch clearing and firmness are in line with maturity for this variety.
|
Collection Date |
Fruit Weight (g) |
Diameter (mm) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
9/25/23 |
173.1 (136-204) |
75.44 (79.59-68.23) |
61 (35-80) |
2.8 (2-3) |
14.7 (12.89-19.55) |
2.8 (2-4) |
9.48 (9-10.2) |
|
10/2/23 |
181.2 (132-259) |
76.371 (66.1-89.5) |
67.75 (45-90) |
1.85 (1-3) |
14.255 (12.48-16.55) |
3.55 (2-7) |
9.51 (8.2-11) |
Golden Delicious
Golden Delicious apples were sampled at two locations this week in Kent County. These samples are in line with maturity values for this variety. The firmness at 15.91 pounds is well suited for mid-length controlled atmosphere (CA) storage.
|
Collection Date |
Fruit Weight (g) |
Diameter (mm) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
10/2/23 |
197.9 (113-288) |
74.852 (63.44-85.72) |
3.5 (0-7) |
1.7 (1-2) |
15.9185 (13.23-18.89) |
5.05 (4-7) |
12.33 (10.2-14) |
Fuji
Fuji apples were sampled at three locations this week in Kent County. The sugar accumulation, starch and firmness values are in line with maturity for this variety. Be aware of watercore development in this variety, which can limit the storage capacity of Fuji apples.
|
Collection Date |
Fruit Weight (g) |
Diameter (mm) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
9/12/23 |
157.3 |
74.1 |
52.5 |
|
20.93 |
3.4 |
8.17 |
|
9/18/23 |
181.15 (122-236) |
75.141 (67.57-80.19) |
72.25 (30-90) |
1.725 (1-2) |
15.88 (11.75-22.17) |
4.9 (1-8) |
10.55 (8.7-12.4) |
|
9/25/23 |
179.57 (93-288) |
73.2 (60.43-89.17) |
73 (35-90) |
2.3 (1-3) |
16.7 (10.9-25.6) |
4 (1-8) |
12.12 (10-13) |
|
10/2/23 |
154.7 (83-244) |
69.983 (58.48-80.47) |
58.3 (25-90) |
1.83 (1-3) |
16.97 (11.6-23.69) |
4.87(2-8) |
12.24 (9-15.1) |
Honeycrisp
Honeycrisp apples were sampled at one location in Kent County this week. The majority of Honeycrisp apples have been harvested in the area. The apples sampled this week are moving into over-maturity; starches are completely cleared and firmness has dropped below short-CA recommendations for this variety.
|
Collection Date |
Fruit Weight (g) |
Diameter (mm) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
9/12/23 |
182.7 |
74.1 |
74.75 |
|
17.9 |
7.4 |
10.15 |
|
9/18/23 |
161.6 (132-289) |
72.65 (68.7-89.6) |
75.25 (30-95) |
1.8 (1-3) |
13.12 (11.19-14.56) |
7.2 (6-8) |
10.55 (9.7-13.6) |
|
9/25/23 |
153.2 (114-186) |
72.43 (66.55-77.55) |
71 (30-90) |
1.8 (1-3) |
14.6 (12.5-17.5) |
7.3 (7-8) |
11.7 (11-12.2) |
|
10/2/23 |
265.3 (226-328) |
85 (79.92-89.73) |
61.1 (85-35) |
1.1 (2-1) |
13.67 (11.61-15.479) |
8 (8-8) |
11.7 (11-12) |
Jonagold
Jonagold apples were sampled at two locations in Kent County this week. While the sugar accumulation and firmness are not deeply changed from last week to this week, the starch clearing has progressed towards over-maturity. Jonagold coloring and maturity is heavily impacted by sun exposure and cropload. Please keep this in mind when making harvesting decisions; the two samples this week had very different maturity progressions based on these factors.
|
Collection Date |
Fruit Weight (g) |
Diameter (mm) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
9/25/23 |
247.6 (129-342) |
81.2 (65.8-90.21) |
46.2 (12-85) |
2.1 (1-3) |
15.4 (13.28-19.67) |
5.25 (3-8) |
11.59 (10-13) |
|
10/2/23 |
241.15 (139-284) |
79.9805 (68.72-89.15) |
41 (5-85) |
1.45 (1-3) |
15.005 (12.94-18.19) |
7.25 (6-8) |
11.42 (10-13) |
Jonathan
Jonathan apples were sampled from two locations in Kent County this week. These apples are currently mature and almost overmature. While the sugar accumulation is good with an average of 12.72, the starch clearing is indicative of over-maturity with an average of 7.35. The firmness is in line with short CA storage.
|
Collection Date |
Fruit Weight (g) |
Diameter (mm) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
9/12/23 |
105.7 |
64.58 |
95.5 |
|
21.05 |
4.4 |
8.61 |
|
9/18/23 |
213.75 (91-333) |
77.11 (60.44-92.29) |
83 (20-100) |
1.45 (1-2) |
15.53 (13.9-18.49) |
3.35 (2-7) |
11.11 (7-13.1) |
|
9/25/23 |
99.4 (86-125) |
64.89 (61.61-68.78) |
95.5 (90-100) |
1 (1-1) |
15.2 (13.47-16.98) |
7.1 (6-8) |
10.74 (10-11.9) |
|
10/2/23 |
130.25 (80-198) |
69.509 (59.48-81.22) |
92.5 (85-100) |
1 (1-1) |
14.135 (12.84-16.7) |
7.35 (7-8) |
12.72 (11-14) |
Mutsu
Mutsu apples were sampled at two locations in Kent County this week. These apples had excellent sizing and are close to mature. The sugar accumulations are currently fair to good at an average of 11.47 brix. The firmness is still fairly high at an average of 17.82 pounds.
|
Collection Date |
Fruit Weight (g) |
Diameter (mm) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
10/2/23 |
352.95 (171-503) |
89.7325 (73.72-103.14)) |
2 (0-15) |
1.8 (1-2) |
17.82 (14.13-20.17) |
3.85 (3-7) |
11.47 (10.5-12.5) |
Red Delicious
Red Delicious apples were sampled at two locations in Kent County this week. This variety is currently mature. While firmness has decreased to an average of 15.3 pounds, the starch clearing and sugar accumulation has not significantly progressed since last week.
|
Collection Date |
Fruit Weight (g) |
Diameter (mm) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
9/18/23 |
154.8 (117-175) |
69.63 (62.46- 74.32) |
88 (75-100) |
1.4 (1-2) |
17.56 (16.13-19.25) |
2.1 (1-4) |
10.56 (9.9-12.2) |
|
9/25/23 |
188.07 (120-258) |
72.3 (63.4-81.25) |
91.4 (75-95) |
1.1 (1-2) |
17.12 (13.98-19.97) |
2.38 (2-3) |
11.01 (10.1-12.1) |
|
10/2/23 |
260.7 (202-390) |
81.905 (74.66-94.59) |
88.25 (75-95) |
1.05 (1-2) |
15.3015 (13.53-18.28) |
2.95 (2-4) |
11.46 (10.2-13) |
Spy
Spy apples were collected at one location in Kent County this week. While the sugar accumulation is currently low at an average of 10.12 brix, the firmness and starch clearing are well progressed and close to over-maturity.
|
Collection Date |
Fruit Weight (g) |
Diameter (mm) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
10/2/23 |
163.9 (105-219) |
74.81 (64.46-80.99) |
57 (35-80) |
1.7 (1-2) |
15.51 (13.64-18.31) |
7.2 (6-8) |
10.12 (8.8-11) |
Apple maturity sampling parameters
- % fruits with internal ethylene over 0.2 ppm = indicates when ethylene begins to influence fruit ripening and it cannot be held back easily after this is reached.
- Color % = the visual percentage of red color from 0 to 100; range is of all fruits tested
- 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: 1 = all starch, 8 = No starch; range is of all fruits tested. Using Cornell Starch Iodine Index Chart.
- 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.
|
Brix Guide |
Low |
Fair |
Good |
Excellent |
|---|---|---|---|---|
|
All varieties |
Less than 11 |
11 |
12 |
13 |
|
Honeycrisp |
Less than 12 |
12 |
12 |
Greater than 14 |
|
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 |
