Grand Rapids area apple maturity report – September 25, 2023
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EmailGala and Honeycrisp harvest are wrapping up this week. More varieties are on the way.
This is the third 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 and Honeycrisp harvests are finishing out this week. Empire, Fuji, Jonagold, and McIntosh are now in line with maturity parameters and should be checked this week. Red Delicious and Ambrosia are both close to full maturity.
- 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
Weather
The Michigan State University Enviroweather station in Sparta did not experience any rainfall in the past week (Sept.18-25), which is helpful for sugar accumulation in the fruits. The Growing Degree Days (GDD) accumulation is 3773.2 for base 42F and 2495.2 base 50F. These numbers have considerably increased with the hot weather late last week.
Variety reports
Ambrosia
Ambrosia apples were collected at one location in Kent County this week. While the starch is still very present and the apples are firm, these apples are close to full maturity. The red coloration is well developed, and the background color is very yellow. The sugar accumulation in these apples is excellent with a range of 12.2-15 and an average of 13.7. Keep in mind that Ambrosia is chilling sensitive and apples harvested at late maturity are more likely to develop soft scald and brown in 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 |
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) |
Empire
Empire apples were sampled at one location in Kent County this week. These apples are mature across all metrics with excellent sugar accumulation.
|
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) |
Idared
Idared apples were sampled at one location in Kent County this week. While the starch clearing and firmness is in line with maturity for this variety, the sugar needs to accumulate further before harvesting.
|
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) |
Fuji
Fuji apples were sampled at three locations this week in Kent County. The firmness, starch clearing, and sugar accumulation are in line with maturity for this variety. The Fuji samples had some water core and white callus development in the seed cavities.
|
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) |
Gala
Gala apples without ReTain were sampled at one location this week in Kent County. The sugar accumulation, firmness, and starch clearing associated with this sample is in line with full maturity. Gala harvest is a priority in the region currently with most growers finishing out Gala harvest this week.
|
Collection Date |
Fruit Weight (g) |
Diameter (mm) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
9/12/23 |
152.1 |
68 |
76.3 |
- |
19.44 |
6.35 |
9.3 |
|
9/18/23 |
160.8 (109-188) |
70.72 (62.7-75.63) |
62 (30-80) |
1.1 (1-2) |
15.53 (12.48-18.52) |
6.3 (3-8) |
9.95 (7.8-11.4) |
|
9/25/23 |
130.8 (90-158) |
64.8 (58.83-69.67) |
69 (30-85) |
1.2 (1-2) |
15.4 (11.4-19.2) |
7 (4-8) |
11.9 (11-13) |
Gala with ReTain
Gala apples with ReTain applied were sampled at one location this week in Kent County. Firmness was very similar to Gala without ReTain. Sugars and starch clearing are slightly less then the Gala without ReTain from the same block.
|
Collection Date |
Fruit Weight (g) |
Diameter (mm) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
9/12/23 |
170.46 |
70.95 |
68.83 |
- |
22.56 |
3.02 |
9.54 |
|
9/18/23 |
157.4 (88-275) |
69.52 (58.14-86.5) |
84.25 (35-95) |
1.45 (1-2) |
18.5 (14.34-24.36) |
5 (1-7) |
10.15 (8.8-11.5) |
|
9/25/23 |
178.6 (152-221) |
73.4 (68.5-79.1) |
59.5 (40-85) |
1.2 (1-2) |
15.3 (12.7-17) |
6.1 (4-7) |
10.67 (7-12) |
Honeycrisp
Honeycrisp apples were collected at one location in Kent County this week. Honeycrisp harvest is well underway this week. Despite the lower-than-expected sugar accumulation, the starch clearing and firmness are moving past peak maturity.
|
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) |
11.11 (7-13.1) |
|
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) |
Jonagold
Jonagold apples were sampled at two locations in Kent County this week. The general maturity level of these two samples, particularly redness development, was very different and associated with crop load and sun exposure. Jonagold apples are in line with all maturity parameters.
|
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) |
Jonathan
Jonathan apples were sampled at one location this week in Kent County. The sugar accumulation is lagging behind the starch clearing, color development, and firmness of the samples.
|
Collection Date |
Fruit Weight (g) |
Diameter (mm) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
9/12/23 |
64.58 |
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) |
McIntosh
McIntosh apples were sampled from two locations this week in Kent County. The strains sampled include RubyMac and standard McIntosh. Starch clearing and sugars are rising while firmness has dropped. McIntosh now falls within all maturity parameters. Please note that overmature starch is 7 for McIntosh and they are currently at an average of 6.25.
|
Collection Date |
Fruit Weight (g) |
Diameter (mm) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
9/12/23 |
116.3 |
66.36 |
90.5 |
- |
26.59 |
4.9 |
9.44 |
|
9/18/23 |
128.95 (96-192) |
68.67 (63.2-95) |
90.5 (65-100) |
1.67 (1-2) |
14.14 (11.99-17.33) |
5.4 (4-7) |
11.71 (9.4-12.6) |
|
9/25/23 |
139.9 (94-181) |
71.4 (61.67-78.96) |
91.5 (80-95) |
1.45 (1-2) |
14.298 (12.37-16.97) |
6.25 (5-8) |
12.03 (10.8-13.1) |
Red Delicious
Red Delicious apples were sampled at two locations in Kent County this week. The color development is well progressed. The firmness is in line with mid-CA storage. The sugar accumulation and starch clearing are very close to full maturity. The Red Delicious samples had some water core and white callus development in the seed cavities.
|
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) |
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 |
