Southwest Michigan apple maturity report – August 31, 2022
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EmailApples being harvested this week include Jonathan for processing and McIntosh, and finishing up early season Honeycrisp strains.
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.
- Predicted apple harvest dates for 2022 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.
- 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
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) |
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.