Northwest Michigan apple maturity report – September 21, 2022
Print
EmailReport #3. Apples are maturing and coloring up nicely and growers are eager to get into orchards. Firmness held from last week to this week.
This is the third Apple Maturity Report for the 2022 harvest season for northwest Michigan. Reports are sent out every week (usually 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
Each week, we test apple varieties that are nearing maturity in northwest Michigan. 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
We are still experiencing summer-like weather so far, but the forecast is predicted to change tomorrow, Sept. 22 when the daytime high is predicted to be only 57 degrees Fahrenheit. There is also rain in the forecast for tomorrow, and the upcoming weekend is also supposed to be fairly wet. Daytime temperatures in the foreseeable future will only be in the 50s with overnight temperatures in the high 40s; these conditions will be a big departure from the current warm and sunny conditions so far this September. The forecast is predicting fairly high levels of rainfall accumulation, which may help with apple size, but lots of rain will make it harder for growers to get into orchards for harvest.
General comments
Again, this week, growers are ready to move into harvest. Most early season varieties have been harvested, and growers are starting to spot pick Honeycrisp. We have Honeycrisp apples that are ready to go at the Northwest Michigan Horticultural Research Center (NWMHRC) and others that need more time—as to be expected with this variety. However, when we did our apple testing this week, the spread for maturity with our samples seems to be larger than in past years. Our starch removal values range from 1-6 or 1-7 on Gala, McIntosh, and Honeycrisp. Color continues to improve, but Brix levels seem low in all of the varieties we tested even though our area has not received as much rainfall as other areas in the state.
Reports from across the state are that harvest is still picking out longer than the estimate. As a result of more fruit, bins have been in high demand. We have also heard reports that storage may be an issue for apples with a larger than anticipated apple crop.
Honeycrisp
The most notable change in Honeycrisp this week is the improvement in color since we started testing this variety on Sept. 6. The average color percentage is 70% with a range of 40-90%. Some apples on our trees at the station are looking beautiful. We were pleased to see that there was little change in firmness in Honeycrisp, particularly with the two-pound drop from 19 down to 17 the previous weeks. Starch removal has also improved this week, and our average was 4.08 with a range from 1.5-6. This has jumped by two since last week, which is an indicator that the first pick of Honeycrisp needs to start on many farms. Brix levels have improved, but the average of our samples this week is 12.3% with quite a range of 10.5-18. We typically harvest Honeycrisp around Sept. 25 at the NWMHRC, and this date looks like around the date we will begin in 2022.
|
Honeycrisp maturity sampling for the harvest season |
||||
|
Sample date |
Color % (range) |
Firmness lbs. (range) |
Starch (range) |
Brix % |
|
Sept. 6, 2022 |
44.8% (10-80) |
19.6 (17-23) |
1.3 (1-2) |
10.9 (10-13.6) |
|
Sept. 13, 2022 |
63.825% (25-95) |
17.3 (14-21) |
2.3 (1-6) |
11.3 (9.9-13.5) |
|
Sept. 20, 2022 |
70.1% (40-90) |
17.18 (14.5-20) |
4.08 (1.5-6) |
12.3 (10.5-18.1) |
Gala
Gala color has remained relatively stable from last week, but overall color is good. We did see a slight drop in firmness of Gala, but not notable. Starch removal is up from last week, and the average this week was 1.3 with a big range of 1-8. Brix levels in Gala is also quite low, and the average for this week is 11.7. We tested multiple samples this week, and the size of this variety is still quite small. Rain will improve Gala size.
|
Gala maturity sampling for the harvest season |
||||
|
Sample date |
Color % (range) |
Firmness lbs. (range) |
Starch (range) |
Brix % |
|
Sept. 6, 2022 |
74.125% (15-100) |
22.2 (19-23) |
1.4 (1-5) |
10.5 (8.5-12.5) |
|
Sept. 13, 2022 |
84% (30-100) |
21 (19-23) |
1.8 (1-8) |
10.9 (7.7-13.1) |
|
Sept. 20, 2022 |
88.3% (45-100) |
20.6 (17.5-23) |
3.3 (1-8) |
11.7 (8.5-14.8) |
McIntosh
This variety tends to have good color in northwest Michigan, and again this week color has improved from last week. This week’s Mac samples averaged 84% color compared to 72% last week. Firmness was higher than last week, likely due to differences in testing protocols. However, overall firmness of this softer variety is quite good at this time of the season. Brix levels also remained stable from last week to this week. Starch removal has moved along this week, and again in this variety, we have seen quite the range in maturity.
|
McIntosh maturity sampling for the harvest season |
||||
|
Sample date |
Color % (range) |
Firmness lbs. (range) |
Starch (range) |
Brix % |
|
Sept. 6, 2022 |
55.5% (15-90) |
19.9 (16-23) |
1.9 (1-5) |
10.8 (9.7-13.1) |
|
Sept. 13, 2022 |
72% (40-100) |
17.6 (13-21.5) |
2.4 (1-6) |
11 (10.1-11.6) |
|
Sept. 20, 2022 |
84.3% (60-100) |
18.3 (15-22) |
3.1 (1-7) |
11.8 (8.8-14.7) |
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.
- 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 |
7 |
|
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 |
