Northwest Michigan apple maturity report – September 28, 2023
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EmailHoneycrisp harvest is ongoing across the region and fruit is testing mature. Growers will move to Gala upon Honeycrisp harvest completion.
This is the fourth apple maturity report for 2023 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.
Growers are working through Honeycrisp block, and the weather has been favorable for harvesting fruit. We have tested hundreds of Honeycrisp for research projects over the past week, and all apples are testing mature at this time. Brix levels across the board have been lower in this variety, but this measurement does vary between blocks where entire orchards test higher than other orchards. There seems to be little variability in brix measurements from apples in the same block. Starch removal readings are high, and most fruit we tested from sites in Leelanau, Benzie and Grand Traverse counties and at the Northwest Michigan Horticulture Research Center are testing in the 6-8 range. Almost every apple we collected from the Northwest Michigan Horticulture Research Center tested as an 8 based on the starch removal charts.
Honeycrisp fruit is juicy, and firmness is testing around the 17 range, but we are seeing outliers above and below that measurement. Color has improved, but our color at the Northwest Michigan Horticulture Research Center is not as good as we would have expected. Growers that used mylar this season have markedly better color than orchards where no reflective material was used. From this year’s situation and rapid increases in early maturity, growers need to consider adopting ReTain or Harvista into their programs in future seasons. These materials are making a big difference in orchards where they have been used.
Growers are concentrating on Honeycrisp, but Gala is starting to mature, and growers will be going after that variety soon. Gala’s color is looking excellent in most blocks, and size is variable between blocks. Other later varieties are coloring and starting to mature. Fuji and Evercrisp at the Northwest Michigan Horticulture Research Center are starting to ripen but still have time before they are considered mature.
Weather
For those of us that are not ready to let go of summer, this past week and the coming week is for us. The weather has been warmer than seasonable for this time of year, and the forecast is predicting temperatures into the 80s over the weekend. Weather will continue to be warm until the end of next week when cooler and potentially wetter weather will move into the state. Nighttime temperatures are predicted to cool but only into the mid- and high 50s for the remainder of the week and into the weekend and start of next week. These conditions are not optimal for color improvement as many growers have been letting fruit hang to improve color in Honeycrisp and Gala.
How to read 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 maturity. All samples included in the reports have been untreated with ReTain or Harvista, unless otherwise noted.
- 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 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.
Jonagold
There are not as many Jonagold blocks across the region as in years past. This variety is testing higher in brix than some other varieties this season. Color from our single sample shows a fairly big range: 50-100%. Growers also echo seeing a wide range in color in their orchards. Firmness and starch are also variable in our one sample of Jonagold. Growers with other varieties will focus harvest efforts there before jumping into Jonagold.
|
Jonagold maturity sampling for the harvest season |
||||
|---|---|---|---|---|
|
Sample date |
Color % (range) |
Firmness lbs. (range) |
Starch (range) |
Brix % |
|
Sept. 26, 2023 |
78% (50-100) |
17.5 (14-20) |
5.0 (3-7) |
12.6 (10.6-14.3) |
Gala
Starch removal readings are starting to register mature in Gala. We started the season on Sept. 5 with a range in starch from 1-2, and this remained constant for the second week of testing. On Sept. 19, we saw the range increase from 2-7, and this week, we also see a similar range of measurements. Brix has remained consistent for the entirety of testing of Gala fruit: 10-11.7 for the past five weeks. Color has also been consistent but the ranges have tightened since the first week of testing. Firmness is another parameter that has not changed much over the five weeks. We started the season with an average firmness of 21.8 pounds, and this week we had an average of 19.4 pounds. These readings are good news as the fruit are still firm. Growers are starting to move into Gala blocks or will move into Gala as soon as their Honeycrisp blocks are harvested.
|
Gala maturity sampling for the harvest season |
||||
|---|---|---|---|---|
|
Sample date |
Color % (range) |
Firmness lbs. (range) |
Starch (range) |
Brix % |
|
Sept. 5, 2023 |
72% (5-100) |
21.8 (19-23) |
1.4 (1-2) |
10.6 (8.6-13.6) |
|
Sept. 12, 2023 |
80.5% (30-100) |
20.4 (17-21) |
2.4 (1-6) |
10.6 (8.6-13.7) |
|
Sept. 19, 2023 |
92.3% (70-100) |
21.1 (17.5-23) |
3.3 (2-7) |
12.1 (9.1-14.8) |
|
Sept. 26, 2023 |
89% (60-100) |
19.4 (16.5-22.5) |
5.2 (2-8) |
11.7 (9.7-14.8) |
Apple maturity sampling parameters
- Ethylene (% 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. 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: 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.
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Suggested firmness and starch index levels for long-term and shorter-term controlled atmosphere (CA) storage by variety. |
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|---|---|---|---|---|---|
|
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 |
