Grand Rapids area apple maturity report – August 17, 2022
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EmailEarly varieties are nearing maturity in the Grand Rapids area.
This is the third maturity apple maturity report for 2022. Reports are sent out every week (usually on Wednesdays), following the Michigan State University Extension fruit team apple maturity calls on Wednesday morning.
This week in the Grand Rapids, Michigan, area, early varieties are showing increasing signs of maturity. First picks are likely to start at the end of the week or early next week in Premier Honeycrisp, Paula Red, Ginger Gold and Zestar.
Weather couldn’t have been better this week! Temperatures were much more moderate, with highs in 70s (degrees Fahrenheit) all week, and overnight lows in the 50s. As of Aug. 8, the Michigan State University Sparta Enviroweather station has accumulated 2820.4-degree days base 42 F (DD42). This is slightly above average, which is 2705.6 DD42, and approximately five days ahead of normal. Saturday’s rainfall was much needed and couldn’t have come at a better time. Accumulation was significant, with 1-2 inches recorded at most locations.
Expect warmer conditions this week. High temperatures will be in the 80s with lows in the upper 50s. Thunderstorms are possible over the weekend, with a potential 0.5 inch of rainfall.
How to read maturity tables
Each week, we test apple varieties that are nearing maturity in the Grand Rapids area. 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.
- 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.
Zestar
Red color very good in most places, background color is still slightly green. Flavor beginning to develop, and starch clearing evident. A little more time is needed for this variety to reach maturity. Picking by the end of the week or early next week
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Ethylene (% >0.2ppm) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Aug 1 |
170 (170-170) |
6.5 (15-5) |
5 (5-5) |
NT |
15.4 (17.6-14.1) |
2 (2-2) |
11 (11-11) |
|
Aug 8 |
180 (180-180) |
5.5 (10-0) |
4.8 (5-4) |
NT |
14.9 (18-13.7) |
1.8 (2-1) |
10.9 (10.9-10.9) |
|
Aug 16 |
180 (180-180) |
41.1 (75-25) |
2.7 (3-2) |
30.0% |
14.1 (15.8-12.8) |
2.6 (4-1) |
11.3 (11.3-11.3) |
Premier Honeycrisp
Fruit tested represents fruit closest to maturity or first pick fruit in each block. Early fruit is nearing maturity in many locations for untreated fruit. First pick will likely begin by the end early next week, with a skim picking by the end of this week. Red color improved dramatically in some locations after the cool nights but is still less than desirable in other places. Background color beginning to yellow, but still fairly green in most of the samples tested, look for a change to light yellow. Seeds are beginning to turn brown in earliest fruit. Starch clearing is also evident in some individual fruit, although most sampled fruit were still between 1-2 SPI. Flavor and sugars also developing nicely, needing just a bit more time. A very small amount of bitter pit was observed in one location this week.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Ethylene (% >0.2ppm) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Aug 1 |
185 (210-160) |
5.75 (10-5) |
4.65 (5-4) |
NT |
20.225 (23.33-17.41) |
1 (1-1) |
10.9 (11.4-10.4) |
|
Aug 8 |
214 (240-180) |
5.2 (15-0) |
4.74 (5-3) |
NT |
18.32 (26.7-15) |
1.24 (6-1) |
10.4 (11.1-9.4) |
|
Aug 15 |
228.3 (270-180) |
38.3 (70-10) |
3.3 (5-2) |
40.0% |
16.7 (21.6-12.3) |
3.2 (7.5-1) |
12.8 (23.3-9.7) |
Paula Red
Red color very good in most places. Starch testing indicated some fruit was mature, some fruit still needs more time. Pressures starting to decrease in some places. Soluble solids acceptable, but still a little less than optimal. Picking by the end of the week or early next week.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Ethylene (% >0.2ppm) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Aug 1 |
170 (170-170) |
25 (30-0) |
4.7 (5-0) |
NT |
17.8 (22.21-15.19) |
1.6 (2-1) |
12.2 (12.2-12.2) |
|
Aug 8 |
210 (210-210) |
32 (45-20) |
4.7 (5-4) |
NT |
17.6 (21.9-15.4) |
2 (3-1 |
10.8 (10.8-10.8) |
|
Aug 15 |
170 (200-140) |
70.75 (90-50) |
3.7 (4.5-3) |
25.0% |
16.67 (21.6-13.13) |
3.5 (6-2) |
11.6 (12.1-11.1) |
Ginger Gold
Overall, samples taken this week indicated this variety needed a little more time for full maturity. Background still a little green, look for a change to light yellow to indicate maturity. Some fruit developing a minimal amount of pink coloring on sun-side of fruit. Flavor still developing, and sugars somewhat low. First picking at the end of the week or early next week.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Ethylene (% >0.2ppm) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Aug 1 |
185 (190-180) |
2.25 (5-0) |
4.6 (5-0) |
NT |
10.8 (25.1-19.1) |
1 (1-1) |
10.66 (10.8-10.5) |
|
Aug 8 |
203.3 (210-200) |
3.83 (50-0) |
4 (4-4) |
NT |
20.6 (25.1-18.2) |
1.1 (2-1) |
9.6 (10.6-8.2) |
|
Aug 15 |
260 (290-230) |
4 (5-0) |
3.2 (4-2) |
0% |
19.5 (22.7-17.2) |
1.2 (2-1) |
9.9 (10.7-8.9) |
Wildfire Gala
Samples this week showed maturity was progressing but needs a little more time. Red color is excellent, background color lightening, but still fairly green. Starch clearing evident in some fruit, but still very little in other individual fruit. Pressure still very high. Little sugar and flavor development. Harvest possible next week.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Ethylene (% >0.2ppm) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Aug 1 |
110 (110-110) |
32 (50-10) |
4.4 (5-4) |
NT |
20.03 (29.67-19.93) |
1 (1-1) |
9 (9-9) |
|
Aug 8 |
155 (160-150) |
33.25 (50-20) |
3.4 (4-3) |
NT |
21.45 (25.3-17.7) |
1.55 (4-1) |
9.85 (10.7-9) |
|
Aug 15 |
160 (160-160) |
78.0 (65.0-90.0) |
3.0 (3-3) |
0% |
22.4 (25.5-19.2) |
1.3 (2-1) |
10.1 (10.1-10.1) |
Gala
A few early samples of gala were collected this week, including Pacific and Brookfield strains. Fruit is still very immature.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Ethylene (% >0.2ppm) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Aug 15 |
125 (150-100) |
32.8 (70-2) |
3.4 (4-2) |
0% |
23.9 (30.3-18.8) |
1 (1-1) |
7.9 (9.8-0) |
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.
- Starch For Honeycrisp: will typically be rated using the standard Cornell SPI scale (1-8). However, a separate starch chart for Honeycrisp Apples developed by Washington State University (scale 1-6) also exists.
- 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 |
