MSU Extension Apples

This is the fifth apple maturity report for the 2021 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.

• Considerations for the 2021 harvest season can be found in this article.
• 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

For each variety evaluated, we provide data from our evaluations in a table. In each, a row is provided for each sample tested. This allows you to see how the varieties may be progressing in different regions or specific locations. An average is included 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. Recommended values are included for each variety at the bottom of the table. These suggested values for firmness and starch index were also published in a standalone table format. Firmness ranges encompass long and short-term storage recommendations.

Updates for this week

The weather is still warm and seems like summer, but the forecast is predicted to cool down and feel a lot more like fall for the remainder of the week. We had great warm weather over the weekend, which was good for soccer games but still warm for coloring up apples. The forecasted cool weather should help putting the red cheeks on our fruit. Fruit is looking redder than in past weeks, but still a bit shy of where we hoped to be for this season.

In addition to warm weather, we received rain on Sunday night and into Monday (Sept. 20-21), and again the rain came down hard at some times and caused wash out on roads and in orchards. As of Tuesday evening, Sept. 21, the Enviroweather station at the Northwest Michigan Horticulture Research Center recorded 0.41 inch of rain. We also had some rain the past Tuesday, Sept. 14, and the Northwest Michigan Horticulture Research Center recorded 0.11 inch of rain.

The unusual thing about rainfall this season has been the intensity of the rain, even if the total amounts are not much. The rain seems to come in very intense falls that last for a short time but cause a lot of wash out and wash off for cover sprays. The rains are often followed with sun and nice weather, but these predictions sense change coming in the winds. We are expecting cooler weather and more cloudy days in the coming weeks, but we are still hoping for sunshine to color up the fruit.

We tested four samples of McIntosh this week. The fruit is eating better compared to past weeks, but the brix levels are still on the lower side.

We tested four samples of Honeycrisp this week, and fruit has moved along in maturity compared to last week. Color is still not excellent in our samples, but we are hoping that the cool weather will help color up this fruit. The fruit is juicy and crispy, but again we are hoping that the brix levels will increase in the coming weeks. Color on the Honeycrisp at the station is improving, but the flavor of our fruit is not excellent. Many of our samples have much reduced firmness levels this week compared to weeks past.

We tested Gala for the fourth time this week. Fruit from the different samples is again showing considerable differences in maturity, similar to last week. The brix levels in our Gala samples are lower than we anticipate for this time of year. The color on this variety is improving, but the sugars are still lower than we would hope for this sweet variety. Growers are picking Galas throughout the region at this time.

Predicted harvest dates, according to the Maturity Model in Enviroweather, are about 10 days earlier than normal for early varieties (Gala, Honeycrisp, McIntosh). At this time, we believe these will be fairly accurate. However, we were predicted to harvest McIntosh on Sept.14, and this variety is now showing maturity at this time.

McIntosh

We tested four samples of McIntosh again this week. Firmness is less than last week, but the ranges are similar to the past week. Color is variable, and we had quite the range of color, and some apples are remarkably green for this variety. Starch removal readings increased from 3.0 to 4.4 this week, but there is still a range in starch removal measurements. Brix in McIntosh has remained consistent over the past three weeks but has increased a little bit this week.

Honeycrisp

Honeycrisp spot picking is underway across the region. Color is still not where we would like it to be for this variety. Firmness also varies between the samples, but the average firmness levels are almost exactly where we were last week. Starch removal numbers have increased, and we had an average of 4.7 this week with a range of 3 to 6. Again this week, brix numbers did increase, but we still have low levels of brix in some of our samples. We had samples that were up in the 14 range but also had samples in the about 10 range. We have a block at the Northwest Michigan Horticulture Research Center where we have seen considerable bitter pit compared to last week. We also have reports of bitter pit in blocks where the crop load was low.

Gala

We tested four samples of Gala again this week, and color on this variety has improved over last week; color increased from 82% to 86%, but a range is still notable from 60-95% red color. Firmness in this variety is still holding exceptionally well again this week, and we see only a small drop in firmness from past weeks. Starch removal increased this week, and we had an average starch removal of 4.1, but the range is quite noticeable: 2 to 8. The apples we tested were again quite low in brix content, and the lack of sugars in the fruit is apparent when you eat them. We hope that the coming weeks will help increase brix levels in all varieties. We did increase our average brix from 10.3 to 11.1. We still are seeing a range in brix from 9.8-12.

Apple maturity sampling parameters

• Color % = the visual percentage of red color from 0 to 100; 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.