Southeast Michigan apple maturity report – September 2, 2015

Harvest of summer apple varieties was wrapped up several weeks ago at most farms. Early Gala strains followed by McIntosh will begin in a few days.

General apple harvest comments

Harvest of the earliest maturing Gala strains will begin in the next few days, with McIntosh to follow quickly. Harvest of summer apple varieties was wrapped up a week ago at most farms. With the lack of a peach crop for many areas of the region this summer, tree fruit growers are anxious to get started with harvest of the first of the fall apple varieties. Most growers had plenty of moisture this season and thus fruit size is excellent. Fruit color is generally better than average, but with hot temperatures predicted for the next week, color may bleach out a bit. Two of the three varieties sampled this week, McIntosh and Honeycrisp, had fruit that had lower than normal fruit firmness or pressure tests. Harvest labor is short at most farms as we begin to ramp up apple harvest. This is the first East Michigan Apple Harvest Report for the season.

Apple maturity in east Michigan for apples harvested Aug. 31


% Fruits with Ethylene over 0.2 ppm (range)

Color % (range)

Firmness Lbs. (range)

Starch (range)

Brix %


80 (60-100)

73 (54-87)

18.1 (17.6-18.3)

1.6 (1.0-3.0)



 0 (0-0)

52 (37-64)

15.0 (14.1-16.0)

3.1 (2.0-3.7)



60 (20-100)

51 (40-76)

15.2 (14.3-15.7)

1.5 (1.2-2.1)


Individual variety results

Gala were sampled for the first week of the fall harvest season. Growers are looking to begin harvest of early maturing strains, like Fulford, and early maturing sites for long term and CA storage in the next few days. However, most other Gala strains do not eat well yet and growers are delaying harvest for fresh sales and midterm storage. With abundant moisture supplies for most growers this season, fruit size is excellent for growers that thinned well. I have not seen any stem end cracking on Gala yet this season. Gala are producing a good amount of internal ethylene, with 80% of fruit testing over the 0.2 parts per million (ppm) threshold. Color is generally fair to good in Gala this season, averaging 73%. The fruit remains firm averaging 18.1 lbs. The starch index averaged only 1.6, which is not quite at the 2.0 for long term and CA storage harvest.

McIntosh was sampled for the first week of the season and is still eating green. All blocks tested had no fruit with internal ethylene levels greater than 0.2 ppm. The color is generally poor to average in Mac’s at this time, averaging 52%, and the firmness was surprisingly low, averaging 15.0 lbs. The starch removal is fine at 3.1; recall that Mac’s need to be closer to 5 to be considered mature, higher than any other variety. The brix or sugar content is low at 11.7 percent. McIntosh needs at least a week to 10 days to be mature.

Honeycrisp were sampled for the first week of the season. Honeycrisp always have a wide range of fruit maturity, and this season it is typical; with fruit on the outside to the tree beginning to color and to eat a little better than fruit on the inside of the tree, which is green as grass. Internal ethylene fruit levels are typical for Honeycrisp, with fruit greater than 0.2 ppm approaching 60%. The color of fruit sampled from the outside of the tree is 51% and fruit are not as firm as typical, averaging 15.2 lbs. The starch removal averaged only 1.5, with a brix of 12.2%. In my opinion it is too early to jump the gun by beginning to even spot pick Honeycrisp.

Predicted apple harvest dates

Each year we publish a predicted harvest date for three varieties for many locations across the state. This year’s dates were published by Michigan State University Extension News on July 15 (see Predicted 2015 apple harvest dates). Table 2 lists the bloom and harvest dates for Deerfield and Romeo. You can adjust your predicted harvest dates based on your bloom dates. The harvest dates are based on a long-established formula using the bloom date and temperatures for 30 days post bloom. These dates are an estimate, and from the data I generated from this week’s samples, I believe that these predicted harvest days are going to be a few days later than the actual dates for a variety nearing maturity. Time will tell more of this story over the next few weeks, so keep a close eye on the weekly Apple Harvest Updates for possible revisions of these dates.

Predicted harvest dates for east Michigan

Full bloom date

 Predicted harvest dates




Red Delicious



Red Delicious















Looking for more? View Michigan State University Extension’s Apple Maturity Program and Reports resource page for regional reports throughout the state and additional resources.

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