Northwest Michigan apple maturity report – October 15, 2014

The northwest region continues to receive a lot of rainfall, which is slowing apple harvest in the north.

Cool weather and rain continues across northwest Michigan, and these conditions have slowed apple harvest. Growers have been working around the clock to take advantage of the intermittent dry spells between the rains. We had some light rain Wednesday through Friday last week, Oct. 8-10, prolonging the wet conditions. On Monday, Oct. 13, we received 1 inch of rain and 1.35 inches of rain on Tuesday, Oct. 14. Rainfall is continuing this morning, Oct. 15, and is predicted to continue throughout the day.

This week at the Northwest Michigan Horticulture Research Center (NWMHRC), many growers dropped off samples for testing because apple varieties have been slow to mature. In addition to slow ripening, the typical order of ripening for the many varieties has been variable. For example, most Galas are still not testing mature at this time, yet Jonagolds are testing mature this week. This situation is highly unusual and we do not have a good explanation for this scenario.

Honeycrisp have been coming off in the region and many apples are very large in size with good color. Color on all varieties is good this season. Cool but dry conditions are predicted for the remainder of the week, which will be helpful for growers to move ahead with harvest.

Summary of northwest Michigan apple maturity samples taken Oct. 14, 2014


Color % (range)

Firmness lbs. pressure (range)

Starch (range)

Brix (range)


86.0 (70-100)

17.4 (16.0-20.0)

5.7 (4-8)

14.7 (13.8-15.8)


86.5 (70-100)

18.9 (17.0-22.0)

2.4 (1-4)

12.5 (11.0-13.8)

Ida Red

86.2 (64-97)

17.5 (16.6-19.4)

3.5 (1.8-4.2)

12.3 (10.5-13.1)


77.0 (60-95)

15.8 (13.5-18.5)

5.8 (5-6)

12.0 (11.4-13.0)

Northern Spy

51.0 (30-80)

21.5 (18.0-23.5)

2.5 (2-4)

12.5 (11.0-14.2)

Golden Delicious

11.0 (0-30)

17.1 (16.0-19.0)

2.0 (3-9)

13.5 (11.8-15.0)

Red Delicious

99.4 (95-100)

18.9 (17.0-20.5)

2.0 (1-3)

12.5 (11.5-13.2)


98.0 (95-100)

20.3 (17.0-22.0)

4 (3-6)

11.8 (11.5-12.0)

Jonagold (one sample) are mature and many blocks have been harvested. Compared with other varieties, Jonagold brix levels are the highest we have seen this year and these apples are holding firmness.

Gala (one sample) are immature to mature. There continues to be high variability in maturation of Gala apples. Color, starch index levels and brix have not changed significantly in the last week.

Ida Red (seven samples) are mature with the exception of some blocks in northern Leelanau County. Brix levels have increased slightly and firmness is holding compared with last week’s samples.

Honeycrisp (one sample) are mature and many blocks have been harvested. These apples are ripe and could be approaching overripe in some blocks. Rain this week has likely contributed to lower brix levels.

Northern Spy, Golden Delicious, Red Delicious and Rome (one sample each) are immature.

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.

Dr. Rothwell’s work is funded in part by MSU’s AgBioResearch.

Did you find this article useful?

You Might Also Be Interested In