Northwest Michigan apple maturity report – October 8, 2014

Wet conditions have slowed apple harvest in northwest Michigan, and growers are waiting for clear days to pick the ripening crop.

The weather conditions are not cooperating with northwest Michigan apple growers as many apples are ripening quicker this week, but rain has kept them out of the orchards. At the Northwest Michigan Horticulture Research Center (NWMHRC), we received 0.82 inches of rain on Thursday, Oct. 2, 1.43 inches on Friday, 0.38 inches on Saturday, and just under 0.1 inches on Sunday. Growers were able to harvest apples on Sunday, Monday and Tuesday, and rain is predicted again for today, Wednesday, Oct. 8. However, the remainder of the week looks good for harvest.

Many growers moved into processing varieties in the middle of last week because fresh market varieties were not quite there, then the rains came, and growers are trying to get back into fresh market blocks with the increase in ripening in those varieties. Starch index readings on all of our tested fruit are much higher than our readings from last week, which indicates that many varieties are going to be ripe at a similar time. Growers are working hard to move through harvest. Color continues to be beautiful and fruit size is excellent. Overall fruit quality is very nice across northwest Michigan.

Summary of northwest Michigan apple maturity samples taken Oct. 7, 2014


Color % (range)

Firmness lbs. pressure (range)

Starch (range)

Brix (range)


68.0 (51-77)

16.6 (16.2-17.3)

5.8 (5.2-6.5)

14.5 (14.3-14.7)


80.0 (75-84)

18.3 (17.9-18.6)

2.5 (2.3-2.7)

12.2 (12.0-12.3)

Ida Red

77.3 (67-92)

17.9 (17.1-19.1)

2.6 (1.8-3.4)

11.6 (10.5-12.2)


77.0 (71-82)

15.6 (15.2-15.9)

5.7 (5.5-5.8)

12.9 (12.1-13.6)

Northern Spy

57.1 (43-71)

22.1 (21.0-23.1)

2.5 (1.3-3.2)

12.1 (11.4-12.6)

Golden Delicious

13.0 (5-25)

17.6 (16.0-19.0)

1.9 (1.0-3.0)

13.7 (13.0-14.5)


77.0 (60-90)

17.2 (15.0-19.0)

4.6 (3.0-6.0)

13.1 (12.5-13.4)


6.7 (0-20)

18.4 (17.0-22.0)

3.2 (2.0-4.0)

12.3 (11.0-14.0)

Jonagolds (three samples) are mature and have matured rapidly in the last week. Starch index levels and brix levels jumped up this week, indicating these apples are mature. Firmness is holding and comparable to last week’s measurements.

Gala (two samples) are immature to mature. Color, starch index levels and brix increased slightly compared with last week’s samples. Firmness is down slightly and many of these fruit are still not yet mature for fresh eating.

Ida Red (three samples) are immature.

Honeycrisp (two samples) are mature and many are ripe and approaching overripe in some blocks. These fruit are very large and have maintained firmness since last week. Brix levels are up slightly and many of these fruit have good color.

Northern Spy (three samples) are immature.

Golden Delicious (one sample) are immature.

Empire, Mutsu/Crispin (one sample) are mature. Apple maturity testing for one sample per each of these varieties indicated that these apples are approaching maturity or are mature.

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