Northwest Michigan apple maturity report – October 1, 2014

Apples are maturing slowly, growers are spot-picking Honeycrisp, and McIntosh harvest is underway.

After our week of beautiful, sunny, warm, fall days, the weather has turned cooler with clouds and rainfall. Cool weather and more rain are predicted for the remainder of the week. The region could use another dose of sunshine to move fruit along in maturity. Last week’s sunny conditions with the cool nights really improved color on all varieties, and fruit in well-pruned orchards has excellent color. Size in most varieties is also very good; some Honeycrisp apples that had a lighter crop on the trees are very large in size.

Growers are really starting to dive into harvest this week as many were waiting for better color and maturity. Processing apples are coming off now, and fruit will be used for many different end products. McIntosh is testing mature, but there is still a green background on many fruits and flesh of some apples still appears slightly green. Honeycrisp is eating well at this time and growers are doing a great job spot-picking this variety this year. Galas are maturing very slowly this season and starch index readings are still indicating immature fruit. 

Summary of northwest Michigan apple maturity samples taken Sept. 30, 2014


Color % (range)

Firmness lbs. pressure (range)

Starch (range)

Brix (range)


77.0 (60- 95)

16.2 (14.5-18.0)

3.2 (2-8)

13.3 (12.0-14.0)

Jonna Prince Red Jonagold

100 (100)

20.2 (16.5-23.0)

2.4 (2- 3)

14.7 (14.0-15.8)


77.0 (60-100)

19.9 (16.0-23.0)

1.5 (1-2)

11.8 (11.0-14.0)


69.0 (80-100)

15.3 (13.0-18.0)

5.9 (3-9)

13.2 (11.0-15.6)


71.5 (50-90)

14.6 (11.5-18.0)

4.8 (3-6)

12.4 (11.0-14.0)

Ida Red

75.0 (60-90)

17.9 (16.0-20.0)

1.8 (1-2)

12.3 (12.0-12.5)

Golden Delicious

10.7 (2-20)

17.3 (16.0-20.0)

1.9 (1-3)

12.9 (10.0-15.5)

Jonagold are immature (two samples). Firmness is down on Jonagold this week. Brix levels are consistent with last week and although starch levels are increasing, these apples are not yet ready for fresh market.

Jonna Prince Red Jonagold are immature (one sample). These apples have excellent color and brix levels are looking good. Firmness is high at 20.2 pounds and starch levels indicate that these apples are not quite ready.

Gala are immature (two samples). Color and firmness are consistent with last week’s samples. Starch levels and brix levels increased slightly.

McIntosh are immature to mature (two samples). We are continuing to see orchard to orchard and within orchard variability in percentage of color and starch levels on McIntosh. These apples are starting to soften and average brix levels remain low. Although testing parameters indicate maturity, many of these apples are still tasting green.

Honeycrisp are mature (two samples). Most Honeycrisp samples are ripe or ripening and firmness is down compared with last week. There has been good color on Honeycrisp and starch indexes indicate these apples are ripe. Average brix levels are consistent with last week.

Ida Red are immature (one sample).

Golden Delicious are immature (one sample).

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.

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