Northwest Michigan apple maturity report – September 11, 2013

Gingergold harvest is underway in northwest Michigan, and cooler temperatures over the weekend will help color later varieties.

Weather conditions remain dry across the region. We received just under 0.25 inches of rainfall on Aug. 30 - Sept. 1, 2013, and a very small amount – less than 0.05 inches – on Sept. 7. Apples without irrigation would benefit from rain to help them size. Color has improved in the past week on many varieties, but cooler nights are needed to really put some color on the fruit. The current conditions across the northwest are hot and humid, and nighttime temperatures have remained in the mid-50s to mid-60s. However, temperatures are predicted to cool down over the weekend.

Honeycrisp vary in color, but most fruit are still on the green side. Some growers have placed white reflective material in between rows to improve color, particularly in orchards adjacent to wood lines. Insect and disease issues on fruit are minimal at this time, and overall growers are pleased with the crop load and quality of the fruit.

Summary of northwest Michigan apple maturity samples taken on Sept. 10.


Color % (range)

Firmness lbs. pressure (range)

Starch (range)

Brix (range)


70 (40 - 95)

20.6 (17 – 23.5)

1.4 (1 - 4)

10.8 (9.4 – 12.6)


66 (20 - 95)

18.1 (14 - 23)

1.6 (1 - 3)

11.7 (11 - 13)


44 (10 - 90)

18.0 (16 - 21)

1.7 (1 - 6)

11.9 (10 – 15.6)

Gingergold. Mature (no samples tested). Harvest is continuing. Background color should just be starting to turn yellowish at the time of harvest. Fruit that ripens to the point of full yellow will not hold up well in storage.

Gala. Immature (two samples). Firmness is at 20.6 pounds, down from 21.8 pounds. Starch index is at 1.4, up from 1.1, and brix levels are up slightly to 10.8. Color has improved to 70 percent.

McIntosh. Immature (two samples). Firmness is at 18.1 pounds, down from 19.2 pounds. Starch index is at 1.6, up from 1.4, and brix levels have increased to 11.7. Color has improved to 66 percent.

Honeycrisp. Immature (three samples). Firmness is at 18.0 pounds, down from 19.3 pounds. Starch index is at 1.7, up from 1.4, and brix levels have increased to 11.9. Color has improved slightly to 44 percent. This variety needs multiple pickings over several weeks for premium quality fruit. Watch for first two to three apples per tree to color for the first picking.

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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