Northwest Michigan apple maturity report – September 30, 2015

Honeycrisp harvest is underway, and some blocks are coloring up nicely while other growers are waiting on this variety to develop more color.

The warm weather has hastened the ripening of all apple varieties. These temperatures have caused some concern as the fruit is testing mature, but the color is just not “there” in some blocks. However, despite the warm temperatures, color on most varieties is looking better and better; we anticipate color to improve even more with the cool weather and sunny days that are predicted for the remainder of the week in northwest Michigan.

Firmness in Galas is holding well, and color across the strains looks excellent. The starch index average for Galas is 3.0. McIntosh from this week’s samples are still testing firm, and color is good. Macs are still eating a little on the green side. Honeycrisp firmness is lower this week, but this variety is eating well and brix levels are excellent. According to growers across the region, color is variable in this variety, and this cool weather is a blessing for those blocks that are testing mature but still need more color. Jonagold brix is high (averaging 14.5 in two samples), but more color is needed and the fruit are still not testing mature. Ida Reds still have time to go before they are mature, but the color has improved over the last week.

Summary of northwest Michigan apple maturity samples taken Sept. 29, 2015


Color % (range)

Firmness lbs. pressure (range)

Starch (range)

Brix (range)


89.3 (80.5 – 94.0)

19.5 (19.1 – 19.7)

3.0 (2.8 – 3.1)

11.5 (11.0 – 11.9)


96.0 (92.5 – 99.0)

17.2 (16.6 – 17.7)

3.0 (1.2 – 4.8)

12.0 (11.5 – 12.4)


78.3 (67.0 – 89.5)

14.7 (14.5 – 14.8)

4.7 (3.6 – 5.7)

11.7 (10.5 – 12.9)


63.8 (53.0 – 74.5)

17.4 (17.0 – 17.7)

3.0 (2.7 – 3.2)

14.5 (14.3 – 14.6)

Gala (three samples). The target starch index for Gala long-term storage is 3. Firmness of this variety remains high, color has improved, and brix levels have also risen to 11.5.

McIntosh (two samples). McIntosh ripeness is variable among blocks with some Mac blocks indicating that the apples are mature with a starch index of 4-5 and other blocks with a lower starch index (1.5-2); apple blocks with these lower starch index readings are not yet ready for picking.

Honeycrisp mature (three samples). Many Honeycrisp blocks are mature and harvest of this variety is ongoing. Firmness has decreased from an average of 14.7 to 16.3 pounds this week.

Jonagold (two samples). This variety is approaching maturity and overall quality looks good. Brix levels remain high; firmness has decreased 1 pound since last week.

Ida Red (one sample). Ida Reds are not yet mature with an average starch index of 1.7. An average brix level of 11.9 indicates this variety is getting closer to maturity.

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

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