Grand Rapids apple maturity report - September 4, 2014

Gala and Macs are close with Honeycrisp coming soon.

General comments

In the Grand Rapids area, apple maturity seems to be running just about right in line with our predicted apple harvest dates. Paula Red and Gingergold harvest is nearly completed on the Ridge with good quality being reported. Fruit color, size and finish have been outstanding so far this season. In some cases, the earlier varieties look good enough to eat due to size and color, but are pretty starchy when you bite into them. Gala will be the next major variety for harvest for long-term CA storage in the Grand Rapids area with some starting in about 7 days. Macs and Honeycrisp are 7 to 14 days away from major harvest. For the Hart/Shelby area, growers can expect harvest dates for that area to be behind the Grand Rapids area using this guide - along the lakeshore approximately 6 days behind GR; areas inland about 4 days behind.

 Summary of Grand Rapids apple maturity samples measured September 3, 2014:


Avg. Ethylene

% Fruits with Ethylene
over 0.2 ppm

Color %

Firmness lbs
pressure (range)






80% (40 - 98%)

18.5 (16.5 - 21)


9.7 (9 - 10)




88% (70 - 99%)

15 (13.8 - 18)

3 (2 -4)

10.7 (10 - 12)




18% (5 - 50)

15.9 (14 - 19)

1.4 (1 - 3)

9.5 (9 - 10)


Color is good on most Gala strains this year, and size is excellent. Gala have moved towards maturity from early sampling last week and growers should watch their individual blocks very carefully. Our predicted harvest date for Gala was September 14th and that will be accurate for most sites. Some earlier strains of Gala should be at the stage for long-term CA storage very soon, with the majority of strains in that window early next week. Blondee maturity is similar to Buckeye Gala and both are expected to be at optimum long-term CA condition by the middle or late next week. We normally like to recommend a starch index of 3 for long-term storage of Gala, but if color and size are where you need them, you could pick for long-term CA storage at a starch of 2.


They are not quite there yet in the general Grand Rapids area and they eat very starchy. Ethylene is low with no fruits being over 0.2 ppm. Pressure readings are indicating good firmness at an average of 15 pounds of pressure. Color is excellent of course on Ruby Mac and very good in other mac strains and improving every day. Brix reading is rather poor at 10.7, but is expected to improve in the next 10 days. Harvest for long-term storage of Macs can begin at any time color is right, with the majority of harvest coming in 10 to 14 days. Our predicted harvest date for Macs is September 19. Be watchful in blocks with a heavy fruits set as drop could occur from fruits pushing themselves off. Macs appear to be 1 to 2 days ahead of Honeycrisp.


Moving toward maturity, but still immature overall - there are a few fruits that are near ready, but the majority of Honeycrisp are not physiologically ready for harvest in the Grand Rapids area - being economically ready is a different story, with a bitter ending if done too soon – you can kill return sales by picking subpar HC too soon. I haven’t seen any HC blocks around the Ridge that will warrant a first pick next week. Firmness readings are good to excellent at 15.9 pounds pressure on average, indicating immaturity. Starch readings are very low and also indicate immaturity. Brix level is very low at 9.5. Our predicted harvest date of September 22 seems accurate for the majority of Honeycrisp around the Ridge. Initial first picking of Honeycrisp for fresh sales is recommended 10 to 14 days from now in the Grand Rapids area.

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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