Michigan apple maturity reports – October 19, 2011

Each week, MSU Extension educators test apples for maturity in their region and report the status.

This week’s regional reports:

Southeast Michigan – Bob Tritten and Debbie Clark, Michigan State University Extension

Southeast Michigan
Southeast Michigan

General harvest comments

The word from many apple growers concerning apple harvest this week is that they can “see the light at the end” of the apple harvest tunnel. Many growers report that they will be wrapping up with most of their apple harvest by this weekend or early next week. The exception to this is growers who are holding on to some apples for pick-your-own sales for the next two weekends. There are a few varieties like Granny Smith and Winesap that are not mature yet, but the rest are moving toward maturity quickly.

Most growers are harvesting several varieties at the same time and are pushing hard toward finishing up. Fuji were harvested late last week. Growers are currently harvesting Red Delicious, Northern Spy and Idared. Law Rome’s and some blocks of Braeburn are now ready for harvest.

Fresh market and pick-your-own sales have been very strong at all farms this fall. With less than ideal weather last weekend, demand at farmer’s markets for pick-your-own sales was off a bit from previous mid-October weekends. With favorable weather predicted for this weekend, it should be another high demand weekend.

This week I sampled nine varieties, however the number of samples was limited because many of the blocks that I have been harvesting over the last few weeks have now been harvested. Remember that the order of maturity of apple varieties continues to unfold differently this year than it has in most years. This is certainly true right until the end of harvest this year. For example, Idareds are now mature before Red Delicious.

It appears at this writing that this will be the final east Michigan apple harvest report for the 2011 growing season. I trust that you have found these reports to be helpful and that you have utilized them throughout the harvest season to make sense of this wild and wacky growing season and apple harvest.

Apple maturity in east Michigan for apples harvested on October 17

Variety % Fruits with Ethylene over 0.2 ppm (Range) Color (Range) Firmness Lbs (Range) Starch (Range) Brix %
Empire 50% (50-50%) 78% (50-95%) 14.5 lbs (11.4-17.4) 7.0 (6.0-8.0) 12.4%
Red Delicious 85% (70-100%) 97% (97-97%) 17.0 lbs (15.3-18.6) 4.3 (3.8-4.8) 12.7%
Northern Spy 100% (100-100%) 38% (10-60%) 19.4 lbs (15.6-21.6) 5.6 (4.0-7.0) 12.4%
Idared 98% (90-100%) 84% (80-87%) 14.7 lbs (12.3-16.4) 5.4 (4.9-6.0) 12.4%
Law Rome 80% (80-80%) 95% (85-100%) 19.3 lbs (16.6-19.9) 5.6 (5.0-7.0) 12.4%
Winesap 100% (100-100%) 86% (78-93%) 19.1 lbs (18.5-19.7) 2.8 (2.5-3.1) 12.4%
Braeburn 75% (70-80%) 79% (69-88%) 20.4 lbs (20.2-20.6) 4.4 (4.4-4.4) 11.3%
Granny Smith 40% (40-40%) 28% (5-70%) 17.8 lbs (15.2-20.4) 2.6 (1.0-4.0) 11.0%
Enterprise 80% (80-80%) 86% (75-95%) 20.0 lbs (17.5-21.5) 3.5 (3.0-4.0) 12.6%

Individual variety results

Empire were not sampled last week, but I found a few blocks that had been left unharvested, primarily for pick-your-own. So as a curiosity to see how far they have come along, I sampled those blocks. With the fruit that remains, 50 percent of the fruit are showing internal ethylene levels greater than 0.2 parts per million (ppm). The fruit remain well-colored at 78 percent and the background is testing mature at 1.3. The fruit that remain on the tree (these trees have been spot picked) remain firm at 14.5 lbs. However, the starch removal index is averaging 7.0, indicating that, indeed, they are over-mature for most markets. The starch index two weeks ago was 5.0. The brix or sugar level in the fruit remain high at 12.4 percent.

Red Delicious were sampled for the fifth week of the season, and as indicated last week, Red Delicious have been very slow to mature at many farms, particularly the Red Chief strain this year. I was only able to sample two blocks this week, as most Red Delicious have already been harvested. With the blocks that remain, 85 percent of the fruit are showing internal ethylene levels greater than 0.2 ppm. Color remains very good at 97 percent. The fruit remain firm at 17.0 lbs, virtually unchanged from last week. The starch index is also remaining about the same at 4.3, with a brix of 12.7 percent. As I indicated in last week’s report, Red Delicious were picking very easy and are starting to see some increased amounts of fruit drop, particularly with windy conditions that we experienced over the weekend. The blocks of Red Delicious that remain unharvested are still suitable for medium and long-term storage harvest, as well as fresh sales.

Northern Spy were sampled for the fourth week of the harvest season, and with a limited number of samples being taken this week because most blocks have been harvested. The fruit have a great deal of internal ethylene, with 100 percent of the fruit tested showing levels greater than 0.2 ppm. Color remains about the same and firmness has also remained close to the same, now at 19.4 lbs. The starch index, however, has moved from 4.3 last week to 5.6 this week. The fruit brix is 12.4 percent. These fruit remain firm and are ready for harvest for both long-term storage and fresh sales.

Idared were sampled for the fourth week of the harvest season with a good number of blocks being sampled this week. Idared are showing high levels of internal ethylene development, now at 98 percent. Fruit color is very good at 84 percent and background color has dropped from 2.5 last week to 1.9 this week. Fruit remain firm at 14.7 lbs. The starch removal index has jumped from 3.8 last week to 5.4 this week and the brix is 12.4 percent. Idareds are ready for harvest and a few blocks are over-mature for long-term storage.

Law Rome were sampled for the third week of the season and only one sample being available for testing this week as most have been harvested. Eighty percent of the fruit are showing internal ethylene levels greater than 0.2 ppm and the fruit remain well-colored at 95 percent. The background color has dropped from 2.5 last week to 1.0 this week. The fruit remain very firm at 19.3 lbs. However, the starch index has moved from 5.1 last week to 5.6 this week, with a brix of 12.4 percent. Law Romes are also ready for harvest.

Winesap were sampled for the third week of the season. The maturity of Winesap is very slow this year. All (100 percent) of the fruit are showing internal ethylene levels greater than 0.2 ppm and the color has improved to 86 percent. The background color has dropped from 3.0 last week to 1.3 this week. The fruit remain firm at 19.1 lbs with a starch removal index of 2.8, and a brix of 12.4 percent. Winesap are not ready for harvest. I would expect that in about a week they will be mature.

Braeburn were sampled for the third week of the season with a consistent number of samples being taken this week as no blocks of Braeburn have been harvested. The internal ethylene levels have remained constant at 75 percent of fruit showing internal ethylene levels greater than 0.2 ppm. The fruit color has improved from 61 percent last week to 79 percent this week. The background color has also dropped from 3.4 last week to 1.5 this week. The fruit remain very firm at 20.4 lbs and the starch removal index has jumped dramatically from 2.8 last week to 4.4 this week, with a brix of 11.3 percent. Most blocks of Braeburns are nearing maturity and are ready for long-term and controlled atmosphere storage harvest. For fresh sales, I would give them another three or four days before harvest to let them eat a little bit better.

Granny Smith were sampled for the second week of the fall harvest. The internal ethylene levels greater than 0.2 ppm have moved from 10 percent last week to 40 percent this week. The fruit are starting to get a nice blush, however the background color is still very green. The fruit remain firm at 17.8 lbs, with a starch index of 2.6 and a brix of 11.0 percent. Granny Smith are still not mature and need most likely another 10 to 14 days before the apples will begin to mature.

Enterprise were sampled for the second week of the season with only one block being tested. Enterprise are not a widely planted variety across the region, but are beginning to gain in popularity. The internal ethylene levels greater than 0.2 ppm have jumped from 20 percent last week to 80 percent this week. The fruit remain well-colored at 86 percent and the background has dropped from 2.3 last week to 1.6 this week. The fruit remain very firm at 20.0 lbs. The starch removal index has moved from 2.3 last week to 3.5 this week, with a brix of 12.6 percent. One of the challenges of growing Enterprise is they turn greasy very quickly in the fall, and because of this I would think that Enterprise are ready for medium and long-term storage, and will be ready late this week for fresh market sales. While they are not necessarily philologically mature, because of this greasiness I would go ahead and harvest them.

Predicted harvest dates

Full bloom date Original Predicted Harvest Dates Revised Predicted Harvest Dates
Station McIntosh Jons Reds McIntosh Jons Reds McIntosh Jons Reds
Deerfield 5/13 5/15 5/17 9/15 9/29 10/5 9/20 10/4 10/10
Romeo 5/19 5/21 5/21 9/17 10/2 10/8 9/22 10/7 10/13

If you have any questions regarding this apple maturity report or apple harvest in southeast Michigan, don’t hesitate to email me, call my office (810-244-8555) or cell (810-516-3800).

This report and project is made possible by the support of our sponsors, which include Valent Biosciences,Michigan Apple Committee, Michigan State Horticultural Society,MSU’s AgBioResearch and Michigan State University Extension. Southeast Michigan apple growers that are providing apples on a weekly basis include Spicer Orchards in Hartland, Erwin Orchards in South Lyon, Westview Orchards in Romeo and Hy’s Cider Mill in Romeo. Many thanks to the support of these growers.

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Grand Rapids Area
Grand Rapids Area

Grand Rapids Area – Phil Schwallier, Amy Irish-Brown, Denise Ruwersma, Michigan State University Extension

General comments

Harvest on the Ridge is moving along very quickly with some varieties maturing ahead of predicted harvest dates. Some rather stiff winds moved through late last week and some drop was seen. Cold, wet weather moved in today, October 19, and the wind has started to increase again this afternoon.

We collected maturity samples on several varieties that are normally long done with harvest by now. These were treated with Retain and included Gala, Honeycrisp, Empire, Jonagold, Cortland, Spy, Golden Delicious and Early Fuji. All of these fruits are now in an over-mature state and no longer suitable for even short-term CA storage.

Summary of Grand Rapids apple maturity samples tested October 18, 2011

Variety Predicted Harvest Date Avg. Ethylene (ppm) % Fruits with Ethylene over 0.2 ppm % Red Color (range) Firmness lbs pressure (range) Starch (range) Brix (range)
Idared 12-Oct 5.82 100% 79% (60-95) 17.6 (14.6-20) 4.8 (3-7) 13.6 (13-14)
Rome 17-Oct 4.26 85% 97% (90-100) 20.3 (16.5-22.5) 6.7 (6-8) 11.7 (11-13)
Cameo 17-Oct 30.5 100% 92% (80-100) 18.4 (15.5-21.4) 6.4 (5-7) 12.7 (12-14)
Fuji 27-Oct 0.817 100% 66% (55-80) 16.5 (14.2-18.9) 6.4 (5-7) 12.8 (12-14)
Braeburn 28-Oct 3.65 100% 54% (30-75) 18.4 (16.5-19.9) 5 (4-6) 10.2 (9-12)
Granny Smith 1-Nov 0.383 100% 8% (0-15) 17.9 (16.2-19.9) 5 10.9 (10.5-11)

Red Delicious

Most Red Delicious have been harvested. There are a few Retain-treated fruit still around and they are quickly moving to only being suitable for short-term CA storage. There has been some water core found in late hanging fruit.


Growers put a big dent in Idared in the last week. Our samples from this week indicate that Idared are still suitable for mid-term CA storage, but they will quickly move beyond that unless they’ve been treated with Retain. Internal ethylene is indicating mature fruits with very high levels. Starch clearing is still on the low side at 4.8 compared to 4 last week, indicating they are still suitable for mid- to long-term CA storage. Brix have improved from 12.2 last week to 13.6 this week. Don’t wait too long to finish up with Idared that have not been treated with Retain.


Last week’s samples indicated that Cameo was in the range for long-term CA storage, however, having very little maturity data on this variety, the predicted harvest date is still somewhat unclear. Having heard from a few growers with experience with Cameo, they say it’s later than Red Delicious and perhaps more in line with Rome harvest. The samples this week show a slight improvement from last week and still indicate good levels for long-term CA storage. In other words, they haven’t moved forward in maturity very quickly from last week to this week. We continue to learn more each year about this newer variety and have adjusted the predicted harvest date from October 8 to October 17, in line with Rome. We welcome all feedback.


Romes have moved rather quickly into the long-term storage window and many have been harvested on the Ridge in the last two days. Internal ethylene jumped from only 10 percent of fruits over 0.2 ppm last week to 85 percent over 0.2 ppm this week. Firmness is still excellent at an average of 20.3 pounds this week compared to 21.1 last week. Starch conversion is 6.7 on average and very similar to last week. Brix has improved a bit from 11.3 last week to 11.7 this week. This will be a big week for getting Romes in bins.

Fuji (late season)

This is the fourth week of sampling for late season Fuji. Overall, they are still on the immature side, but the numbers indicate they will most likely be ready for long-term CA storage by the weekend and well ahead of the October 27 predicted harvest date. Growers should start looking at Fuji closely in the next few days and monitor their development – there are different cultivars of late Fuji and they are all just slightly different in maturity.


The predicted harvest date for Braeburn is usually slightly ahead of Granny Smith for the Grand Rapids area. We are predicting October 28 for 2011. We sampled them for the first time this week. Data indicates Braeburn is showing signs of maturity. Internal ethylene is a bit surprising at an average of 3.65 ppm with 100 percent of fruits being over the 0.2 ppm climacteric. Red color is OK at 54 percent and should improve in the next 7 to 10 days. Firmness is excellent at 18.4 pounds on average. Starch clearing is 5 which indicates an early maturity stage. Brix are poor at 10.2 and should also improve in the next 7 to 10 days.

Granny Smith

Granny Smith were sampled for the third week in a row and are still on the immature side, but have made good forward movement in maturity this week compared to last. Internal ethylene has increased from 0 percent fruits over 0.2 ppm last week to 100 percent being over 0.2 ppm this week. Overall, internal ethylene is still quite low, averaging only 0.383 ppm this week – most fruits are right at the 0.2 ppm climacteric indicator for mature fruit. They are still very hard at 18.4 pounds on average this week compared to 20.3 pounds last week. The starch clearing is similar to the last three weeks at 5. Brix readings are good, but slightly down from last week at 10.9 this week. The normal harvest date for Granny Smith in the Grand Rapids area is around November 10. We continue to predict they will be earlier this year, perhaps around November 1.

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