Tree Fruit Maturity Report — September 12, 2025
Maturity Report
Pears
Pears have reached a stage of maturity where they should be harvested for storage. Flesh firmness was in the range of 14 to 17 lbs. for all three varieties in our collection. Pears left on the tree will continue to ripen but will not last in cold storage more than several days once they are fully ripe. Cold temperatures start the ripening process, and once it starts, it doesn’t stop, so pears become overripe and turn brown in the core after a few weeks in cold storage.
Apples
McIntosh harvest indices are listed in the table below. Starch and chlorophyll breakdown continued this week. Harvest for long-term storage should begin this week so that apples can be picked before they begin to drop. The first sign of fruit drop indicates when ethylene, the ripening hormone, has increased to a point where ripening will continue at a rapid pace and fruit will soften too much in storage.
Cortland is starting to ripen in some blocks but has not reached a stage that is best for long-term storage. This variety is prone to superficial scald and bitter pit, both of which are more severe when fruit are harvested too soon.
Macoun is not yet ready to pick for storage. Perhaps, next week.
Honeycrisp has reached a stage of maturity that is suitable for long-term storage in some blocks, but not in others. Check each Honeycrisp block individually because ripening is highly variable among different blocks. Fruit that are sufficiently ripe for storage will have a pale yellow-green color. Also, as peel chlorophyll breaks down, the red part of the peel will change from dull to bright red.
Honeycrisp apples that will be cold-stored longer than two weeks should be conditioned first. Hold them at temperatures in the range of 50 to 70 ºF for five to six days before placing in cold storage. Temperatures can be warmer than 70 ºF but shorten the conditioning period to three or four days. Gradually lowering the storage temperature is another option but hold apples at 50 ºF for at least four days. Please, ensure that conditioning rooms are well-ventilated to prevent oxygen from dropping below 16%, the minimum level that is needed to support human life.
- Reminder: Honeycrisp is sensitive to the elevated carbon dioxide that occurs in controlled atmosphere (CA) storage. Elevated CO2 causes large brown spots to develop in the flesh during CA storage. Other varieties are also sensitive when treated with SmartFresh or Hazel. Be sure to include enough lime in your CA rooms. Diphenylamine (No-Scald) will increase tolerance to carbon dioxide in CA storage, but it’s best to keep carbon dioxide below 1% in the first month of CA storage.
Other varieties: Summerset is a new one from the Midwest Apple Improvement Association that ripens with or just after McIntosh. At Highmoor Farm, they are ready for a first pick but will improve in quality with more time on the tree. Sweet 16 is an older variety from the Univ. of Minnesota breeding program. At Highmoor Farm, they need a few more weeks on the tree. Next week, we will begin testing late varieties such as Empire, Fuji and Evercrisp.
| Variety | Starch Index 9/2/25 | DA* 9/2/25 | Starch Index 9/9/25 | DA* 9/9/25 | Starch Index 9/12/25 | DA* 9/12/25 |
|---|---|---|---|---|---|---|
| Gala (Fulford) | 1.4 | 1.13 | 4.2 | 0.41 | ||
| Honeycrisp | 2.0 | 1.21 | 5.2 | 0.97 | 5.6 | 0.77 |
| McIntosh (standard) | 3.0 | 2.02 | 4.1 | 1.88 | 3.7 | 1.72 |
| McIntosh (spur type) | 2.9 | 1.89 | 3.8 | 1.79 | 4.3 | 1.80 |
| Cortland | 1.0 | 1.87 | 1.2 | 1.78 | 1.4 | 1.69 |
| Macoun | 2.2 | 2.04 | 2.4 | 1.93 | ||
| Summerset | 2.4 | 1.08 | ||||
| Sweet 16 | 2.4 | 1.69 |
* DA is a measure of chlorophyll breakdown in the peel which parallels ripening. Numbers decrease as fruits ripen. Gala and Honeycrisp readings between 0.8 and 0.3 indicate sufficient maturity for storage. McIntosh DA has not closely followed harvest maturity in years past and remains much higher than in other varieties. Cortland DA, in the past, has decreased below 1.5 during the harvest window.
The following is a rough guide to what the starch index numbers mean for apple ripening:
1 – 2: indicates lack of starch breakdown and generally unripe.
3: partially ripe, but prone to disorders in long-term storage.
4: typically ready to pick for long-term storage.
5 – 6: indicates good flavor and ready for general harvest or harvest for short-term storage.
7 – 8: indicates fully ripe, too ripe for long-term storage.
Renae Moran
University of Maine Cooperative Extension: Tree Fruits
PO Box 179
Monmouth, ME 04259
(207) 933-2100
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