2025 Pennsylvania Tree Fruit Maturity Report - September 23
Introduction
Welcome to Pennsylvania State Extension's weekly tree fruit maturity report! Maturity metrics for key varieties will be tracked across the state throughout the 2025 season. Informed harvest timing is critical for fruit quality, particularly for apples in mid- to long-term storage. Balancing sugar accumulation, color development, starch clearing, and pressure loss is difficult to manage. These reports serve to provide insight and help inform management decisions.
These reports are collated on a "landing page" (termed a "campaign" by Penn State) that can be bookmarked for future reference. Every report issued will appear on the campaign page, often prior to being sent out via email. Missed a report last week or need to review a recommendation? Reports for the entire season will be collected there for quick access.
Informed harvest timing is critical for fruit quality, particularly for apples in mid- to long-term storage. Balancing sugar accumulation, color development, starch clearing, and pressure loss is difficult to manage. These reports serve to provide insight and help inform management decisions.
Weather and Color Development
The small rain events are continuing this week in Adams County with a total predicted precipitation of 0.64 inches over several days. The temperatures continue to be good for color development, but the cloud cover can reduce potential reddening this week. If the predicted precipitation comes through, it can help with fruit sizing but can also increase the risk of cracking in overmature fruit.
The monthly and seasonal temperature outlooks from the National Weather Service predict that Pennsylvania is moving into an above average temperature period this harvest season. Temperature impacts color development in fruit, though reddening can be encouraged with appropriate management techniques. High temperatures at harvest also affect fruit quality in storage. Consider these handling guidelines from Michigan State University when managing harvest in hot weather.
Storage Options
Storing fruit properly is critical for maintaining fruit quality and integrity. Recommendations specific to different cultivars change and get more specific as researchers continue to study the impact of different storage conditions on fruit quality. Below are recent recommendations on apple storage:
- Presentation available from 2024 Controlled Atmospheric Storage Clinic
- Link above includes research on Ambrosia, EverCrisp, Gala, and Honeycrisp storage practices and physiological disorders.
- Fruit Disorders- Practices to Manage Storage Disorders in Honeycrisp
Adams County
Maturity samples were collected from two orchards in Biglerville (Adams County). Please adjust harvest decisions based on the specific conditions at your site.
| Date | Mass (g) |
Diameter (in) |
Red Color (%) |
Background (1-5) |
Firmness Average (lb) |
Starch Index (1-8) |
Soluble Solids (°Bx) |
|---|---|---|---|---|---|---|---|
| Crown™ Empire | |||||||
| 9/21 | 160 | 2.8 | 86.5 | 2.1 | 20.7 | 5.5 | 12.5 |
| 9/15 | 170 | 2.9 | 88.0 | 3.0 | 20.6 | 4.7 | 12.5 |
| 9/8 | 158 | 2.9 | 92.5 | 1.7 | 20.5 | 4.3 | 12.2 |
| Fuji (Aztec®) | |||||||
| 9/21 | 197 | 3.0 | 48.0 | 2.2 | 19.8 | 3.3 | 14.2 |
| Nittany * | |||||||
| 9/21 | 230 | 3.2 | 53.5 | 2.3 | 22.7 | 2.9 | 13.0 |
| 9/15 | 262 | 3.4 | 25.0 | 1.7 | 20.0 | 2.4 | 11.1 |
| Red Delicious (Super Chief® / Sandidge cv.) * | |||||||
| 9/21 | 212 | 3.1 | 87.0 | 1.6 | 18.5 | 4.2 | 12.7 |
| 9/15 | 256 | 3.3 | 98.3 | 1.0 | 17.4 | 4.1 | 11.1 |
| 9/8 | 264 | 3.3 | 95.1 | 1.1 | 19.2 | 3.4 | 11.7 |
| 9/2 | 206 | 3.1 | 91.3 | 1.3 | 19.3 | 3.1 | 11.2 |
| 8/25 | 190 | 3.0 | 83.0 | 1.8 | 19.6 | 2.6 | 9.0 |
*Fruit was collected from two orchards.
Crown™ Empire
Crown™ Empire is moving into its maturity window. The fruit firmness is still high at 20.6 lb for the third week in a row, but the starch clearing (5.5) is moving along quickly. The sizing, color, and sugar content are strong currently. This variety should be monitored closely this week and harvested shortly.
Fuji (Aztec®)
Aztec® Fuji is moving along in Adams County. These apples have excellent sugar accumulation (14.2 °Bx) and the starch clearing is underway (3.3). The pressure is still fairly high at 19.8 lb, which will give time for the blush color (48%) to develop in the next couple of weeks. The Aztecs might be ready for harvest in two weeks based on how quickly they clear starch.
Nittany
Between the lower starch index value at 2.9 and the higher fruit firmness at 22.7 lb this week, Nittany is not currently ready for harvest. However, it should be watched in the next two weeks. The sugar content has grown in the past week to 13 °Bx. This great sugar content should only increase as the Nittany apples continue to mature.
Red Delicious (Super Chief® / Sandidge cv.)
Red Delicious is mature in Adams County. The fruit firmness and starch index values are progressing substantially for the first time in three weeks. The red coloration is excellent. The sugar content has also caught up with the rest of the fruit maturity this week and has reached a strong 12.7 °Bx.
Berks County
Maturity samples were collected from two orchards in Boyertown; please adjust harvest decisions based on specific local site conditions.
| Date | Mass (g) |
Diameter (in) |
Red Color (%) |
Background (1-5) |
Firmness Average (lb) |
Starch Index (1-8) |
Soluble Solids (°Bx) |
|---|---|---|---|---|---|---|---|
| EverCrisp® | |||||||
| 9/22 | 214 | 2.6 | 50 | 2 | 20.4 | 5.8 | 15.1 |
| Fuji (Aztec®) | |||||||
| 9/22 | 163 | 2.3 | 55.5 | 2.1 | 18.1 | 2.8 | 12.9 |
| Jonagold | |||||||
| 9/22 | 213 | 2.5 | 69.5 | 1.3 | 16.3 | 6.6 | 14.2 |
EverCrisp®
EverCrisp is entering its maturity window in Berks County. While the firmness for EverCrisp is still quite high (20.4 lb), the starch index value (5.8) and sugar accumulation (15.1 °Bx) are quite progressed. Hot days and cool nights lead to the faster starch clearing in varieties like Evercrisp and it should be taken into account when considering long-term storage. EverCrisp apples are known to be very dense which tracks with the high pressure and otherwise very mature fruit. Keep in mind that trucks loaded with EverCrisp should be loaded 7-10% lighter than other apple varieties to maintain weight restrictions in transit.
Fuji (Aztec®)
Aztec Fuji are not yet mature in Berks County. Both the starch index value (2.8) and pressure (18.1 lb) need development to reach maturity. The sugar accumulation is currently strong (12.9 °Bx), but it will improve as this variety reaches maturity in the next two weeks.
Jonagold
Jonagold is currently mature across all metrics. This variety should be targeted for harvest this week. The pressure is currently 16.3 and should do well in storage. However, track pressure closely if there are any delays in harvesting Jonagold in the area.
Centre County
Maturity samples were collected from one orchard in Centre County; please adjust harvest decisions based on specific local site conditions.
| Date | Mass (g) |
Diameter (in) |
Red Color (%) |
Background (1-5) |
Firmness Average (lb) |
Starch Index (1-8) |
Soluble Solids (°Bx) |
|---|---|---|---|---|---|---|---|
| Ambrosia (DT2.cv) | |||||||
| 9/22 | 173 | 2.9 | 74.5 | 1.0 | 18.0 | 5.3 | 14.0 |
| 9/15 | 171 | 2.8 | 65.0 | 1.9 | 21.5 | 2.1 | 13.2 |
| 9/8 | 181 | 2.9 | 50.0 | 1.8 | 20.6 | 1.2 | 11.9 |
| Crimson Crisp® | |||||||
| 9/22 | 182 | 2.9 | 88.0 | 1.0 | 21.0 | 6.7 | 14.6 |
| 9/15 | 163 | 2.8 | 94.0 | 1.3 | 22.2 | 4.7 | 14.1 |
| Fuji (Aztec®) | |||||||
| 9/22 | 192 | 2.9 | 55.5 | 2.1 | 19.2 | 3.1 | 13.4 |
| 9/15 | 166 | 2.8 | 57.5 | 3.3 | 21.4 | 1.8 | 12.6 |
| 9/8 | 171 | 2.8 | 40.5 | 2.9 | 20.7 | 1.9 | 11.8 |
Ambrosia (DT2 cv.)
Ambrosia is mature in Centre County this week with progress across the maturity ratings. The starch index value (5.3) progressed from last week (2.1). The pressure has dropped 3.6 lbs this week to 18 lb. The sugar content has advanced to an exemplary 14 °Bx. The taste is excellent for this variety too.
Fuji (Aztec®)
Aztec Fuji closing in on maturity in Centre County. The sugar content (13.4 °Bx) is great, but the starch index value (3.1) and pressure (19.2 lb) still need to time to advance. We will continue to monitor Aztec Fuji in the next few weeks.
Crimson Crisp®
Crimson Crisp has excellent color and sugar accumulation and is coming into its maturity window now. The advanced starch index value (6.7) gives the fruit time to develop flavor on the tree, which is supported by the continuing high pressure (21.0 lb) of the fruit. The outstandingly high 14.6 °Bx supports the crisp and sweet flavor. Keep a close eye on Crimson Crisp to balance flavor development with high starch index levels this week. Consider that this variety may not store long term optimally with overmature starch levels.
Conducting Maturity Tests at Home
While this article series points to trends across the state, it provides data from only three counties. Because of this, conducting tests locally can provide specific information to best guide harvest timing. This article on determining fruit maturity and optimal harvest dates has information on the hows and whys behind maturity metrics. Please consider reading the article before interpreting these reports, as it can better explain why each metric is used. It also describes the tools used, some of which are available for modest prices (such as a basic penetrometer), which can support your own maturity testing methods.
Iodine Starch Indexing
Iodine testing and starch index scales are a user-friendly approach to collecting maturity information. The starch iodine index values in these reports are estimated using an excellent new resource from Michigan State University. A PDF version of the booklet is available for free, and printed copies may be available from a local Extension office. Please be aware that the (largely inert) chemicals used in the staining process are no longer available over the counter and require authorization from the federal government to purchase. For information on how to acquire them, contact the authors.
Controlling Harvest Timing
Stop-drop materials are widely used to delay fruit ripening. There are a number of stop-drop products available for use in Pennsylvania. These chemicals, including ReTain®, Harvista™, and NAA products, all interfere with ethylene production in apples. Controlling the harvest window can be beneficial for U-Pick operations by expanding the accessibility of highly desirable varieties into the peak fall season. Stop-drops can also be implemented to manage the workflow of orchard crews to ensure that more apples are harvested at peak ripeness. Additionally, delaying harvest can allow for longer exposure to better weather for color development.
Reference Data
The data reported above may be compared against the following previously published information. Consulting these tables may be useful when making decisions about optimal storage time based on your storage requirements.
| Mass (g) | The mass (commonly "weight") of the fruit in grams. Despite measurements being taken using SI units (metric), most are converted to the units common in the US. This is the one exception. To convert to ounces, divide grams by 28.3 (or round up to 30 g/oz for a close estimate.) |
| Diameter (in) | The maximum width of the apple as measured across the cavity. |
| Color (%) | The visual percentage of red color from 0 to 100%, indicating the surface area covered in red coloration and the intensity of red coloration. |
| Background Color | 5 = green, 1 = yellow. Background color evaluated against the standard found in Simons, L.R. (1948) Ground Color for McIntosh Apples, Cornell Extension Bulletin, Number 750, last accessed July 29, 2024. |
| Firmness (lb) | Pounds of pressure was measured using a handheld FT 325 Penetrometer (Berks, Centre) or a Güss Fruit Texture Analyzer (Adams). |
| Starch Index | 1 = 100% starch, 8 = 0% starch. Starch indices evaluated against standards found in Beaudry, R. et al. (2023) Starch Index Scale, Michigan State Extension, last accessed July 29, 2024. |
| Brix (°Bx) | Degrees Brix, a measure of soluble solid content ("sugar") in apple juice equivalent to 1 g of sucrose dissolved in pure water to form 100 g of solution. Measured with an Atago PAL-1 Pocket Refractometer (Adams, Centre) or a Fisher HDR-P1 handheld digital Brix/RI refractometer (Berks). |
| Variety | Short CA | Mid-CA | Long CA |
|---|---|---|---|
| Early Fuji | 16 | 17 | 18 |
| Empire | 14 | 15 | 16 |
| Fuji | 16 | 17 | 18 |
| Gala | 16 | 17 | 18 |
| Golden Delicious | 15 | 16 | 17 |
| Honeycrisp | 15 | 16 | 17 |
| Idared | 14 | 15 | 16 |
| Jonagold | 15 | 16 | 17 |
| Jonathan | 14 | 15 | 16 |
| McIntosh | 14 | 15 | 16 |
| Red Delicious | 16 | 17 | 18 |
| Rome | 15 | 16 | 18 |
| Variety | Mature | Over-mature |
|---|---|---|
| Early Fuji® | 3 | 7 |
| Empire | 3.5 | 6 |
| Fuji® | 3 | 7 |
| Golden Delicious | 3 | 6.5 |
| Honeycrisp | 3.5 | 6 |
| Idared | 3.5 | 6 |
| Jonagold | 3.5 | 5.5 |
| Jonathan | 3.5 | 5.5 |
| Red Delicious | 2.5 | 6 |
| Rome | 3 | 5.5 |
| Low | Fair | Good | Excellent | |
|---|---|---|---|---|
| All Varieties | < 11 | 11 | 12 | 13 |
| Honeycrisp | < 12 | 12 | 12 | > 14 |
Conclusions
Commercial fruit growers, please note: apple maturity conditions need to be monitored at a local level within one's own orchard. Before chemical products are applied, be sure to comply with current federal, state, and local usage regulations and examine the product label. Product information can be easily obtained online from CDMS.
This series of updates is made possible by a State Horticultural Association of Pennsylvania (SHAP) Extension Grant (Pennsylvania Apple Maturity Program). The authors thank SHAP for the funding and thank the growers participating in these updates and allowing access to their orchards to sample fruit.
