2025 Pennsylvania Tree Fruit Maturity Report - September 30
Crimson Crisp® in the early morning fog in Centre County. Photo: Copyright © 2025 Lindsay Brown and Penn State.
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
Southeast Pennsylvania will have perfect coloring weather this week with warm days (highs ranging from 70 - 84°F) and cool nights (lows ranging from 45 – 57°F). Some rain showers are expected on October 7th and 8th, but we can expect a return to the beautiful and sunny fall weather. This fall continues to support excellent apple production in Pennsylvania.
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.
- Presentations available from 2024 Controlled Atmospheric Storage Clinic
- Above includes research on Ambrosia, EverCrisp®  Gala, and Honeycrisp storage practices and physiological disorders.
- Fruit Disorders- Practices to Manage Storage Disorders in Honeycrisp
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.
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) |
|---|---|---|---|---|---|---|---|
| EverCrisp® | |||||||
| 9/28 | 244 | 3.2 | 47 | 2.65 | 24.4 | 4.9 | 16.7 |
| Fuji (Aztec®) | |||||||
| 9/28 | 245 | 3.3 | 58.5 | 2.2 | 18.3 | 5.2 | 14.8 |
| 9/21 | 197 | 3.0 | 48.0 | 2.2 | 19.8 | 3.3 | 14.2 |
| Nittany | |||||||
| 9/28 | 251 | 3.4 | 58.5 | 2.4 | 19.8 | 2.8 | 13.1 |
| 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 |
EverCrisp®
EverCrisp® is quickly becoming mature in Adams County. While the pressure is still quite high (24.4 lb), the starch index value (4.9) and very high sugar levels (16.7 °Bx) indicate that this variety is one to watch this week. The high pressure can give the fruit time for increased color development. However, the advanced starch levels should be watched closely. Of note, these samples had water core. This is not shocking considering the high sugar levels. Please see this resource from MSUE on water core. Consider the water core when making long-term storage decisions.Â
Fuji (Aztec®)
Aztec® Fuji is moving towards over-maturity in Adams County. These apples have excellent sugar accumulation (14.8 °Bx), and the starch clearing is running towards over-maturity for long-term storage (5.2). The pressure is still holding firm at 18.3 lb, which will give time for the blush color (48%) to develop in the next week. Based on how quickly the starch clearing is progressing, these apples should be harvested in the area in the next week or two.
Nittany
Between the lower starch index value at 2.8 and the higher fruit firmness at 19.8 lb this week, Nittany is not currently ready for harvest. However, it should be watched in the next two weeks. The sugar content is still at 13.1 °Bx. This great sugar content and coloring should only increase as the Nittany apples continue to mature.
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® | |||||||
| 9/29 | 234 | 2.57 | 64 | 1.0 | 19.9 | 4.4 | 15.8 |
| 9/22 | 214 | 2.6 | 50 | 2.0 | 20.4 | 5.8 | 15.1 |
| Fuji (Aztec®) | |||||||
| 9/29 | 177 | 2.3 | 59 | 1.3 | 17.4 | 5.1 | 13.7 |
| 9/22 | 163 | 2.3 | 55.5 | 2.1 | 18.1 | 2.8 | 12.9 |
| Granny Smith | |||||||
| 9/29 | 213 | 2.5 | 19.8 | 3.4 | 19.2 | 2.5 | 11.7 |
EverCrisp®
EverCrisp® is mature in Berks County. While the firmness for EverCrisp® is still high (19.9 lb), the starch index value (4.4) and sugar accumulation (15.8 °Bx) are quite progressed. 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. Â
Fuji (Aztec®)
Fuji (Aztec®) are now mature in Berks County. The starch index value has increased from last week (2.8 to 5.1) and the pressure is continuing to drop (17.4 lb). The sugar content also developed last week and is now at 13.7 °Bx.
Granny Smith
Granny Smith apples are not yet mature in Berks County. The high pressure (19.2 lb) will give the sugar content (11.7 °Bx) and starch index values (2.5) time to develop. This variety will become mature in the next couple of weeks.
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) |
|---|---|---|---|---|---|---|---|
| Fuji (Aztec®) | |||||||
| 9/29 | 177 | 2.8 | 56.0 | 2.0 | 19.5 | 3.5 | 14.5 |
| 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 |
| Nittany | |||||||
| 9/29 | 197 | 2.9 | 61 | 1.9 | 19.5 | 2.9 | 13.6 |
Fuji (Aztec®)
Fuji (Aztec®) is closing in on maturity in Centre County. The sugar content (14.5 °Bx) is excellent. The starch index value (3.5) and pressure (19.5 lb) still need time to advance, indicating that this variety can be harvested for long-term storage at this point. However, it could be kept on the trees for longer for flavor and color development if growers are planning for short-term storage. We will continue to monitor Fuji (Aztec®) in the next couple of weeks.
Nittany
Nittany apples are near maturity in Centre County this week. The flavor, background color, and red coloration will continue to develop as starch (2.9) and pressure (19.5 lb) progress. The sugars are already very strong (13.6 °Bx) and will be even better once the fruit reaches full maturity.
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 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.
