2025 Pennsylvania Tree Fruit Maturity Report - September 9

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 weather is excellent for coloring in Adams County this week with mostly sunny conditions, high temperatures in the low 80°F and low temperatures in the 50°F. Overall, this has been a wonderful year for coloring due to the cool weather in the past month and Pennsylvania Honeycrisp has colored well.

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.

CrimsonCrisp®

CrimsonCrisp® has reached full maturity and is ready for immediate harvest across all market segments. Fruit quality is excellent, with an average mass of 186 g and a diameter of 3.0 in. The variety shows exceptional red coloration at 94%, reflecting strong visual appeal. Firmness is very high at 23.8 lb, providing excellent storage potential and eating quality. The starch index of 6.0 indicates near-complete starch conversion, and soluble solids have reached 14.0 °Bx, promising a sweet and balanced flavor. This variety should be harvested without delay to ensure optimal quality and prevent overripening.

Crown™ Empire

Crown™ Empire is showing good progress toward maturity, though it remains slightly ahead of Red Delicious and just shy of full readiness. Fruit size is solid, averaging 2.9 in and 158 g, with excellent red color development at 92.5%. Firmness is at 20.5 lb. The starch index has reached 4.3, indicating that the fruit is entering the harvest window but could benefit from a few more days on the tree, particularly for fresh market use. Soluble solids are moderate at 12.2 °Bx. Crown™ Empire may be harvested now for longer-term storage, but for the best quality and flavor, harvest for direct market use might be better timed for late this week or early next.

Golden Delicious

Golden Delicious is now within the optimal harvest window in Adams County. Fruit size remains excellent, averaging 3.3 in in diameter and 267 g in mass. Pressure has declined slightly to 18.4 lb. The starch index has climbed to 4.1, showing significant advancement from the previous week and confirming maturity progression. Soluble solids remain high at 13.2 °Bx, indicating good flavor development. Golden Delicious should be harvested immediately if destined for long-term controlled atmosphere (CA) storage or processing. If intended for fresh market or short-term air storage, harvest can extend over the next week, but delaying much longer may risk over-maturity.

(Red) Jonaprince

Jonaprince is approaching harvest maturity and is suitable for fresh market harvest in the coming days. Fruit are notably large, averaging 332 g and 3.7 in in diameter, with red color coverage at 61.5%—a moderate level for this variety. Firmness has declined to 17.2 pounds, which, while lower than some other varieties, is still acceptable for retail quality. The starch index is at 5.8, suggesting that the fruit is nearing full maturity. Soluble solids are at 12.3 °Bx, providing adequate sweetness. Jonaprince may not be ideal for long-term storage at this stage, but is a good candidate for immediate harvest and short-term storage or fresh consumption.

Ludacrisp®

Ludacrisp® continues to ripen and is approaching its optimal harvest window. The fruit are well-sized, averaging 3.2 in in diameter and 242 g in mass, with firmness at 19.0 lb -appropriate for both fresh use and short-term storage. The starch index has advanced to 4.9, and soluble solids are at 13.0 °Bx, indicating good flavor potential. However, red color development remains low at just 8.0%, which may limit visual appeal, particularly in direct retail markets. Growers should continue to monitor Ludacrisp® closely over the next two weeks. As this variety develops more flavor with maturity and is primarily marketed through direct-to-consumer channels, it can be harvested at a higher starch index—around 6—unlike other cultivars that are often harvested earlier to preserve storability.

Red Delicious (Super Chief® / Sandidge cv.)

Red Delicious continues to mature steadily in Adams County. Red color coverage is now excellent, averaging 95%, with good fruit size (3.3 in) and increased average mass at 264 g. Firmness is holding strong at 19.2 lb, while the starch index has improved slightly to 3.4, suggesting that starch conversion is gradually progressing but not yet complete. Soluble solids are at 11.7 °Bx, consistent with early-stage sweetness. Growers targeting long-term CA storage may begin harvest now, while those aiming for short-term storage or fresh market may prefer to wait another 7 to 10 days for further starch degradation and enhanced flavor.

Berks County

Maturity samples were collected from two orchards in Boyertown; please adjust harvest decisions based on specific local site conditions.

Golden Delicious

Golden Delicious is nearing full maturity in Berks County, with clear signs of advancement in both internal and external quality over the past week. The fruit diameter has increased slightly to 2.4 in. The background color has shifted from 3.0 to 2.3, indicating continued ripening and chlorophyll loss. Flesh firmness has decreased to 15.9 lb, a significant drop from 17.3 lb the previous week, and a strong indicator that the fruit is entering the mature range. The starch index has climbed from 2.7 to 3.6, suggesting ongoing starch degradation, while soluble solids have also increased from 11.8 to 12.3 °Bx, reflecting improved flavor and sugar accumulation. Based on these indicators, Golden Delicious is approaching its ideal harvest window. Fruit for long-term CA storage should be harvested soon, while those destined for short-term storage or fresh market may benefit from another few days on the tree to enhance eating quality.

Red Delicious

Red Delicious is steadily progressing toward full maturity. The most recent sampling on September 8 shows continued improvement in both size and internal quality. Fruit now averages 2.3 in in diameter and 174 g in mass—an increase from last week—while red color has reached an excellent 97.5%, providing strong visual appeal for market. Flesh firmness is at 18.6 lb, showing a slight softening but still well within the desirable range for storage. The starch index has risen slightly to 2.9, indicating slow but ongoing starch conversion. Soluble solids have increased to 11.4 °Bx, reflecting improved sweetness. While the variety is not yet fully mature, it is approaching the harvest window. Fruit intended for long-term CA storage should be monitored closely and may be harvested soon. For short-term storage or fresh market use, harvest may be better timed for the next 7-10 days, allowing further starch degradation and improved flavor.

Centre County

Maturity samples were collected from one orchard in Centre County; please adjust harvest decisions based on specific local site conditions.

Ambrosia (DT2 cv.)

Ambrosia is not mature in Centre County this week. The high pressure (20.6 lb) and low starch index value (1.2) will give the already good sugar accumulation at 11.9 °Bx time to develop over the next few weeks.

Fuji (Aztec®)

Aztec Fuji® is not mature in Centre County. The sugar content (11.8 °Bx) and color will have time to develop as the pressure (20.8 lb) and starch index value (1.9) over the next few weeks.

Gala (Brookfield®)

While Gala pressure is still fairly high at 17.5 lb, the starch index is now well progressed. The taste and color of these apples are excellent. This variety is being harvested this week in Centre County.

Honeycrisp (Royal Red®)

Royal Red Honeycrisp® firmness has held at 13 lb, which suggests ongoing softening. The starch index values have developed to 6. The sugar content is now excellent at 13.6 °Bx. This variety is being harvested this week in Centre County.

RubyMac® (B. Thome Mac cv.)

RubyMac® apples have the typical beautiful blush in Centre County and are currently mature with an exceptional sugar accumulation of 13.6 °Bx. Consider tracking this variety closely this week.

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.

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.