Weather summaries are included in this week's update along with the first Honeycrisp fruit maturity report from the example regions. Maturity updates are meant to indicate the rate of change of ripening each week and, when possible, will be compared to past years. The Orchard Outlook Committee has resumed meeting for harvest and their recommendations are included.
Total degree day accumulations are similar to the 5-year average and slightly warmer than the 10-year average (Figure 1). Harvest dates are difficult to predict based on degree day accumulations alone. Given that this year has been among the warmest growing seasons on record, it's likely that harvest will be on the early side and should be monitored closely. Use harvest dates from similarly early years as estimates and leave a comfortable buffer for preharvest intervals with fungicides and insecticides.
Figure 1: Heating degree day accumulations for plant (above 5°C) and insect (above 10°C) development from March 1 to August 31 for the past 17 seasons. Provided by Harrison Wright (AAFC).
Precipitation
We are continuing our sawtooth pattern of alternatively being either well above or well below the precipitation monthly averages in Kentville. Actual precipitation varies based on region. Although August felt rainy, many rain events were short duration and ultimately added up to less than average precipitation.
Figure 2: Monthly precipitation totals in 2026 (triangles) compared with the 25-year average (bar graphs). Provided by Harrison Wright (AAFC Plant Physiology).
Honeycrisp Fruit Maturity Report
- Continuing this year, Perennia will give short weekly updates as indicators of Honeycrisp and Ambrosia maturity.
- Sampling begins early to track the rate of change leading up to harvest.
- Fruit representative of size and colour for a first pick were taken from all sides of the canopy (not from the interior of the canopy where maturity is expected to be delayed and is most likely targeted for a second pick timing).
Current Maturity (Aug 31 to Sept 1, 2026)
Table 1: Maturity indices for regular Honeycrisp fruit sampled in the current year on Aug 31, 2026 in Rockland (16 yr trees) and Lakeville, and Sept 1, 2026 in North Medford and Rockland (8 yr trees).
Current Maturity - Table 1 Discussion:
- The starch has not yet started to convert to sugars so all Honeycrisp fruit are at the highest starch rating of 1.0.
- Soluble solids values in our region for Honeycrisp tend to be 11% brix at harvest maturity but it depends on many factors including crop load. Values for this time of year appear normal.
- The average DA value ranges from 1.08 to 1.14. It is still too early to predict harvest dates with any degree of accuracy.
- Overall, the maturity is similar between locations and blocks - unlike last year during the drought when there was extreme variation between locations.
Historical Comparison
Table 2: Maturity indices for regular Honeycrisp fruit sampled on Aug 31 and Sept 1 relative to a similar calendar date in the 2024 season. The measurements from 2025 are not used for comparison because of the influence of extreme weather conditions. The new Rockland site has no historical measurements for comparison.
Historical Comparison - Table 2 Discussion:
- High DA meter values are less mature. So far, the DA meter values suggest that fruit maturity is not as far advanced this year as it was during the very early year 2024.
- Starch does not convert to sugar this early so any differences are not yet observable.
- Soluble solids are close to 2024 values.
More Observations
The following information is highly dependent on the crop load in a particular block:
- There is less vibrant red colour development now than there was at this same time during a good colour year like 2024 (Figure 3). Local study data suggests red blush coverage should be around 15-20% at this time of year.
- Recent cool nights of around 11°C and 13°C will improve colouration.
- Strategies for colour enhancement should go ahead as planned.
- The fruit mass in my samples averaged 185 g, which is normal for this time of year based on local study data. Average weight ranged from 162 g to 218 g.
- The fruit diameter averaged 75.8 mm (3 inches). In general, Honeycrisp is approaching the start of ideal fruit size and with several weeks yet to grow. Average diameter ranged from 73 mm to 81 mm.
Figure 3: The blush red colour side of ten-fruit samples from three regions in 2024 versus 2026. Sampled fruit are from the outer canopy that would be targeted for a first pick.
About each maturity measurement:
Starch Index - Starch is converted to sugars as ripening progresses. The starch-iodine test is used because iodine binds to starch molecules turning them blue/black, whereas sugars are not stained and remain clear. The Cornell chart on a scale of 1 to 8 was used above and values are an average of ten representative samples from each block.
Soluble Solids - Approximates the percentage of sugar content of the fruit. Measured using a digital refractometer. Values are an average of ten representative samples from each block taken on the blush side of each fruit. Soluble solids values in our region for Honeycrisp tend to be 11% brix at harvest maturity.
DA Meter - The delta absorbance (DA) value is related to the chlorophyll content of the peel. AAFC researchers in Kentville developed a protocol for Honeycrisp. Values above 0.60 are immature, values 0.6 to 0.36 are ideal for long term storage, and values below 0.35 are best for short term storage because they are more prone to storage disorders. Values shown above are the average of twenty fruit taken throughout a block, with readings taken on the transition area between the sun and shade exposed sides. DA values will be noticeably different between the most mature and least mature fruit on a tree.
Using Iodine Solution for Maturity Testing
For those of you doing your own iodine testing please note:
- Generic iodine chart created for McIntosh is used as guidance.
- Consult your packinghouse for suggested starch index values used to determine the first acceptable harvest date of specific apple varieties.
- Local research by John Delong et al. 2013 and 2016 showed that optimal values for long-term storage are as follows: Honeycrisp between index 5.0 and 7.5 and Ambrosia between index 2.8 and 5.0
- The correct starch-iodine index numbers for the first acceptable harvest date will vary depending on region so be careful of numbers that you use from other regions. Typically more northern regions such as ours will have relatively higher starch index values than southern apple growing regions for the first acceptable harvest date because low temperatures preceding harvest favour the conversion of starch to sugar.
- Charts for varieties are available online but please note that the generic chart is the industry standard. The variety-specific charts just tend to show the variety-specific pattern of starch staining better than the figures developed using McIntosh. Just be cautious of the index values they report for long-term storage.
Other Reminders
- ReTain has shown good local results with preventing fruit tackiness, cracking, and greasiness.
- This year more shoot vigour has resulted in more shading. Summer pruning can offer a big benefit, especially on vigorous rootstocks.
- Plan for getting land ready for next year if you are planting in spring. This includes getting herbicides on, working the ground, ripping rows, adding phosphorous, and applying limestone.
- In nurseries with large trees and good growth, do a final tie with rubber tree ties instead of max tapener. The max tapener can break under snow load whereas a rubber tie is more durable and can make a big improvement in tree survival.
- Perform weed control in nurseries and apply herbicide at nursery borders to remove rodent cover.
This Orchard Outlook has been published with the input of the Orchard Outlook Committee including this week's contributors: Danny Davison, Harrison Wright, Larry Lutz, Joan Hebb, Bob Prange, Colin Hirtle, and Jill MacDonald.
Perennia Food and Agriculture Corp.
Edited by Michelle Cortens, Tree Fruit Specialist
Edited by Michelle Cortens, Tree Fruit Specialist
