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Low Temperature Damage to Peaches, Nectarines in Rock Springs, PA

In January 2025, temperatures at Rock Springs, Pennsylvania Furnace, PA, dropped to -12°F for more than an hour, damaging tree buds and potentially affecting the upcoming growing season.

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Updated:

March 21, 2025

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Mid-winter damage to 1-year old peach and nectarine orchard at Rock Springs, PA

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On January 22^nd, 2025, temperatures at Rock Springs, Pennsylvania Furnace, PA, dropped to -12°F for more than an hour (Figures 1 and 2), damaging peach and nectarine buds and potentially affecting the upcoming growing season. Cold temperatures were also observed in other growing regions such as Adams County, Lancaster, Pittsburgh, and Erie. Mid-winter cold damage remains a challenge for Pennsylvania peach and nectarine growers, particularly during severe cold snaps. To assess the impact, we collected peach and nectarine shoots from 1-year old trees that were planted in spring 2024, incubated them in room temperature for 48 hours, and analyzed bud damage in Red Haven peaches and Avalon nectarines (Figure 3).

Figure 1. Daily air temperature data for January 2025, including maximum (Max), minimum (Min), and average (Avg) temperatures. The lowest recorded temperature occurred on January 22nd (-11.9℉), followed by January 21st (-8.5℉).(All Weather Data Query | NEWA, n.d.)

Average hourly air temperature on January 22nd, 2025, the coldest day recorded in the current year. (All Weather Data Query | NEWA, n.d.) — Figure 2. Average hourly air temperature on January 22^nd, 2025, the coldest day recorded in the current year. (All Weather Data Query | NEWA, n.d.)

Cold Damage Assessment: Data from the Orchard

Peach ('Red Haven') Bud Damage

Branches Assessed: 10
Total Buds: 137
Damaged Buds: 47
Damage Percentage: 34.3%

Nectarine ('Avalon') Bud Damage

Branches Assessed: 10
Total Buds: 184
Damaged Buds: 78
Damage Percentage: 42.4%

Nectarines sustained more damage than peaches, consistent with their higher sensitivity to cold temperatures. Damage percentages (34.3% for peaches and 42.4% for nectarines) are within expected ranges for a cold event with temperatures reaching a low of -12°F, where bud mortality typically ranges from 30% to 50% (Figure 3). No bark/stem tissue damage was observed.

Shoots collected from the field for bud mortality estimation 3B,C: Cross-section of freeze-damaged buds with black and brown patches indicating dead tissue. 3D: Healthy bud tissue. — Figure 3. Shoots collected from the field for bud mortality estimation **3B,C:** Cross-section of freeze-damaged buds with black and brown patches indicating dead tissue. **3D:** Healthy bud tissue.

Table 1. Typical critical temperature for mid-winter damage to fruit buds for varieties adapted to Pennsylvania temperatures.
Fruit Type	Temperature (F)
Apple	-30
Apricot, pear, concord grape	-25
Blueberry	-25
Tart cherry	-20
Raspberry	-17
Blackberry	-15
Plum, sweet cherry	-15
Peach and nectarine	-13
European grape	-8 to -15

Apart from the duration and exposure to the cold event, the vulnerability of dormant peach and nectarine trees to freeze damage is also determined by the rate of temperature change (cooling and warming), and frequency and magnitude of temperature fluctuations. These factors, combined with tree health and dormancy stage, collectively influence the extent of cold injury. Thus, the entire thermal profile of a frost event, rather than just the absolute minimum temperature, is crucial in assessing potential damage to dormant trees.

Ways to Assess Bud Damage

To properly assess freeze or cold damage in peaches, collect shoots with flower buds and incubate them at room temperature (around 70°F) for 24–48 hours. After incubation, cut through the buds longitudinally and check for browning or blackening of the pistils or ovules, which indicates tissue death and potential crop loss.

Avoid placing the shoots in water to observe bloom, as damaged buds may still bloom but often fail to set fruit due to damaged reproductive parts.

Practices to Help Cold-Damaged Peach and Nectarine Trees in Pennsylvania

Pruning Guidelines

When pruning peach and nectarine trees, maintain a moderate approach and avoid intense pruning, especially while the trees are recovering from cold injury. Limit large cuts on the lower scaffolds to reduce unnecessary stress.

Refrain from pruning between September and early January because trees, particularly mature peach trees, become less winter hardy when pruned during this period. Additionally, heavy summer pruning depletes carbohydrate reserves, making trees more vulnerable to winter damage. However, dead limbs can be safely removed at any time.

Managing Tree Height

Avoid aggressive pruning to reduce tree height in years without a crop, especially if the tree's overall health is compromised. Hedging the tops of trees to manage height is too severe and can weaken the tree. Instead, selectively cut upright limbs back to strong side branches to maintain control over top growth while preserving tree vigor.

Nutrient and Water Management

Modify nitrogen application rates based on the crop load—trees with little or no crop need less nitrogen.

Keep an eye on annual shoot growth to assess tree health. Growth of less than 1.5 feet increases susceptibility to canker and winter damage, while excessive growth exceeding 2.5 feet increases the risk of fall cold injury.

Ensure adequate soil moisture, especially on sandy sites, by providing irrigation when conditions become dry.

Long-Term Orchard Strategy

Develop a regular schedule for orchard renewal to maintain a balance of different tree ages. Varying tree ages help buffer the impact of harsh winter conditions across the orchard, ensuring a more consistent production cycle. Implement tree training techniques during the early years to reduce the need for large corrective cuts later, especially on the lower scaffolds.