Sour Cherry: CropAid AntiFrost protected 70-80% from Advective frost despite 3 days at -7, -9 and -5 Celsius in Hungary
Posted on: February 12, 2026 • Posted in: Trial Results
🍒 Sour Cherry: CropAid AntiFrost protected 70-80% from Advective frost despite 3 days at -7, -9 and -5 Celsius in Hungary 🍒
Typical Risk vs Actual Observation In
Érdi bőtermő Sour Cherry Orchard
🌱 Report by Dr. Jozsef Csepeli – www.CropAid.hu/
| Key Point | Typical Risk at These Conditions | Actual Observations |
|---|---|---|
| Stage during frost | At bloom, even –1 to –2 °C can cause serious damage. Below –6 °C not tolerated even in bud. | Frost hit at 40–50% bloom during –7, –9, –5 °C. |
| Damage visibility | Damage shows 2–3 weeks before ripening, after color change. | Remaining flowers appeared favorable after assessment. |
| Fruit shedding risk | Trees may shed up to half the fruit. | 10–15% pre‑harvest drop. |
| Expected fruit loss | Serious damage expected below –6 °C. | Frost loss 20–30%; fruit set relatively successful. |
| Nutrient condition | Cold stress can show up as deficiency symptoms. | No nutrient deficiencies observed. |
| Shoot growth | Severe frost can limit growth. | Intensive shoot growth; 3 m rows closed early, 5 m rows met in places. |
| Ripening pattern | Frost can cause irregular ripening. | Uniform ripening; no selective picking needed. |
| Harvest window | Damaged crops may have shortened harvest period. | Fruit stayed suitable for harvest for a long time. |
| Yield | Severe frost commonly reduces yield. | 30 kg/tree; 10 t/ha vs area 5–7 t/ha. |
| Quality & market | Frost can reduce taste and size. | Outstanding flavor; 22–24 mm; 30% sold fresh with continuous orders. |
The orchard in which CropAid AntiFrost® was tested is an Érdi bőtermő sour cherry plantation established in 2015, with a spacing of 5 × 3 meters. The original goal at planting was to achieve 20 kg per tree, with an orchard layout suitable for both hand harvesting and mechanical shaking.
Sour cherry is generally less sensitive to frost; however, frost during flowering can cause serious damage even at –1 to –2 °C. This damage does not appear immediately but becomes visible 2–3 weeks before ripening, as colour change begins, when trees may shed up to half of their fruit.
To mitigate frost damage, CropAid AntiFrost was applied twice—on March 20 and April 4, 2025—at 4 L/ha with 700 L/ha water using an axial fan sprayer. The product’s low pH (~2) required careful adjustment: 350 ml phosphoric acid was added to well water (pH 7.5) to reach pH 4–4.5. Application occurred at 8–10 °C during midday.
The frosts were advective (polar) with winds of 10–15 km/h.
- April 7: –7 °C, long duration (–2 to –3 °C still at 7–8 a.m.)
- April 8: –9 °C, lasting a long time
- April 9: –5 °C, mildest but caused most visible regional damage
The orchard was at 40–50% bloom, and sour cherry does not tolerate below –6 °C even in bud stage.
After frost passed, rapid warming required immediate action. Remaining flowers appeared favourable on inspection. To reduce the likelihood of fruit shedding (even with green pistils), amino acids were applied.
Bee colonies ensured pollination, and an extra dose of boron supported fruit set. Despite cold conditions, fruit set was relatively successful, and frost loss was limited to 20–30%.
No nutritional deficiencies appeared.
Foliar fertilizers (5 L/ha) were added through the season. Intensive shoot growth occurred: the 3 m in‑row spacing closed by early May, and even 5 m tractor rows met in places.
Pre‑harvest drop was moderate at 10–15%. From June 20, the crop appeared ready.
Fruit ripened uniformly—no selective picking required—and remained in good condition for an extended harvest window.
As industrial prices exceeded €2, 60–70% of the crop was mechanically harvested. Despite frost signs, yield reached 30 kg per tree. Érdi bőtermő is known for flavour, but this season’s taste was described as particularly outstanding. Consumers purchased 30% of the crop fresh, with continuous orders. Fruit size reached 22–24 mm.
Nearby orchards achieved 5–7 t/ha; this orchard produced 10 t/ha.
🍇 Summary 🍇
Despite three severe advective frost events at –7, –9 and –5 °C during bloom, the orchard achieved strong fruit set, moderate drop, excellent quality, and a yield significantly higher than surrounding orchards. Intensive vegetative growth, uniform ripening, and high fresh‑market demand highlighted the season’s performance.
CropAid AntiFrost (with correct pH adjustment), together with amino acids, boron, and good pollination, coincided with a productive outcome under unusually harsh conditions.
Do you have effective frost, cold, heat and drought protection? Do you wish to increase yield, marketing qualities etc?
Contact CropAid | Frost and Heat Protection for Crops
