With more than 25 years of experience, agronomist Gerardo Aldunate partners with Index Fresh growers to advance best practices and deliver efficient, high-quality production. We sat down with Gerardo to get his expert insights on proactive planning for the cold season and how to approach fertilizer decisions, frost protection, and irrigation maintenance.
Question: What information do growers need to prepare for next year’s fertilizer inputs?
Answer: Recordkeeping is key to building an effective fertilizer plan. Historical records like leaf and soil analyses, irrigation data, and yield performance help guide decisions for the upcoming season.
- Review your 2025 fertilizer program, leaf analyses, yields, and size curves.
- Identify underperforming blocks and high-performing areas. Use these insights to adjust management practices.
- Inspect tree health by observing leaf color (dark green to yellow), leaf size (large to small), and any salt burn. These observations, combined with cultural records, can help fine-tune nutrient and root health programs.
Q: Some growers are worried about frost damage. How can they prepare for winter frosts?
A: A few key steps can significantly reduce frost risk:
- Inspect and service wind machines for frost protection.
- Enhance natural air movement by pruning or trimming where necessary.
- Improve drainage to prevent waterlogging.
Stay alert by monitoring weather forecasts. Here are links to several reliable sites that help anticipate weather events: WeatherWest, National Weather Service, Ventura County Public Works, Weather Underground.
Q: We’ve heard concerns about excess water and root rot. What should growers do?
A: Avocados are highly sensitive to saturated soils, just 24 – 48 hours of flooding can cause severe root damage from oxygen deprivation. After heavy rain, inspect your ranch for poor drainage areas and take prompt action:
- Improve drainage where possible by digging channels to move water away quickly. Remember that Phytophthora root rot thrives in cool, wet conditions. Prolonged cloudy weather reduces photosynthesis, weakening trees and increasing susceptibility.
- Depending on tree conditions, consider early spring treatments with phosphorous acid and/or fungicides.
Q: What should growers do for irrigation system maintenance?
A: If they work with a grove management company, confirm their winter irrigation maintenance and upgrade plans. For self-managed systems, follow these steps for effective upkeep:
- Check pressure: Ensure uniform system pressure; repair leaks or broken sprinklers.
- Clean filters: Remove clogs from organic matter or mineral buildup. Replace filters if needed.
- Clean emitters and flush lines: Clear blockages and sediment build up from drip lines, following UCANR recommendations.
- Check controllers: Verify system functionality and adjust irrigation schedules as necessary.
Sources: Newett, 2021; California Avocado Commission, UCANR
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About Gerardo Aldunate
Gerardo Aldunate is a leading agronomist with experience working with avocado producers worldwide. Aldunate advises Index Fresh’s avocado partners and participates across the California avocado industry, providing education in conjunction with the California Avocado Society and California Avocado Commission.