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Preparing California Avocado Groves for Winter

Posted: September 24, 2013

Because avocado trees are tropical rainforest trees, they are active year-round — and that means cultural management of avocado groves is necessary throughout the year. While winter is a good time to assess the most recent avocado production, the status of avocado trees and spring bloom setup, growers should utilize the autumnal months to prepare avocado groves for winter weather events, flush out accumulated salts, and apply pruning techniques and fertilization for optimal spring performance.

Freeze protection

  • Assess potential airflow in your groves. Cold air drainage is critical to preventing damage to trees during winter freezes, so look for troublesome areas that prevent easy air flow and conduct light pruning that enhances air circulation in the lowest portions of your grove.
  • Service wind machines and irrigation systems to ensure they are ready for the winter season.

Fertilization

  • Collect spring flush leaf samples for nutrient analysis. Work with your grove manager or farm advisor to examine the analysis in the context of your specific grove — the most recent crop harvested, the fruit set for next year and the bloom potential.
  • If necessary, amend the nutrients with a lower-rate winter fertilization taking care not to apply too much nitrogen that can stimulate a frost-sensitive growth flush.

Pruning

  • Assess avocado trees’ crop loads and summer flush to determine whether these factors will place your trees into an alternate bearing cycle.
  • If necessary, thin a heavy crop with a light pruning that does not lead to a frost-sensitive autumnal growth flush.

Irrigation and salinity management

  • Flush accumulated summer salts from avocado grove soil with leaching irrigations before the winter rains.
  • If necessary, irrigate your groves after the first few winter rains in order to dilute and leach salts that the rain puts back into solution in the root zone.

For further information, read Preparing for Winter in the upcoming Fall 2013 issue of From the Grove.