West central Michigan small fruit report – April 23, 2024

The blueberry bloom period just started in west Michigan but weather conditions still possess some risk of spring frost damage.

Two different blueberry varieties.
Figure1. Blueberry varieties at different bloom stages on April 23, 2024, in Allegan County, Michigan. Left, Bluecrop at 1 inch green stage and early pink. Right, Elliott at tight cluster stage. Photos by Carlos Garcia, MSU Extension.

The blueberry bloom period just started in west centra Michigan. Days of low temperatures alternated with warm days advanced the bloom period more than one week ahead in relation to 2023. However, current weather conditions characterized by temperatures in the low 70s with cold nights reaching in some areas 30 degrees Fahrenheit have kept plant growth and development in check. So far, no major problems have been reported by blueberry growers, although the situation for other fruit crops like grape is not very good since early warm temperatures followed by temperatures below 30 degrees Fahrenheit ruined early varieties, especially in southwest Michigan.

As of April 23, most blueberry fields in west Michigan are in different stages of development. Varieties like Brigitta, Bluetta and Bluecrop are at 1-inch green, and flower buds are in the late pink stage. At the same time, the late-season variety Elliott is at the tight cluster stage (Figure 1).

Weather conditions are rapidly changing, and we are expecting some spring frost events during the following days. Blueberry varieties in advance stages of development may have some slight damage. Keep checking the weather forecast at your nearest Enviroweather station and take the necessary measures to prevent spring frost damage.

One word of caution: If you are planning to use your irrigation system for frost protection, check your system before turning it on and make sure you have abundant water to maintain the frost protection until temperatures rises above the freezing point. If you do not have enough water, do not turn on your irrigation for frost protection. You may cause more damage if you run out of water in the middle of a frost. The following is a contingency plan of action in case you want to use your irrigation system for frost protection.

Contingency plan for frost protection:

  • Reinstall suction lines and check primers on the pumps.
  • Test and service the pumping unit.
  • Replace filters and have spare filters available.
  • Check lines and sprinklers in the field for leaks and clogged nozzles and proper rotation.
  • Check water pressure on ends of distant lines.
  • Make sure drainage in and around fields is adequate. Make sure roadways around and through the field will withstand traffic at night during irrigation (the soil will be wet).
  • Have a high-intensity spotlight ready to plug into the truck to check sprinkler operation.
  • Have rain suits and boots available for everyone responsible for checking the irrigation system.
  • Have wires or drill bits available to unclog nozzles.
  • Have tools and replacement parts that are necessary to exchange nozzles and/or sprinklers.
  • Put shielded minimum thermometers in cold, average and warm areas of fields.
  • Hang some ribbons on trees or poles around fields to detect slight breezes.

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