Virtually all blueberry fields in Florida are subject to late winter or early spring freezes, which can cause serious reductions in yield. This is a list of activities for freeze preparation. The list was originally published by Mike Mainland in the North Carolina Blueberry News, Vol. 7, No. 1 and has been modified by IFAS faculty and FBGA board members.

1. Flush all overhead sprinklers to clear debris – remove heads and flush.
2. Test and service the pumping units, replace filters, and have spare filters available.
3. Treat diesel tanks for water and algae.
4. Check lines and sprinklers in the field for leaks and clogged nozzles.
5. Check water pressure on ends of distant lines.
6. Make sure drainage in and around fields is adequate. Make sure roadways around and through the fields will withstand traffic at night during irrigation.
7. Remove or relocate any equipment that may impede or pose a danger to vehicular traffic.
8. Have a (remote-controlled, magnetic roof-mounted) high-intensity spotlight ready to plug into the truck to check sprinklers.
9. Put shielded minimum thermometers in cold, average, and warm areas of fields – at the average height of the middle of the bushes.
10. Consider purchasing weather stations that communicate real-time weather conditions to computers and smartphones.
11. Hang some ribbons on trees or poles around fields to detect slight breezes.
12. Identify a good source of agricultural weather information and watch it closely. Consider subscribing to a weather service that issues freeze warnings.
13. Consider purchasing a monitor that calls you when the temperature gets low.
14. Consider purchasing a handheld wind meter or anemometer to measure wind speed.
15. Consider purchasing a sling psychrometer to measure wet bulb and dry bulb temperatures, relative humidity, and dew point.
16. Have rain suits and boots available for everyone responsible for checking the irrigation system.
17. Have wires available to unclog nozzles.
18. Have tools and replacement parts necessary to exchange nozzles and/or sprinklers.
19. Be certain you know the “safe cutoff temperature” before you shut down your overhead freeze protection irrigation. This temperature can be as high as 40 degrees F if the dew point is low and wind is high.
20. Fill all vehicles with fuel before the freeze event.
21. Make sure irrigation system fuel tanks are full.
22. After inspecting, cleaning, and making any repairs, operate the overhead irrigation system to make sure it is working properly. Then drain the system and close or seal the drain plugs.
23. Have help available or on call if needed for emergencies.

Additional resources –

Weathering the Winter. The Blueberry News. Vol 10 (2) January 2021. Pp 20-21, 38 https://bit.ly/3vhI10j

Protecting blueberries from freezes in Florida. https://edis.ifas.ufl.edu/pdf/HS/HS21600.pdf

Cold Protection toolkit. Florida Automated Weather Network (FAWN), Univ. of Florida Extension. https://fawn.ifas.ufl.edu/tools/coldp/

AgroClimate website. http://agroclimate.org/

University of Georgia Extension Circular 1128, Preparing Your Blueberry Freeze Protection System. https://secure.caes.uga.edu/extension/publications/files/pdf/C%201128_2.PDF