Planning For A Freeze

Planning For A Freeze

By far, the most widely used method of cold protection in Florida is the application of water. When using water for cold protection, growers must operate their irrigation systems to keep their crops from being damaged, while at the same time minimizing water use.

The Florida Automated Weather Network (FAWN) is a statewide system of 35 automated weather-observing sites — located from Homestead to Jay (near Pensacola) — that collect data every 15 minutes. The data, along with several calculated products and weather-related tools, are delivered to the public via the Internet and can also be retrieved via a telephone voice message system. FAWN has taken real-time weather information and developed the Cold Protection Toolkit — a step-by-step decision-making guide for using water for cold protection.

Temperature Tools

Inherent in every crop is a temperature at which cold air will begin to cause damage. So, the first step in the cold protection process is to determine the critical temperature for a given crop. FAWN’s online guide, Determining Critical Freezing Temperatures For Plants In Florida, provides assistance with determining the critical temperature for various crops in the state.

Next, the Fruit Frost Station Forecast tool provides a big-picture overview of whether cold protection may be needed during the upcoming week by retrieving a seven-day forecast for 180 of the prior National Weather Service (NWS) Fruit Frost Forecast locations.

On a night when critical temperatures are possible, the Forecast Tracker displays the NWS forecasted temperature and the observed temperature at any FAWN site on a 48-hour graph; a critical temperature can also be displayed as well.

The Minimum Overnight Temperature tool further evaluates the likelihood of the forecasted temperature occurring using the Brunt equation to estimate the minimum overnight temperature at each FAWN site. The sunset air and dew point temperatures can also be manually submitted for an estimate at the user’s location.

There is always a risk of further cooling due to evaporation when using irrigation systems for cold protection. The Evaporative Cooling Potential tool categorizes the evaporative cooling potential at each FAWN site.

Finally, the Wet-Bulb Based Irrigation Cutoff Temperature tool — which utilizes the basic cold-protection recommendation to discontinue irrigation when the wet bulb temperature reaches the critical temperature of the crop being protected — calculates an air temperature at which the wet bulb and your critical temperature would be equal. Air temperature, dew point temperature, and wind speed can also be manually submitted to determine the cutoff temperature at any location.

Substantial Savings

It has been estimated that use of these tools can save two hours of irrigation per cold event. During a relatively warm winter, one to three nights may require cold protection for a total savings of two to six irrigation hours. A cold winter, however, may produce four to 10 nights requiring cold protection for a savings of eight to 20 hours. Depending on the number of nights that need protection, billions of gallons of water and millions of dollars can potentially be saved by using FAWN Cold Protection tools.

The FAWN Cold Protection Toolkit provides step-by-step guidance for using water for cold protection by first helping users find their critical temperature, determining generally which upcoming nights might require cold protection, then guidance during individual cold events for when to start and stop irrigation. To use the FAWN Cold Protection Toolkit, visit http://fawn.ifas.ufl.edu, select Tools, and then Cold Protection Toolkit.

FAWN thanks the University of Florida/Institute of Food and Agricultural Sciences for financial support and infrastructure; the Florida Department of Agriculture and Consumer Services, South Florida Water Management District, Southwest Florida Water Management District, and St. Johns River Water Management District for their ongoing financial support.

Leave a Reply

Featured Stories
Crop ProtectionNimitz Receives Section 24(c) Label In Florida
September 4, 2015
The nematicide can be used in several Florida counties on direct-seeded crops. Read More
TomatoesCalifornia’s 2015 Processing Tomato Crop Is Forecast To Hit Record High
September 4, 2015
Production is forecast 4% above the 2014 crop, in part due to low disease and pest pressure. Read More
Apples & PearsPractices To Prevent Honeycrisp Postharvest Disorders
September 4, 2015
Honeycrisp can be extremely challenging to grow, harvest, and store. In the latest Penn State University Extension bulletin, Tara Baugher, Read More
GrapesWashington Winegrape Harvest Earlier Than Ever
September 3, 2015
  This year’s juice and winegrape harvest in Washington is historic. Michelle Moyer, Washington State University assistant professor, Dept. of Read More
FruitsBeaudry, Watkins, And Davenport Named Fellows Of American Society for Horticultural Science
September 3, 2015
Randolph Beaudry of Michigan State University (MSU), Joan Davenport of Washington State University (WSU), and Christopher Watkins of Cornell University Read More
GrapesWildfires Raise Fears Of Grape Smoke Taint
September 3, 2015
 The current wildfires in Washington have left many growers wondering if smoke taint could impact the flavor of their winegrapes. Read More
FruitsOrganic Industry Unites To “Bust Myths” Throughout September
September 2, 2015
Organic Trade Association members join forces in social media blitz to address misconceptions about organic production. Read More
CitrusResearchers Use Wasps To Protect Citrus Trees From Greening
September 2, 2015
A recent story in the Los Angeles Times highlights some of the new research being conducted in the fight against Read More
Apples & PearsHard Cider Organization Offers Accredited Program
September 1, 2015
United States Association of Cider Makers (USACM) introduces Sicera, the first-ever hard Cider Certification Program. This accreditation program is designed Read More
Apples & PearsProducts To Help Prevent Preharvest Drop In Apple Orchards
September 1, 2015
In the latest Extension bulletin from Penn State University, James Schupp associate professor of pomology suggests several products to apply Read More
The Latest
Crop ProtectionNimitz Receives Section 24(c) Label In Florida
September 4, 2015
The nematicide can be used in several Florida counties on direct-seeded crops. Read More
TomatoesCalifornia’s 2015 Processing Tomato Crop Is Forecast To…
September 4, 2015
Production is forecast 4% above the 2014 crop, in part due to low disease and pest pressure. Read More
Apples & PearsPractices To Prevent Honeycrisp Postharvest Disorders
September 4, 2015
Honeycrisp can be extremely challenging to grow, harvest, and store. In the latest Penn State University Extension bulletin, Tara Baugher, Read More
GrapesWashington Winegrape Harvest Earlier Than Ever
September 3, 2015
  This year’s juice and winegrape harvest in Washington is historic. Michelle Moyer, Washington State University assistant professor, Dept. of Read More
FruitsBeaudry, Watkins, And Davenport Named Fellows Of Ameri…
September 3, 2015
Randolph Beaudry of Michigan State University (MSU), Joan Davenport of Washington State University (WSU), and Christopher Watkins of Cornell University Read More
GrapesWildfires Raise Fears Of Grape Smoke Taint
September 3, 2015
 The current wildfires in Washington have left many growers wondering if smoke taint could impact the flavor of their winegrapes. Read More
FruitsOrganic Industry Unites To “Bust Myths” Thr…
September 2, 2015
Organic Trade Association members join forces in social media blitz to address misconceptions about organic production. Read More
CitrusResearchers Use Wasps To Protect Citrus Trees From Gree…
September 2, 2015
A recent story in the Los Angeles Times highlights some of the new research being conducted in the fight against Read More
Apples & PearsHard Cider Organization Offers Accredited Program
September 1, 2015
United States Association of Cider Makers (USACM) introduces Sicera, the first-ever hard Cider Certification Program. This accreditation program is designed Read More
Apples & PearsProducts To Help Prevent Preharvest Drop In Apple Orcha…
September 1, 2015
In the latest Extension bulletin from Penn State University, James Schupp associate professor of pomology suggests several products to apply Read More
Apples & PearsMarvin Sundquist Dies At 89
September 1, 2015
Marvin Sundquist, the retired owner of Sundquist Fruit and Cold Storage, died on Aug. 29 at the age of 89, Read More
Apples & PearsSyngenta Receives EPA Registration For Solatenol  Fungi…
September 1, 2015
The fungicide is available in four product offerings, pending state registrations. Read More
Grower Achievement AwardPero Family Farms Is The 2015 Grower Achievement Award …
September 1, 2015
The farm family that runs this Delray Beach-FL based operation develops, produces, packages, and markets its fresh-cut products while continuing to think outside the box. Read More
Dennis P. Broadaway
CitrusFlorida Citrus Packers Bestows Association’s Highest Ho…
September 1, 2015
For his dedication to the Sunshine State’s fresh citrus sector, Dennis Broadaway receives John T. Lesley Award for Excellence. Read More
Citrus Achievement AwardSaving Citrus A Perpetual Task
September 1, 2015
Orie Lee, the 2015 Citrus Achievement Award winner, talks about how growing citrus has changed in his lifetime and how it hasn't. Read More
Florida Ag Expo10th Annual Florida Ag Expo Field Tours To Tackle Produ…
September 1, 2015
There will be plenty to see and learn during the milestone event's exclusive field trials. Read More
Apples & PearsPennsylvania Congressman Supports CIDER Act
August 31, 2015
Freshman Congressman Ryan Costello (PA-06) spent a recent afternoon at Frecon Farms in Boyertown, PA, to tout the CIDER Act, Read More
Oriental Fruit fly
CitrusExotic Fruit Flies Invade South Florida
August 31, 2015
Efforts are under way to eradicate pest that attacks more than 230 different fruits, vegetables, and nuts. Read More