Although the winter cold has yet to reach Florida, we still need to think about how best to protect plants for the next couple of months. UF’s Florida Automated Weather Network (FAWN) has a number of tools to help you make decisions as the temperature drops. Access data from weather stations close to you and get a number of forecasts based on local conditions by visiting http://fawn.ifas.ufl.edu/focus/topic.php/cold_protection.
The first step is to set a critical minimum temperature based on the crop you are growing. On the FAWN website there are helpful publications for ornamental crops in general as well as for some specific ones. You will also need to determine which FAWN site is closest to you. This may be a UF Research Station or one of the former Fruit Frost Stations. The NWS Forecast – Interactive Map tool is a good place to start for this.
Clicking on one of the stations shown on the interactive map will bring up graphs with the National Weather Service 4-day forecast for temperature, winds, and rain. You can see how well the NWS forecasts compare to actual data collected by using the Forecast Tracker tool.
During cold weather, the dew point has a significant effect on the rate and amount of heat that can be lost to the atmosphere. By entering the air and dew point temperatures for your location, the Overnight Minimum Temperature tool will give you a more accurate low temperature forecast.
Evaporative cooling may result in plant damage when water is used for cold protection during dry windy conditions. Evaporative cooling should always be taken into consideration. It is possible that, on nights when temperatures are close to critical levels, introduction of water could produce more damage than would result if no action was taken! The Evaporative Cooling Potential tool provides a guideline to help evaluate the risk of using water on a given night. Additionally, the Wet-Bulb Based Irrigation Cutoff Temperature tool will calculate air and wet-bulb temperatures and wind speeds to give a safe cutoff temperature for irrigation.
NEW this year is the FAWN Freeze Alert System which will send registered users 4 text or email messages per cold event, each containing specific information, from a user-selected FAWN site. A one-time fee covers the entire season.