While Florida is not known for cold weather, it does get cold enough on occasion that growers need to watch for the salt-out of liquid fertilizers. While liquid fertilizers have a host of benefits over dry fertilizers, the salt-out of liquid fertilizers at cold temperatures is one of the few disadvantages.
Liquid fertilizers salt-out when the fertilizer solids come out of solution and form crystals or sediment in the bottom of the tank during cold weather and options for dealing with it were shared in a recent UF/IFAS Tip of the Week, by multi-county citrus Extension agent Ajia Paolillo. Salting-out is more likely to occur in higher analysis liquid-fertilizer solutions; products that are 32 percent nitrogen solution salt out around 31 to 32 degrees Fahrenheit, while products that are 30 percent salt out around 15 degrees.
Once a liquid fertilizer has developed solids it is difficult to mix back into solution, the fertilizer will not be as effective, and it can damage the lining of your tank and clog irrigation lines.
Stopping the Salt-Out of Liquid Fertilizers
If you’re concerned about your liquid fertilizers salting out, contact us at Griffin Fertilizer for solutions. For instance, we can adjust the solubility rates of your fertilizer based on temperature because different materials have different solubility rates at different temperatures. Combining different nutrients or creating different ratios—such as decreasing the percentage of nitrogen in the tank—will change the solubility rates of a fertilizer mixture and will keep it from salting out.
It’s also a good idea to use up higher analysis liquid fertilizers during warm weather and switching to a fertilizer that’s more suited to cold weather if salting out is a concern. Similarly, having a full fertilizer tank decreases the likelihood of a liquid fertilizer salting out, as does having a holding tank that is painted a dark color to absorb more of the sun’s heat.
Once a liquid fertilizer has salted out, you don’t want to disturb it in the tank because it could tear a tank liner or clog up irrigation lines if you attempt to use it. Usually, it’s best to wait for the weather to warm up consistently, which will cause the salt to dissolve.
Paolillo recommended the following when the weather is cold concerning the salt-out of liquid fertilizers:
Before running the fertilizer through the irrigation system, check the holding tank for signs of crystallization and sediment.
Agitate the liquid in the tank to attempt to dissolve the solids back into solution.
If the solids will not dissolve back into solution, wait until the weather is warmer and attempt agitation again.
Griffin Fertilizer has been in the fertilizer business since 1959; contact us if the salt-out of your liquid fertilizer is an issue.