Pond fertilization is an excellent tool in pond management. It allows you to improve the water quality greatly. You can even increase fish production in your pond by as much as 300%, because of the increased phytoplankton that results from pond fertilization. Organisms feed on phytoplankton and they flourish in darker waters which result from the fertilization. There is also less algae and fewer submersed aquatic weeds following fertilization. Therefore you should take the time to learn about the details of pond fertilization.

Know Which Types of Ponds To Fertilize

It is incredibly important to only fertilize ponds that are good candidates for pond fertilization because it is not beneficial for every pond. If the water is not hard enough or the soil pH is low, the pond should not be fertilized. You can adjust the pH of the water by applying lime but must wait 4-6 weeks following application before you can attempt pond fertilization.  

If a pond has aquatic weed growth, avoid fertilization. Such growth must be controlled prior to pond fertilization. Black water ponds or muddy ponds are also not good candidates for pond fertilization. If the pond gets runoff from animal manure or organic fertilizer, it does not need pond fertilization.  

Choosing The Right Fertilizer

When you are selecting fertilizer for your pond, be sure to get one that is highly water soluble. If it sinks to the bottom of the pond, you will find that it binds to the soil there and will not fertilize the water. Highly soluble pond fertilizers come in powder, granular and liquid forms. Be sure that the fertilizer has phosphorus, very little nitrogen and no potassium.  

Getting Started With Pond Fertilization

You should do your initial pond fertilization when the water temperature is around 60°F. This is typically around March or April, depending on where you live. You may only need 1 treatment per year, however 3 times a year is the average. Give the pond 2 weeks to adjust following the initial application before deciding if you need further applications. To help you decide when your pond no longer needs additional fertilization, the guideline is to stop when you can no longer see an object that is 18” below the water surface.   

If you are using liquid fertilizer you will need to mix it with 10 parts water to 1 part fertilizer before distributing it before across the pond. Powder or granular fertilizers should be dissolved in water and the same ratio used prior to application.  

Make sure you do not fertilize your pond if the temperature of the water is lower than 60°F. Typically this is in September or October. Pond fertilization when water is too cold is ineffective and may cause algae issues that become apparent when the water warms up again.  

Be sure to purchase a quality pond fertilization product and seek professional help if you have questions about the process. Pond fertilization is an important aspect of caring for and maintaining a healthy pond.


W. P. Law, Inc. is one of the Southeast's leading suppliers of fluid handling equipment for farmers, contractors, and industries. Founded in 1970 in Lexington, South Carolina, the company has seven locations throughout the state.  W.P. Law, Inc.’s reputation is built upon the experience and expertise to find economical solutions to customer's needs.