Pond Fertilization

A properly executed fertilization program is one of the most beneficial pond management tools available
to pond and lake owners and managers.  A proper fertilization program can triple or quadruple the
productivity of a pond.  This means that your pond can support three to four times more fish than an
unfertilized pond!  When you fertilize, your goal is to produce a phytoplankton bloom.  This can be seen in
the photo below.  The plankton bloom will give the water a green color.  This is the base of the food chain
in your pond.  The more phytoplankton there is, the more zooplankton and insects there will be feeding
on it.  Young fish feed on the zooplankton and larger fish feed on the smaller fish.  So by improving the
base of the food chain, you also improve the food available to the rest of the fish.    

The process of fertilizing begins with having a water sample from your pond checked for alkalinity to
determine if an application of agricultural lime is necessary.  If it is, the ag lime should be applied ideally
in the fall or winter.  This allows the pond to be ready to fertilize in the spring.   However, lime can be
applied in the spring and summer as well.  Before applying the lime, the amount of water flow running
through the pond should be considered.  Ponds with high flow rates will likely require more frequent
applications of both lime (if needed), and fertilizer.  In this case, fertilization and liming may not be
practical.  Finally, the presence of aquatic vegetation should be evaluated.  
A fertilization program
should not begin when unwanted aquatic vegetation is present.  Fertilizing the pond will feed the
vegetation and cause the vegetation to grow more.

Begin fertilizing the pond in the spring when the water temperature rises above 60 degrees F (March in
the southeast).  Apply the fertilizer according to the specific fertilizer's directions.  Every pond is different,
but generally, you should apply the fertilizer about once per month depending on the water visibility.  You
should maintain the water visibility between 18 and 24 inches.  The visibility can be measured using an
8-inch white disk.  Lower the disk into the water until it disappears.  Then raise it until it reappears.  At this
point, measure the distance from the water surface to the disk.  This is the visibility.  If the water is too
clear (visibility greater than 24 inches), it is time to fertilize.  If the green plankton bloom is too thick
(visibility less than 18 inches), you should stop fertilizing until the visibility becomes greater then 24
inches.  You should stop fertilizing around November when the water temperature drops below 60
degrees F.  

Feel free to contact us if you have any questions about fertilizing your pond, lime application, or pond
management in general.     

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C&M Pond Liming