Managing Fertility In Ponds And Lakes
Wednesday, August 6th, 2008Managing fertility in ponds and lakes.
The idea of fertilizing a pond seems strange to many people, but is something that may need to be done.
The reasons for adding fertilizer are pretty simple. Fish eat many types of aquatic invertebrates. These are bugs that exist in pond settings. The bugs need something to eat to get fat for the fish, and that something is algae.
Algae Bloom
The algae that serves this purpose best, is phytoplankton. This is a simple, single cell organism that grows in suspension in the water of ponds and lakes. The nice blue green tint in the water is what you are after. In fact, you want it to be dark enough that you can not see an 8 inch black and white disk at a depth 18 to 24 inches. Algae bloom has the added benefit of reducing weed populations because of the reduction in light penetration.
Fertilizer
The fertilizer you need to use, should be high in phosphorous, and low in the other two main ingredients.
When you look at the analysis of a bag of common fertilizer, you will see 3 numbers, divided by a dash. The middle number is the one you are after. There are several good products on the market for pond and lake fertilizing. and several methods of application. If a powder is used, it can be spread as evenly as possible on the surface of the water, or with an aquatic applicator which will allow it to dissolve gradually. If a liquid is used, it should be mixed with water before application, or it will sink to the bottom and be neutralized. After you have fertilized once, you should check the pond periodically for visual depth. You will need to fertilize regularly at 2 week intervals through the summer, checking the light penetration as you do. Light should not penetrate deeper than 24 inches, and should not penetrate less than 12 to 18 inches. If visibility is less than a foot, suspend fertilizing until it clears to 18 to 24 inches. Fertilizing should begin as soon as the water temperature reaches 60 degrees. I will include more information on how to construct a sechi disk, the type and amount of fertilizer, and the intervals between applications, as time permits.
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