The average farm pond can quickly become infested with unwanted vegetation or weeds. A weedy pond can be reclaimed with timely management considerations. Fall and spring are the best times to apply herbicides to control unwanted weed and algae populations. Herbicides should be applied after the water temperature reaches 60 degrees F.
The landowner must first decide what their objective is for their pond. Do you want to establish a “fishery” in the pond? Do you just want a nice clean attractive body of water for aesthetic beauty? Do you just want to water livestock from the pond? Depending on your goals for your pond, your approach will be different.
If your pond is already overcome with weeds, we can make a recommendation to help you gain control of the unwanted vegetation. The recommendation will be different for ponds with a fish population to protect the fish.
Good pond weed control will require some preventative measures. Grass carp are part of a fundamental vegetation control plan. Stocking 5 to 15 grass carp per acre is an important tool but not the total solution. Next, you need to prevent sunlight from reaching the pond bottom. This will prevent many weeds from growing in the pond. This can be accomplished by either fertilizing the pond water or coloring the water with a dye. Barley straw at the rate of 4 to 6 bales per acre will act as a natural herbicide and provide some weed control in the pond. If all else fails, there are several really good herbicides available for targeting pond weed problems.
Before you apply a pond herbicide, you should positively identify the pond weed. This will allow the correct herbicide to be applied. You should also calibrate your sprayer to make sure you apply the correct rate. Don’t forget to use an aquatic surfactant to improve the efficacy of the herbicide. Finally, never use anything except for an aquatic herbicide in your pond.
Now, if your goal is to manage your pond to maintain a “fishery” in the pond, there are some additional considerations. Some of these would be dissolved oxygen in the water, alkalinity, nutrient load, fish population.
Your goal will be to maintain a healthy number of fish in the pond to avoid a fish kill. Once a pond has a balanced population of bluegill and bass, you will need to routinely remove fish from the pond. Remember, there’s only so much oxygen and elbow room in your pond.
For more information on pond management, call your local Extension office.