How to Clean Weeds Out of an Overpopulated Pond


A buildup of weeds and algae can have a negative effect on your garden pond. An excess of plant material may even be toxic to other plants and fish. Once your pond becomes overpopulated, it is essential to clean it out for the safety of the other life. There are a few ways to clean a garden pond. You can use chemicals or block sunlight from reaching the water, depending on whether you want to accomplish the task quickly or be environmentally friendly.

Step 1

Get a tarp large enough to cover the pond and pread it out over the water. It will block the sunlight that pond plants desperately need, helping to kill them.

Step 2

Take fish out of the pond. They may be harmed during chemical treatments. Put them in a holding tank with some of the pond water. Do not use fresh water because you will shock the fish.

Step 3

Pour a weedkiller in the pond. Choose one formulated to be effective in water such as an herbicide, aquacide or algaecide. Follow the directions on the container to determine the dosage.

Step 4

Add bacteria to the pond to help break down weeds. Use the size of the pond to determine how much to pour in.

Step 5

Set up a filter to rid the water of algae. You need a power source nearby, as filters run on electricity. If you need to use an extension cord, make sure it is an outdoor one. Run the filter continuously.

Step 6

Let the solutions and tarp work for about one week. This is how long it takes for the chemicals to weaken the plants.

Step 7

Take the tarp off the top of the water. Run the rake through the water to remove the weeds. Some will be floating on top and others will be at the bottom of the pond. Make sure you remove all the dead plant material.

Step 8

Add grass carp to the pond once the water has had time to return to normal. (If there are chemicals present, the carp will get sick.) The fish are hardy eaters and will multiply, consuming all the weeds. All you need are a few for results.

Things You'll Need

  • Holding tank
  • Pond water
  • Tarp
  • Herbicide, aquacide or algaecide
  • Rake
  • Bacteria
  • Electric water filter
  • Grass carp (optional)


  • Washington State University: Maintaining Your Garden Pond
  • Pond Solutions: Garden Pond, Water Garden, Fish Pond and Water Management Chemicals
Keywords: clean weeds, weeds in pond, clean pond

About this Author

Kelly Shetsky has been a broadcast journalist for more than 10 years, researching, writing, producing and reporting daily on many topics. In addition, she writes for several websites, specializing in medical, health and fitness, arts and entertainment, travel and business. Shetsky has a Bachelor of Arts in communications from Marist College.