Homemade Algaecide

Jonae Fredericks

Common to many habitats, algae range in size from very small, single-celled organisms to large ocean kelp measuring 52 feet. The green masses of floating slime grow wherever water and sunlight meet and provide food for various forms of aquatic wildlife.

Some algae is beneficial, but too much of a good thing can be bad -- especially in your home pond. Overgrown algae discolor pond water and cause it to yield unpleasant odors. Before you reach for chemical algaecides that may expose aquatic life to harm, look to your pantry for a homemade alternative.


Choose an organic cornmeal, free of pesticides or other harmful chemicals. Thicker socks will work if nylon is unavailable, but it may take longer for the cornmeal to leach into the pond.


Make sure your pond fish stay well-fed with the proper allocation of fish food. Hungry fish may eat the cornmeal and spoil your algae removal plans.

  1. Cut a foot off a pair of pantyhose or use a thin, nylon stocking. Nylon works best because the fabric is generally thinner than a cotton sock.

  2. Fill the pantyhose or sock with 1 cup of finely ground cornmeal. Use 1 cup of cornmeal for every 100 square feet of pond. Use more than one stocking if your pond is large.

  3. Tie-off the top of the pantyhose. Knot it tightly so the cornmeal can't spill out. Use an elastic rubber band to secure the knot and keep it from slipping.

  4. Set the pantyhose full of finely ground cornmeal into the pond. The pantyhose may bob along the top of the water or sink. Either way is fine, as long as the cornmeal contacts the water.

  5. Remove the stocking from the pond when all of the cornmeal has leached away into the water. Repeat the process if your algae problems return.