How to Use Duckweed

Duckweed floating on a freshwater pond image by Klein Kroos


Duckweed, botanically known as lemna, is a tiny pale green aquatic plant that floats atop fresh water lakes, ponds and pools. Duckweed throws seeds and has between one and three petals on each plant that grow up to an 1/8 inch in length each. Every petal grouping has a thin root string that hangs down into the water. Ducks love to eat Duckweed and can spread it as they move amongst bodies of water.

Step 1

Acquire healthy Duckweed plants from a reputable aqua garden supplier either online or at a local bricks and mortar storefront. They come in plastic bags or plastic cups with hundreds or thousands of individual plants per package. Because it is a fast colonizer, just a couple packages can establish themselves in a medium size pond in a few months.

Step 2

Tip the bag or container gently onto the surface of the water, allowing the Duckweed to flow out and begin to float on the surface. Most plants will right themselves orienting their root side down. Use your fingers to flip over the few plants that do not right themselves.

Step 3

Allow the Duckweed to float on the surface of the water where it will naturally form into colonies. No fertilizer is required as it lives on the nutrients in the water supply. Duckweed thrives in full and partial sun.

Step 4

Keep the Duckweed population in check to prevent de-oxygenation and threats to the body of water's ecosystem and to fish and other aquatic animals. Skim portions of the surface periodically to lift the duckweed out and discard it.

Tips and Warnings

  • Duckweed thrives on calm waters where it grows dense colonies that can completely coat the surface of the water. But this can cut off sunlight penetration and oxygen, which will killing fish and other water life. Introduce and manage its spread carefully.

Things You'll Need

  • Duckweed plants
  • Freshwater body of water
  • Net pond or pool skimmer


  • Common Duckweed
  • USDA Plants Database profile on Duckweed
Keywords: duckweed, aquaculture, water, plants, lemna, floating

About this Author

An omni-curious communications professional, Dena Kane has more than 17 years of experience writing and editing content for online publications, corporate communications, business clients, industry journals, as well as film and broadcast media. Kane studied political science at the University of California, San Diego.

Photo by: Klein Kroos

Article provided by eHow Home & Garden | How to Use Duckweed