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How to Grow Blue & Green Algae

By Larry Parr ; Updated September 21, 2017
Blue and green algae often form a scum over shallow, warm pools of water and can be deadly to animals.

Blue and green algae are bacteria (cyanobacteria) that act very much like a plant. Blue and green algae need sunlight, warmth and the proper nutrients to grow and thrive. While many people today are experimenting with blue and green algae as an energy source, such algae also can produce toxins that, in quantity, are lethal to large animals.

Create a shallow, still pond of water warmed by the sun to 65 to 80 degrees Fahrenheit. This will produce the best algae growth.

Remove trees or other vegetation, which block sunlight from reaching the pond. Keep the water warm by sunlight, which is a key element for raising blue and green algae.

Add 1 lb. of raw or composted manure per 1,000 cubic feet of water to stimulate algae growth. Spread the manure over the top of the water and allow it to settle to the bottom.

Harvest the algae using a rake. Add an additional 1/2 lb. of manure that is high in nitrogen and phosphorous per 1,000 cubic feet of water to maintain algae growth over a prolonged period.


Things You Will Need

  • Pond of warm water
  • Phosphorous
  • Nitrogen
  • Rake


  • Do not allow animals to drink water from a blue or green algae pool, as such water can be poisonous.

About the Author


Larry Parr has been a full-time professional freelance writer for more than 30 years. For 25 years he wrote cartoons for television, everything from "Smurfs" to "Spider-Man." Today Parr train dogs and write articles on a variety of topics for websites worldwide.