Although it may not be the first thing that comes to mind when you think about compost, slimy green pond algae is an ideal compost ingredient. Adding pond algae to your compost pile provides nitrogen, an essential nutrient for the millions of decomposing bacteria at work on your compost. According to the University of Illinois Cooperative Extension, these aerobic bacteria use the nitrogen in compost ingredients such as pond algae to grow and reproduce. A key factor in composting pond algae successfully is ensuring that you layer your compost correctly.
Scoop the algae from your pond with a leaf rake or a pool-skimming pool. Pull the small clumps of algae together in the water and scoop the collection up with your rake, letting most of the water drain out before putting the algae in a bucket for transport.
Mix the algae thoroughly with other nitrogen-rich organic materials. Common high-nitrogen compost ingredients include fresh grass clippings, horse or cow manure, coffee grounds and vegetable scraps.
Gather a variety of carbon-rich materials such as straw, dead leaves, dried grass clippings and old hay.
Spread a layer of the carbon-rich organic materials 4 to 6 inches deep on the ground in a 3-square-foot area.
Place a 3-inch layer of high-nitrogen materials, including the pond algae, over the carbon layer. Sprinkle several handfuls of plain topsoil over the pile to introduce additional decomposing bacteria and help speed the composting process.
Spray the pile gently with your garden hose.
Build your compost pile with alternating layers of carbon and nitrogen materials until it is 3 to 4 feet tall. Use a manure fork to push the center of your pile down slightly to help channel rain water into your compost to keep it moist.
Check the moisture level of your pond algae compost every two or three days. Ideally, it should be about as damp as a wrung-out sponge. Squeeze a handful of the composting material to check; your pile is at the correct moisture level if you are able to wring out one or two drops of liquid, according to the University of Illinois Cooperative Extension.
Wait for four to five weeks for your pond algae compost pile to heat up, then mix the layers with a manure fork. Continue aerating the compost by turning the layers once every seven to 10 days.