• Blanket weeds can spread very rapidly.rain image by hazel proudlove from Fotolia.com
  
  Blanket weed is a form of algae, also referred to as string algae. Given optimal growth conditions, the weed can rapidly colonize water bodies by breaking off its new branches, which then spread and take over other areas. The term "blanket weed" refers to a number of algae that have similar forms and growth features, including Oedogonium, Spirogyra and Cladophora. The best control for blanket weed is prevention, since the use of algaecides is likely to harm the other plants and fish in the pond. Therefore, it's best to use chemical control methods as a last resort.
  
  

Barley Straw

• The use of barley straw on blanket weed is among the most effective natural blanket-weed control methods; there is a significant reduction in weeds within a few weeks of application. In waters with heavier infestation, it can take up to a full season to get rid of the weeds completely. The best time to apply barley straw is during early spring. Barley straw is effective because as it decomposes, it releases an enzyme that retards the growth of blanket weed. It also creates an environment for the growth of infusoria, the microscopic organisms that feed on algae blooms and control the growth of blanket weed. Barley straw is simple to use; just scatter it on top of the blanket-weed growth.
  
  

UV Sterilizers

• UV sterilizers are a safe way prevent and destroy pond algae, since they disrupt the RNA and DNA cycles of the weeds. The sterilizers do not produce any residue that can harm the plants or fish in the water. There are a wide range of UV sterilizers on the market, including low-pressure and medium/high-pressure lamps. The selection of the best UV sterilizer depends on the size of the pond or water body and the extent of the infestation. Blanket weed and other algae in the water absorb UV energy in proportion to their density.
  
  

Algaecides

• In more severe cases of blanket-weed infestation, use chemical-control methods such as copper-based compounds like copper chelate communes and copper sulfate. Endothall is a chemical that is also effective for the control of blanket weeds. Use algaecides in specified quantities, exactly as directed, or they can hurt the other plants and fish in the water. A number of water algaecides have restriction periods if the water is for irrigation or livestock. Chemicals get rid of blanket weeds very quickly. If blanket weeds are very heavy, treat the water in sections rather than at one time.