If you have a pond that is experiencing a problem with algae growth, you can use barley straw to control the algae. There are a couple things to keep in mind if you decide to do this.

1 - Make sure you use dried barley straw. If you use barley hay, or barley stray that is not completely dried, it will release nitrogen and phosphorus and it will make your algae problem worse!

2 - The amount of straw to apply depends on the surface area of the pond, not the volume. Apply 1 pound of straw for every 400 square feet of pond surface.

3 - Don't just throw the straw in the pond. Put the straw into a water-permeable bag and weight it down so that it remains under water. For large ponds, break the straw up into multiple bags with about 10 pounds of straw in each bag. Since algae is usually produce in shallow water, make sure to sink these bags in the shallow area where algae is produced.

4 - Barley straw controls the production of algea, but it does nothing to control algae that has already been produced. Therefore, you need to get the straw in the water before the algae begins to grow. As the straw will last for 4 -5 months, the best usage is to get it into the water 1 month before the algae usually begins to grow. In my part of the country, this means April. Adjust as needed based on where you live.