Barley straw has been a traditional treatment against blanketweed for hundreds of years. Our bestselling barley straw bale twin-packs come with a FREE additional bale. Barley Straw is a 100% natural product which, when added to your pond, will help to produce crystal clear water. Once the straw bales are wet, a natural process starts which combats algae growth. PondXpert Barley Straw is infused with natural lavender which helps produce significantly better results than standard barley straw. It also makes it smell better when sitting in the pond.