Barley + Lavender: A Natural Algae Inhibitor

Barley & Lavender Algae Inhibitor

What is it?

Research conducted at the Centre for Aquatic Plant Management in the United Kingdom has demonstrated that a combination of barley straw and lavender stalks can inhibit the growth of algae in ponds in a completely organic and environmentally safe manner.

The barley straw/lavender stalk combination will control algae in bodies of water ranging from small garden ponds to large reservoirs without harming plants or fish. It does not kill algae already present. Instead it prevents the growth of new algae cells so that the algae problem is controlled. If applied in the same manner described below it will assist in keeping ponds clear.

How does it work?

When the barley straw/lavender stalk combination lies near the surface of a body of water, it starts to decay. During this process a natural chemical is released that inhibits the growth of algae. This decay is a microbial process and is temperature dependent. Being more active in summer than in winter. As a generalization the process will remain active for six months after which activity gradually decreases.

When should it be applied?

Initially in spring before major algae growth begins and again in the fall before the water gets too cold. In our Pacific Northwest climate that generally means April/May and October. Twice yearly renewal is necessary to keep ponds clear.

How much should be applied?

Two factors are key – the surface area of the pond and the amount of water movement present. Volume is not as important for the simple reason that most of the algae growth occurs in the upper (warmer) few inches of the pond. The greater the degree of water flow or movement – the greater rate of oxygenation and hence microbial decay of the lavender/barley straw and stalks. For ponds with severe algae problems, it is generally better to provide more treatment initially and then reduce the quantity gradually.

Where should it be applied?

The barley needs to be well oxygenated in order for its decomposition to be active and the natural chemical it releases to be effective. The package should be placed at a point where water can swirl over it. This will help spread the released chemicals throughout the pond. The best place for the Barley is in the Biofalls beneath the lava rock or Bioballs.

How soon will the effects be noticed?

It depends on the temperature of the water and the degree of algae growth prior to the application. Algae inhibition is faster in warm water than in cold, but then so is algae growth. As a broad statement, moderately affected ponds during warmer months could take 6-8 weeks for results to be noticeable. Keep in mind that this is more of a long term treatment for preventative use and not a quick fix for existing algae. It should be used in combination with our recommended weekly maintenance products - Algaecide, Beneficial Bacteria, and SAB Stream & Pond Cleaner.


Our x-small Lavender Algae Inhibitor™ will be effective in bodies of water up to 200 sq. ft. surface area.

Our small Lavender Algae Inhibitor™ will be effective in bodies of water up to 400 sq. ft. surface area

Our large Lavender Algae Inhibitor™ will be effective in bodies of water up to 800 sq ft surface area

Our x-large Lavender Algae Inhibitor™ will be effective in bodies of water up to 1600 sq ft surface area