Picture of Barley Straw.

Water Gardens & Features Q & A

Q: How does barley straw work to control algae? – Emma of Michigan

A: Barley straw is no magic bullet to rid your decorative pond of algae. But when used as a preventive measure, barley straw offers pond owners an attractive option to chemical products to manage those dreaded green blooms.

The Science Behind Barley: Barley straw has been widely used for decades to control algae blooms in many bodies of water, including large reservoirs and canals. Researchers have yet to precisely pinpoint how it works, but generally, it’s believed that the straw may alter the nutrient balance in the water, starving the algae to death, or the straw’s decomposition may be produce compounds toxic to algae.

Experts usually consider barley straw to be algistatic, or an algae preventive, rather than an algaecide, or an algae killer. It has not been found to harm fish, water fowl or pond inhabitants in any way and, in fact, some studies suggest the straw benefits fish health.

Using It In Your Pond: Science aside, what’s important to pond keepers is how to use it in their ponds. Currently, hobbyists can choose from three different types of barley products: barley straw in bale form, barley pellets and barley extract. When used correctly, each will work to suppress algae blooms in the pond.

Barley Straw Bales: Typically available loose in a mesh bag, bales of barley straw should be placed in the pond several months before bloom conditions are expected to occur (around March or April, depending on your climate) as the straw must start to decompose before it releases it’s algae-suppressing substances. One pound of barley straw will treat a 1,000-gallon pond for approximately three months. Be sure to keep the straw well-aerated, floating it near your water fall or stream or in shallow water, if possible. Besides the length of time it takes for bales to decompose another downside is that they can be counter productive if left in the pond for too long. They can eventually become a nutrient source for algae as well.

Barley Pellets: Compressed into a compact form, the barley pellets also contain all the beneficial algae-suppressing substances found in barley straw without the unsightly look of bales, pillows or pads. They’re designed to break down quickly, and produce phosphate-combating humic substances that suppress algae growth. The pellets may also buffer pH and control alkalinity in your pond. A 4.4-pound bag will treat a 150-gallon pond for up to one year or a 500-gallon pond for up to seven months; a 10.5-pound bag will treat a 1,000-gallon pond for up to nine months or a 2,500-gallon pond for up to four months.

Barley Extract PLUS: Offering the benefits of barley straw without the mess or unsightly bale floating in your pond, barley extract contains the algae-suppressing substances in liquid form. Because you don’t have to wait for the barley straw to decompose, it starts to work on contact. Another great benefit of Barley Extract PLUS is that it is enchanced with sludge-eating natural bacteria to also help reduce muck building on rocks, gravel and/or liner. An 8-ounce container treats up to 800 gallons for three months; a 16-ounce bottle treats up to 1,500 gallons for three months.

POND TALK: Have you found barley straw to effectively control algae in your decorative pond?

Algae Growing in a Water Garden During Winter.

Q: I shut my water garden down for the winter, but I still see some algae growth. Can algae grow in cooler temperatures?

A: In some cases, a pond that stays clean and clear through the summer can blow up into an algal nightmare in the fall. Shutting down your watergarden ceases the flow-through characteristics of the pond. This reduces the amount of filtration that occurs both mechanically (i.e. skimmers) and biologically (i.e. filterfalls). Since there is less flow, it is a good idea to bump up the amount of bacteria in the pond by adding Seasonal Defense Bacteria with Barley. These bacteria operate in cooler conditions and will greatly reduce the amount of nutrients in the water, and also contains barley straw to naturally help with the algae. Using Oxy-Lift Defense to scrub down your rocks will also help to remove any debris build up.

Barley Straw & Barley Straw Extract

Q: I have heard that barley straw will control algae. Is this true? Also I have noticed a product on the market called barley straw extract. Why can’t I just use a bale of barley straw? – Samantha of California

A: Barley Straw has been known for a long time to help in the control of algae. The concept is that as the straw decays, a chemical is released that will reduce algae growth. The problem with using actual Barley Straw is that it takes up to 8 weeks for the straw to decay and begin to work. It also “decays”, which means it puts nutrients back into the pond that will cause future algae growth.

We strongly recommend using an extract (liquid) such as Barley Straw Extract PLUS. The extract is the by product of rotting barley straw. This starts to work on contact instead of having to wait weeks for the straw to decay. It also will not contribute to the nutrient load and is all-natural and safe.

Another great benefit of using the Barley Straw Extract PLUS product is that it contains muck & sludge reducing bacteria.