We are pleased to offer barley straw (approximately 25-30 lbs per bale) for algae issues in your pond! And now in 550g bags for your smaller backyard koi and goldfish ponds!
How much barley straw do I need?
For smaller ponds measured in gallons, we recommend using one lb of barley straw per 1,000 gallons per loading dose.
For larger ponds, the amount of barley straw you will need depends on the actual surface acreage of the pond. Please refer to the chart below to determine how many bales you will need for your specific pond size.
Do you really need two doses per year in your pond?
This will depend 100% on your climate and on your pond. Warmer water increases algae growth potential and also increases the rate at which barley straw decomposes. The climate in Ontario lends itself to one to two doses per year but of course for our customers in other parts of Canada, it will be location and climate specific. On top of the specific location and climate factor, each pond will also be different and will react differently. If your pond has a history of really bad and/or long time established algae problems, one dose will most likely not be enough. After barley straw has been submerged in water for a few months, the enzyme emitting and decomposition effect begin to wear off, and it may need to be replaced. Each year can also be completely different from the year before. Two doses is the norm, but there have been years when mid-July rolled around and there was absolutely no sign of algae growth. We just left the first dose of barley straw in and let it continue to do its work and kept an eye on it to see if a second dose was required or not.
When is the best time to apply the barley straw?
Because barley straw is more of a preventative method of algae control, the earlier the better. In Ontario, we usually put barley straw in our pond in early April, before the algae normally begins to grow. Then in mid July we'll usually replace the straw and put in a second dose. But again - each location, each pond and each year can be completely different ...
Full details and scientific information is also available at:
Delivered to your door in heavy plastic bags for easy storage and to keep any mess to a bare minimum!
A Guide to Pond Barley Straw & How it Works for Clear Pond Water
A small amount of algae growth is normal in most bodies of water, and in low quantities it can actually be beneficial to ponds and fish! Algae may grow fast under the right conditions, but the majority of algae species are still plants, and plants provide oxygen, deplete excess nutrients, and provide water filtration. The problem with algae is when the weed is left to grow unchecked, it can lead to massive “blooms” which place a huge amount of stress on a ponds eco-system. As algae die and decompose, beneficial bacteria consume oxygen to break down the harmful substances they produce, which leads to lower oxygen for fish, and less efficient filtration as bacteria struggle to keep up with demands.
Although there are effective mechanical (and chemical) ways to quickly get rid of algae, there has been a push to explore more natural methods to reduce costs, maintenance, and to prevent potential damage to the pond in the long run. Barley straw is at the front of that push! Even though barley cannot remove algae as fast as other treatments, it works as a great long-term control method and can help stop algae coming back in future, which is why it’s becoming more and more popular in the fish keeping hobby.
How does barley extract work to kill algae?
To discover how barley works as an algae control method, we need to look into the details and take a look at each step of the decomposition process as it enters your pond:
1) Barley straw is placed in the pond and slowly begins to decompose. During decomposition the cellular structure of the barley begins to break down, and the rate of breakdown is dependent on water temperature and oxygen content. Beneficial bacteria will work faster in warmer temperatures and well-aerated conditions, so you’ll see faster results from barley in summer compared to winter. After a few weeks in the pond, decomposition changes from being bacteria dominant to fungi dominant, leading to “rotting”.
2) As fungi eat away at the remains of the barley material, humic acid is produced, which is the first major step towards algae control. As the humic acids leech into the surrounding water it reacts with oxygen and sunlight, becoming more and more unstable and eventually forming a super-oxide radical which leads to hydrogen peroxide.
3) Hydrogen peroxide is a powerful algaecide, and when produced from correctly dosed barley it’s in a low enough concentration to be safe for fish and still work as an algae deterrent. A concentration of just 2 parts per million (ppm) is sufficient for controlling the growth of algae in ponds, and as hydrogen peroxide is more stable in fresh water compared to salt water, it stays effective for longer and requires less frequent dosing.
Will barley get rid of my algae problem?
The effectiveness of barley straw will depend on the amount of algae you have, the type of algae, and how quickly you want it gone! As with many natural methods of control, the turnaround to see results is often much slower in comparison to mechanical and chemical treatments. If you have a major algae bloom in your pond, and your fish are suffering, opting for a mechanical treatment (i.e., UV Clarifier) to resolve the problem and then using barley as a preventive method is usually the best way forward.
In-fact, in most cases of algae growth, we would first recommend mechanical removal and a pond clean-up before adding barley to the system. Having large amounts of algae usually indicates excess nutrients, excess waste, or low-aerated conditions. Adding more organic material to the pond, such as barley, would only make the problem worse as it takes so long to become effective. As well as this, as barley straw is reliant on the beneficial bacteria in your pond to break it down, adding it to low oxygen and high waste systems will actually reduces its effectiveness, as bacteria are likely already struggling with the low oxygen content and large bio-load present.
Barley straw works best in high-oxygen, well-aerated, and algae-free ponds as it’s free to decompose quickly and more efficiently. For this reason, we always recommend barley as a preventive measure, and not to stop a huge algae bloom already in place. The best way to use barley would be to first eliminate any major algae blooms, and then supplement with straw to prevent blooms coming back the following season.
Are barley straw clarifiers safe for fish?
If dosed moderately, and assuming your ponds water quality is good and there are no current algae blooms, barley straw should be perfectly fine for fish and plants. Even though barley decomposes to eventually form hydrogen peroxide, which is highly toxic, it will be in such low concentrations that fish won’t experience any negative effects.
The main problems that can arise from using barley straw are drops in water quality, which are often caused by adding barley to a pond with low aeration, poor filtration, or high waste. Barley straw is carbon based and organic in nature; no different to leaves, twigs, and pollen which enters the pond and contributes to waste. Just like other organic material, during decomposition it will break down and produce harmful substances, such as ammonia, as a by-product. Beneficial bacteria would need to break this down or it can become a major issue for fish as concentrations rise. Adding barley straw to a pond which is already struggling with high waste problems would only amplify the issues, causing drops in oxygen and a rise in harmful substances.
If your water quality tests are coming back as good, and you have adequate filtration and aeration in place, adding barley straw to prevent algae should be very safe for fish. It will also work much better as there will be more oxygen for bacteria (meaning faster decomposition), and less chance of problems with water condition later down the road.
How long does barley straw take to work in ponds?
Depending on the type of barley straw product you’re using, the quality of your filtration, and how much aeration you have in place, the full decomposition process usually lasts between 4 to 6 months. In warmer months decomposition will happen faster, and in colder months it will be a much slower process. This is because beneficial aerobic bacteria work more efficiently in summer and much slower in winter when the water temperature drops. Hydrogen peroxide will continue to be produced throughout the entire decomposition process, and will gradually leech into water over this period. You should start seeing results from physical barley straw from 2-6 weeks if treated in spring/summer, and 6-8 weeks if treated in autumn/winter.
Remember, barley straw is a preventive method of algae control, not an algae killer, so a good result from barley treatment would be less algae returning the following year. To remove large algae blooms, always use a direct treatment method and only use barley to supplement the process.
How often should you replace the straw in the pond?
For the best results and algae prevention, adding more barley straw a few times a year is good practice to make sure there is always a low concentration of hydrogen peroxide in the water. To ensure there is always a little barley decomposing and producing hydrogen peroxide, we recommend replacing your straw every 4 to 6 months.