Barley straw is a great way to help control or prevent algae in lakes targeting single-celled algae, aka green water, Blue-Green Algae and filamentous algae, aka blanket weed. Using barley straw in whatever forms doesn’t kill algae and its reduces it and in the long run (years).
Most the time you’ll see fisheries putting a whole bale of barley in to the lake or make straw “sausages”, while those are ways to tackle it; it has its down sides. Its a slow process, decomposition of barley straw whole bales can feed nutrients to weeds, causing an outbreak and can produce organic waste in a lake which is counter productive. If your lake is already struggling with water quality issues, a whole bale/sausages will only add to the issues.
Then there is aquatic “dyeing” that turns the whole lake blue or black, While is does work for most who do use this stuff. I’m not a fan of that when our lake has gin clear water that I’d like to maintain.
Don’t forget that Barley straw is not effective against higher plants, such as duckweed, watermilfoil, or pondweed. It’s also important to note that eradicating any aspect of food can have ecological implications.
Bonus with extracting barley concentrate, it lets you target problem areas directly as well as the entire lake/pond, lets you create and store the concentrate to use when you need it and can start seeing results in just weeks. Unlike bales which can be an eye sore stuffed in the lake, the faff or mess of dealing with bales and also having to make sure they don’t touch the bottom of the lake. Then the cost factor, to buy Barley extract “ready made” can be from £55+ per 25Ltr container, this system can produce up to 650 Ltrs of concentrate if you use a whole IBC tank for the price (after set up) of 1-2 18kg bales of barley straw which cost me £4 each!
How does it all work?
Here are details of decomposition process if as a whole bale in your lake or in an IBC:
– Barley straw, or barley extract, is placed in water and slowly begins to decompose. During decomposition the cell structure of the barley begins to break down, the rate of breakdown is dependent on water temperature and oxygen content. Beneficial bacteria will work faster in warmer temperatures and well-aerated water = you’ll see faster results from barley in summer compared to winter. After a few weeks in the water, decomposition changes from being bacteria dominant to fungi dominant, leading to “rotting”.
– As fungi eat away at the remains of the barley material, humic acid is produced, which is the first big step towards algae control. As the acids leech into the surrounding water it reacts with oxygen and sunlight, becoming more and more unstable and eventually turning into a super-oxide radical which leads to Lignin.
– Lignin is a powerful algaecide, when produced from correctly dosed barley in a low enough concentration to be safe for fish and still be effective as an algae deterrent. As this is more stable in fresh water compared to salt water, it stays effective for longer and requires less frequent dosing.
When to use? Starting late winter/early spring and dosing your lake in 10 week cycles all through the growing season. Barley does not kill existing algae, it stops new growth. So its important to start this at the right time of year.
Location, Location, Location. For the best results, make sure your IBC is in full sunlight & the solar panel gets the best angle of sun all day.
How to extract the concentrate: The process takes 4-7 weeks depending of time of year. Colder months takes 6-7 weeks, longer versus summer at just 4 weeks, so plan accordingly.
– Add a bale of Barley straw in to the IBC, you need to break the bale up into loose straw, rough guide is fill 2/3rds of dry lose straw.
– Add rain or lake water to 3/4ths. Do not use tap water as the chlorine will impact the bacteria.
– Press down the straw so it all gets wet
– Switch on the air pump.
– Agitate/mix the straw minimum twice a week, every 1-2 days is best to make sure it all gets wet.
– Test for Hydrogen peroxide. 2 ppm is ideal. Also use this to check your stored liquid is still useful.
– You are looking for a “Strong tea to Dark Beer” look to the water and yes it may whiff a bit. When ready, you can decant the concentrate in to suitable containers. Fill to the brim getting rid of as much air as you can. *Make sure you wear gloves as this stuff is smelly to get off you I am told*
This helps it keep for longer, the average “keep” time is around 4 months when kept out the sun.
Dosage: The 1st dose 10-12 Ltrs per acre with aprox average depth of 6ft (more if average depth is deeper) on week 1, then 2 Ltr per acer per week for the next 9 weeks and then repeat the cycle. You may want to increase the doses if your water is coloured. You can mix the concentrate with water to help spread it better, 1:5 with water. Applying it to the water: easiest way is to just pour it into the lake/pond directly, ideally upwind to let the wind mix/move it around the lake for you. Work smarter, not harder!
How to build all this and list of what you need.
What you’ll will need + links:
– Safety Glasses and Gloves.
– Cutting tools eg Angle grinder, hack saw etc.
– 1 x IBC 1,000ltr tank, must be “food grade” or had Ad Blue can easily be found.
– 1 x solar air pump with 2 air stones LINK. £19. *This one switches back on following day with no need to switch back on. (I have 2 of these running).
– Tap adapter for the IBC if you don’t want to use a pump LINK.
– 16-18kg dry bale of Barley straw from your local farmer.
– Several 20ltr containers & must be stored out of direct sun.
– Water, also plan how you will get the water into & out the IBC. I used a 12V bilge pump which filled our tank in 20-30 mins & plan to use the same to decant.
– Remove the top locking bars off the IBC so you can remove the plastic tank so you can cut the top off or create a lid to keep the rain out.
– Cut the metal cage down so you can access the lid, I used a angle grinder & then files the sharp edges off.
– If you choose to keep the top as a lid: Add hinges, I pop riveted mine on using penny washers on the inside, you can use bolts instead.
– Add rubber edging if you feel the edges are sharp.
– Bolt the Solar air pump to the IBC, drill a large enough hole through the lid for the air hose & be sure to point the panel to the sun. Fit the air stones onto the air line & make sure they sit at the bottom.
All set up & bubbling away now. I cut the tank down to 500 ltrs as our lake is only 2 acres & we don’t need 650 ltrs of extract! max we need for 3 cycles of dosing is 180 ltrs, as it is there is 400 ltrs of water in it so will have some going spare! I am planning on doing 1 more “brew” October time to start using in late winter/early Spring next year.
Couple things I added to our tank is a “skirt” to stop the rain getting in & diluting the mix, some rubber edging to make the tank safer & a lock as our lake is accessible by the public & don’t want them opening this up mid brew! Over the coming weeks I will also build a “dead hedge” around it so its less of an eye sore, the hedge needs to be far enough away to still get full sun.
5th April 2025:- Its week 6 & I have not seen the water turn any darker. I am told that it is indeed ready to use, I will leave it 1 more week for good measure.
Thank you to Gary Bayes for the information and James Bradford for putting me on to this method.