Keeping Pond Water Clear the Natural Way

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Keeping Pond Water Clear The Natural Way

Keeping Pond Water Clear The Natural Way

Last summer my little garden pond was overcome with a mossy, weedy growth. The pond water looked green, cloudy and disgusting. After doing some research about garden pond algae, I discovered that the green stuff growing in my pond was string algae. Yuck!

Turns out that string algae growth in garden ponds is a common problem. Not only does it look terrible, algae buildup in a garden pond is bad because it can take over a small pond quickly, and eventually starve the fish and plants of oxygen and nutrients.

I was nervous when first started reading about algae growth in small garden ponds. I was worried that I would have to use a chemical for clearing my pond water, and that the chemicals might kill my fish and plants… and even worse, I would have to start over from scratch with my pond. Needless to say I was thrilled when I discovered that there is a natural solution to keeping pond water clear and getting rid of algae in garden ponds.

Barley Straw Clears Garden Pond Algae

Barley Straw Clears Garden Pond Algae

How to Keep Pond Clear Naturally

It sounds strange, but the answer to keeping pond water clear the natural way is barley straw. Not only is barley straw a natural solution for clearing out garden pond water, it won’t harm your fish or plantsĀ  – and it’s cheap to buy. In fact, I’ve read that barley straw works better to clear pond water than expensive chemicals do. Win, win, win, win!

You can find technical explanations for why barley straw works to clear pond water on the internet. But basically, as the barley straw decomposes it releases something similar to hydrogen peroxide (H2O2) which will eventually choke out the algae. Whatever the technical reason is, it works great!

Barley Straw For Garden Pond Algae Removal

Barley Straw For Garden Pond Algae Removal

You can buy barley straw at your local garden center or on the internet. You can also buy barley straw in liquid form, or you can get barley straw pellets When I bought my barley straw, it came packed in small bales that were much too large for my pond (pictured above). The package says that each bale of barley straw will treat 1000 gallons of water. My small garden pond holds only 90 gallons of water. So I made a smaller bundles out of the mesh packaging the barley straw bales came in when I bought them. I used string to tie the opening in the mesh closed.

Making Barley Straw Bundle For Pond

Making Barley Straw Bundle For Pond

It’s recommended you put your barley straw bundle in the pond near a fountain or waterfall where the water will flow through it. Once the barley straw starts to decompose, the bundle will sink so it’s no longer visible on top of the water. It takes a few weeks for the barley straw to begin to decompose and start clearing the pond water, so it will take a little longer to get results using barley straw than it would with chemicals. If you want to start seeing results faster, there are a few steps you can take now.

Barley Straw Bundle At Bottom Of Garden Pond Waterfall

Barley Straw Bundle At Bottom Of Garden Pond Waterfall

Steps for Clearing Pond Water Faster

  • Manually removeĀ algae in garden pond: Start by removing as much of the algae growing in your pond as you can manually. An inexpensive toilet brush works great for grabbing the string algae and scrubbing the sides of the pond. Ideally, you would buy a new toilet brush to use specifically for your pond; what would be more disgusting – using an old used toilet brush in your pond, or using your pond brush in your toilet!?

Related Post: Winterizing a Garden Pond

Toilet Brush Works To Remove Algae In Garden Ponds

Toilet Brush Works To Remove Algae In Garden Ponds

  • Rinse garden pond filter daily: If you have a filter in your garden pond, rinsing it daily during this time will also help to remove the algae faster.
Rinse The Garden Pond Pump Filter

Rinse The Garden Pond Pump Filter

  • Use hydrogen peroxide to help clear pond water: To help remove the garden pond algae faster, you could add hydrogen peroxide (H2O2) to your pond water. I don’t know if there’s a special formula of H2O2 per gallon of water, so I recommend doing some research for your specific pond size. My small garden pond is 90 gallons, and I added a 1/2 cup of H2O2 to the water. Pour the H2O2 over the running water of a fountain or waterfall to disperse it.
Pond Water Is Naturally Clear

Pond Water Is Naturally Clear

Shortly after adding the H2O2 and barley straw to my pond and following these steps to clear my pond water, I started to see results. In no time, my pond water was crystal clear, and it stayed that way all summer. Now I put a new barley straw bundle in both of my little garden ponds in the spring as part of my regular garden pond maintenance schedule. Since doing this, I’ve been able to avoid algae growth in my ponds, and keep the water clear. One small barley straw bundle lasts all summer.

I love my garden ponds again now that the water stays clear. It’s nice to be able to watch my fish swimming around and feeding on worms and other bugs that fall into the pond. Plus my garden ponds are constantly filled with frogs and salamanders – a wonderful sign of a healthy, chemical free garden.

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For more about garden ponds, click here… Garden Ponds

Do you have a garden pond? Tell me about it in the comments below.



  1. says

    I wonder if this will work in my fountain? I think I might try it. My fountain holds about 10 gallons of water….and it gets just gross after a while. thanks for the tips! I am a new follower!!! been stalking you on the facebook for a while…but now am on GFC too!

  2. says

    Hi Tootsie! Thanks for becoming a new follower. I enjoy your blog too! Funny you should ask about the fountain. We have moss growth on our fountain too and I just poured some H2O2 in there to see if it would work. I don't see why it wouldn't. What the heck, it won't hurt to give it a try! Hydrogen peroxide is cheap to buy.

    Good luck!

  3. says

    Cool! What a great lesson! If I ever get around to building a pond, I'll try to remember this. I love ponds. It will be fun to see more posts about yours!

  4. says

    Hi PlantPostings – Glad you enjoyed the post. Having a pond is pretty easy once you understand the basics of keeping a healthy balance so it won't become a maintenance nightmare. I have a few more posts planned for this summer about my ponds, so stay tuned! :-)


  5. says

    Thanks for the information! When we have a pond(hopefully soon), it'll be good to know about these things! I never even thought about the problems with a pond!

  6. says

    Hi RandomGardener – Funny! I never thought about problems with a pond before I put my first one in. Why would you ever worry about stuff like that? :-) I put in the small 90 gallon one as a test one to make sure I could handle it before I went larger (I didn't really go much larger as it turns out). But a pond sounds much scarier than it is, it's pretty easy to maintain once you get the

  7. Jane says

    Hi! I've also been having string algae problems with my pond and I'm looking for a way to get rid of them. A Pond Blog article advises to use beneficial bacteria to eliminate string algae. Is this different from barley straw? Do they offer the same results?

  8. says

    Hi Jane,
    No, I don't think the beneficial bacteria they are referring to is the same.

    Beneficial bacteria is an important part in keeping a good balance in the pond, along with fish and plants. A good balanced pond will prevent all types of algae growth. But when algae growth starts to take over, that's where the barley straw comes in.

    When string algae is

  9. Anonymous says

    We are really impressed with your page, and now have new direction to clear the water in our problematic 250 gallon pond. I will relay our progress and success as it happens, along with any new information we come across in hopes to help you or your followers. Thanks, Tomm

    • says

      Hi Tomm!
      Thanks, glad you found my blog. Hope this method will help you keep your pond clear. I would love to hear about your progress, and how it goes for you. Good luck!


    • Anonymous says

      I bought property and had an overgrown pondan area. We got excited my birthday came an my nephew cleaned ut pretty good then added fish. Onjy gad it for three weeks.already see grreen hairy stuff ansludge too.with aiiwe have to do I need some easy steps I have no pump just running water.please help me out.don't think its 500 gallons but Huerta guessing.I sure want to enjoy needed!

    • says

      I would start by taking a brush and cleaning out some of the algae (like I describe above). Next, I would add hydrogen peroxide (I use 1/2 cup in my 90 gallon pond, so you can do the math for your pond). You said you don't have a pump, but do have running water so just pour the peroxide over the area where the water is running into the pond. Or you can disperse it around the pond yourself.

  10. says

    Even with it being the middle of summer we just got our pond going again about 2 weeks ago with rebuilt sides and stepping stones around side because our small boulders on side of pool kept falling in. Our water garden is in the sun from noon until sundown we are trying to get more plants and fish. only have 3 small orffs and 2 gold fish now. will get more if these do ok for a couple of weeks.

    • says

      Yes, I would add barley straw and treat with peroxide now. I leave barley straw in mine year round, refreshing it every spring. It certainly won't hurt to add it this late, and it will start to break down before winter. Next spring, add new barley straw. Hope this helps.


  11. Camille Hatcher says

    Thank you, ever so much for this post! Couldn’t have been more timely . . . we bought our house in May and with it came a large koi pond (guessing about 500-600 gallon). It needs cleaning desperately and until reading your article I had not a clue how to go about it.

  12. Susan Bundlie says

    Our pond is about 20 acres. A few years ago I read an article about making an island out of barley straw and planting things on the top of it to control algae. For a water area this large, that can get to be very expensive. I’ll have to organize all the neighbors who live on the water and see if they will all chip in. Maybe next year.

  13. Heather says

    We have a 4000-5000 gallon natural pond in our yard with several koi and comets. The string algae is always a problem in the spring. We’ve treated with barley extract a couple times but it didn’t seem to having long lasting effects and ended up adding the chemicals to control the out of control algae. We added several water plants which seemed to help some. Now that I’ve read your article, I’ll try the barley bale from my local garden center and the peroxide as well…it’ll be a lot more than a 1/2 cup :-) Thanks for the ideas!

  14. Deanna Oster says

    i was wondering if timothy hay would work the same way. i have many goldfish in my 90 gallon pond. would the peroxide hurt the fish?

  15. says

    Hi Amy! I am excited to try this!! Gonna purchase some barley straw today! I was using chemicals, and wanted to find a natural way of clearing my pond of guck! Thank you for this post!!! Aloha, Jen

  16. Dani says

    I am thinking of doing a couple of recycled tire ponds in my backyard but I have dogs and I live in MN so breeding bloodsucking mosquitoes is a problem. Do you have any recommendations? I don’t plan to do fish as they wouldn’t survive the MN winter in such a shallow area. Will I need something to keep the water moving? I’d use chlorine but it’s not safe for the dogs. Any suggestions would be great

    • says

      I am also in MN and I use a stock tank heater to keep the water in my ponds from freezing to the bottom. Mine are in the ground though, so if yours is going to be above ground, the stock tank heater probably won’t keep it from freezing. I recommend buying inexpensive goldfish. They will eat all the mosquito larvae and are cheap enough that if they don’t survive the winter, you can replace them every year (they’re like $.10 or $.25 cents a piece at the pet store). But, the goldfish will hibernate and survive the winter as long as the water doesn’t freeze solid. I’ve had them survive 5+ years in my small garden pond.

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