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celia2celia2 Posts: 21

Has anyone discovered a way of eliminating duckweed from a garden pond, or at least restricting its growth ?  ! !



  • marshmellomarshmello Posts: 683

    Yes, reduce the amount of sun it receives. Your pond must be in full sun if the problem is bad. First, pull it all out with a net, then shade the pond with either tall plants or some sort of screen.

    I have two ponds, one located in full sun - loads of duckweed. It stays cos I like it.


    the other is shaded, this one never grows any more then a dinner plates worth.

  • DaintinessDaintiness Posts: 983

    I control it by scooping it out regularly but even if you get rid of it completely for a while - it usually is reintroduced through the wildlife visiting your pond.

  • celia2celia2 Posts: 21

    Thanks marshmello.  The goldfish love sunbathing and the rockery needs some sun unfortunately.  The current tactics are to net a lot of it off, and then fire the hose at the rest of it to banish it to one end.  A bit temporary but a good way of venting my frustration ! 

  • celia2celia2 Posts: 21

    Funny you should say that Daintiness, yesterday one of my frogs was hopping around the rockery almost totally covered in duckweed.  I wondered what it was !

  • RobotRobot Posts: 137

    When we had our last pond and were buying plants we had to rinse out the plants very carefully as they had bits of duckweed stuck in their roots but occasionally a bit got through.  So, we installed a skimmer and pump from an old above ground swimming pool - no digging required as the water was skimmed off the surface and went through the filter and was pumped back into the pond via a hose - just as if it was on the swimming pool.  Hubs had to make a bracket to get the skimmer into the water but that was easy enough. It was portable so didn't have to remain there all the time.

    Just an hour or two now and then would clear the pond of any duckweed, leaves and rubbish which had floated down and inbetween we would use a net to clean the surface.

    It's just an idea and may help.



  • celia2celia2 Posts: 21

    Thanks for that Robot.  Have you thought of setting yourself up in the business of de-duckweeding ponds ?   You'd make a fortune ! 

  • RobotRobot Posts: 137

    I wouldn't make a fortune now - I've just told everyone image

    We got our pump and skimmer from the classified ads and it was peanuts as the owner had a leak in his pool which he couldn't fix so dumped the pool and just sold off the pump etc.  I'm sure you could do something similar.  If you need further info on how to set it up etc. let me know and I'll get hubs to tell you what he did.  I wish I had some photos.


  • RobotRobot Posts: 137

    Found this on YouTube which shows the skimmer being put into a pool.  Obviously the hose doesn't screw into the side of your pond, it comes out from under.  It's exactly the same make we used.

  • celia2celia2 Posts: 21

    Looks a wonderful piece of kit - wonder if it slurps up goldfish !  image  I have very curious fish - baby ones too.  The waterfall creates a slight current which lodges duckweed in the oxygenating plants so netting doesn't capture it all, so have just been hauling out a mountain of oxygenating plants.  What size is your pond ?

  • RobotRobot Posts: 137

    Your fish should be fine as the top of the skimmer bobs up and down with the water level and stays on the surface.  Our pond had koi, goldfish and fry - plus the usual assortment of pond skaters etc - and you can't get more curious than koi and they would have a look when it was on and that was it.  Unless they jumped in then no worries.  Besides, they would be caught in the basket and not get all the way to the filter.

    We would push our oxygenating plants into the water and wiggle them a about a bit and the duckweed etc would just float out.  If you feed your fish don't do it before you skim or all the food will go down the skimmer (obvious really).

    We used to have another pond which was pristine - no soil, minimal plants etc so that the koi were living in crystal clear water - a system which a lot of koi enthusiasts prefer - and we had a skimmer which was specially made for the job plus a shed load of filters and pumps.  I wanted a more natural pond but we installed the bottom filter system before thinking about a skimmer so came up with the swimming pool idea.

    Someone should invent a fish which only lives on duckweed and then there wouldn't be a problem....

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