Blanket weed!

We started our small pond last spring and it was as clear as a bell all summer and then all of a sudden about late December the dreaded blanket seed started appearing, now the poor pond is virtually covered! What is the best way to get rid of it? I don't really want to use chemicals because we have 8 goldfish in it. Does barley straw work as well as i've read? and would it be best to completely empty the pond, get rid of the weed and start again, introducing the straw? I have a one lilly and some marginal plants and the pond is serviced with an ultraviolet  filter, pump and fountain

Any suggestions gratefully received!



  • Shrinking VioletShrinking Violet Posts: 915

    Blanket weed is the very devil to get rid of!  You can never eradicate it, in my experience, but the best thing is to try to keep on top of it.

    First - use a stick to twirl it around (like trying to get candyfloss on a stick!) and dispose of the weed.  Then ensure that the pond is as clear of it as possible - and for this, yes, barleystraw bales are pretty good.  Also use watercress!  If you can get hold of proper watercress bundles (remember the bunches sold on market stalls?) chuck them in, and leave for a couple of weeks.  Dunno why or how it works - but it does!  Keeps the dreaded blanketweed at bay, and can easily be removed.  But even this is not a cure-all you still need to be vigilant, and the stick twirling may still be necessary.

  • SwissSueSwissSue Posts: 1,447

    Hallo Sloeberrysal

    We had the same problem and bought the following from Thompson & Morgan:

    It's not cheap, but worked extremely well. Try and remove as much of the weed by hand as suggested above first. You might have to do it twice a year, but can thoroughly recommend.

    There's nothing worse than a green pond!image

  • SwissSueSwissSue Posts: 1,447

    Oh, forgot to mention, when you open link click on the GB part top right (page I gave you is for overseas!) Search Pond-Wizard!

  • FairygirlFairygirl Posts: 19,776

    Verdun we bought a big bag of koi food a week before someone nicked all the fish...image

    The watercress absorbs the nutrients which the algae feeds on and starves it. It's amazing how well it can work. Verdun's right about the oxygenators -they're a must -but they can be invasive too so keep an eye on them especially as it's a small pond. As with most things, maintenance is the key.image

    to walk through a forest is to touch the past

  • nutcutletnutcutlet Posts: 24,256

    Watercress in bags from the supermarket always has a few roots or can be persuaded to grow some. That's where mine came from. It's going very well at the moment. The algae in the pond without the watercress is thicker.

  • BizzieBBizzieB Posts: 885

    Thanks everyone image this has been really useful advice.

    At my wits end as the blanket weed was smothering one of the water lily growth despite all the stick twirling,  logs of straw and clearing oxygenators to which it was clinging. Weeding the pond!

    Took out the affected lily and cleaned it up last night, also cleaned the area before putting it back.

    Other lily pads are beginning to cover the pond but will certainly buy some watercress today.

  • FoolioFoolio Posts: 80

    If u have a filter clean it out  every 3/4 days - once the levels of watercress, Lily's etc are right the pond will settle again. Take out any leaves as soon as they land and take out any old debris that has rotten in the bottom. Make sure any potted plants have stones on top to stop soil from escaping. Blanket weed feeds on nitrogen so keep out all soil from garden falling in and only top your pond up with waterbutt water no tap water as it makes algae bloom.

  • FoolioFoolio Posts: 80

    Oh and no need to feed fish - they can live on all algae, watercress, gnat larvae etc.  They won't starve, by actually feeding them food u encourage extra waste and add to your problem. I wasn't sure about not feeding fish but it works. Having started a pond a couple of years ago , it all looks after itself and I've not fed my fish - they are breeding and living healthy & happily. 

  • FoolioFoolio Posts: 80

    A bag of sainsburys watercress works the best- some fish website did a trial a while ago of supermarket cress and it came out tops,  just throw it in!  even add to a waterfall if you have one as it works as an extra filter as the water passes.  You can thin it out when it eventually gets too big & it over winters so a bag lasts a lifetime image

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