Pond slimy stuff

Thirtybyseven

These green slimy hair-like strands keep growing in my small pond. In the first picture you can see that they make the water look gloopy and frothy. The strands grow all over the other plants. If I pull all the green strands out they grow back within a couple of weeks.

What are these green slimy things? Are they bad for my pond, and if so, how do I get rid of them for good?

Fairygirl

It's blanket weed and quite normal.   As the water starts warming up in spring, it encourages it. Having around a third of the surface covered with planting helps as it creates some shade. There are treatments available, including barley straw in various guises, but I chuck in a handful or two of watercress which also works well. It uses up the nutrients which the blanket weed feeds on. 

You'll get it every year but it's just a question of managing it. If you take some out, leave it overnight on the edge of the pond, as it allows any wildlife in it to get back into the water 

Thirtybyseven

Thanks. Is it a special type of watercress? Where can I buy it?

Perhaps it's best if i just keep removing the weed - it's such a small pond i'm not sure there's room to introduce more plants!

Lyn

Buy a bag from Tesco or Morrisons.

Fairygirl

Just a bag from the supermarket - chuck it in. It's best done in spring when the water's warming up, but I've just done mine about a week ago. Water's nice and clear  

The watercress will provide a bit of surface cover - it will just float there in a clump. It will flower and seed, but it's easy to remove if it gets out of hand at all. Small ponds will tend to heat up quicker- the one I have here is the same  

Ladybird4

Hi Thirtybyseven. The common name is blanket weed and it is very common in ponds. An easy way to collect it up is by using a rake or a rough stick and twirl those around in the weed and then pull out the clumps. It won't actually harm your pond - just makes it look unsightly. One way to get rid of it is by growing more plants to shade the surface so that light cannot get through. Is that a water lily leaf I can see in the top picture? More leaves like that will stop the blanket weed growing. Some people recommend using a small straw bale which you just drop into the water and this helps reduce the blanketweed growth. I've never tried this myself so cannot say it works. What I would say is don't spend lots of money buying algae killers.

Fairygirl

Here's what mine looks like just now 30by7.

 

That's the little clump of watercress in the middle of the pic. My pond is only about a square metre of surface area

Pete.8

A fellow fish-keeper suggested I try Cloverleaf to stop the blanket weed.
It does not contain chemicals and will not harm plants/fish or your filters - and most importantly, it works. I think it comprises diatoms which coat the blanket weed and starve it of light and nutrients.
The water looks milky for about 1 day then clears. The blanket weed will be mostly gone in about 10 days.
If you have a lot of it, then best to pull out the dead b/weed to stop it decomposing in the bottom of the pond.

I find 1 dose in March usually lasts the season, but occasionally (like this year) I've had to re-dose. And if you dose early before the b/weed gets a grip, then it doesn't appear in the first place.

Would also agree re. the watercress. I grow it in the header pool and it cascades down the waterfall - and yes I do eat it

Last edited: 21 August 2016 11:03:04

Thirtybyseven

Do you mean the bags of watercress leaves that you buy for salads? I'm surprised that it grows if you just chuck it in a pond! 

Fairygirl

Yup - that's the stuff 

Thirtybyseven

Well, I never ?