As discussed a couple of months ago, I'm now about to empty and then
re-line our [leaking] pond.

I'll remove all plants, drain most of the water, then gently empty the
residue, bucket by bucket, through a garden sieve into an old
plasterer's bath, and put all creatures found into a separate trug full
of pond water.

So far so good. But this year we have been plagued with blanket weed
like never before. If I replace the plants, and (say half of) the old
water into the new liner, am I going to be stocking it with blanket weed
for next year? (!!)


BTW this year I spent £15 on a bottle of barley extract, and applied as
directed. It might (possibly) have slowed it down, but it emphatically
did _not_ get rid of it. I am beginning to think that all such
treatments are quack remedies: in any case they work so slowly, that you
wonder if the weed has slowed down / gone away of its own accord -(

Cheers
John

On 31/08/2020 14:25, Another John wrote:
As discussed a couple of months ago, I'm now about to empty and then
re-line our [leaking] pond.

I'll remove all plants, drain most of the water, then gently empty the
residue, bucket by bucket, through a garden sieve into an old
plasterer's bath, and put all creatures found into a separate trug full
of pond water.

So far so good. But this year we have been plagued with blanket weed
like never before. If I replace the plants, and (say half of) the old
water into the new liner, am I going to be stocking it with blanket weed
for next year? (!!)


BTW this year I spent £15 on a bottle of barley extract, and applied as
directed. It might (possibly) have slowed it down, but it emphatically
did _not_ get rid of it. I am beginning to think that all such
treatments are quack remedies: in any case they work so slowly, that you
wonder if the weed has slowed down / gone away of its own accord -(

Cheers
John

Blanket weed (spirogyra) needs particular conditions to survive.
Eventually it alters those conditions and dies.



--
“when things get difficult you just have to lie�

― Jean Claud Jüncker

On 31/08/2020 17:28, Chris Hogg wrote:
Blanket weed, Spirogyra as TNP says, is an alga, and as such is a
simple plant. Plants thrive on nitrogen, nitrate to be more specific -
it's one of the three components of most garden fertilisers. If you
have a lot of nitrogen in your pond water, blanket weed will flourish.
There are several potential sources of nitrogen in a pond: run-off
from nearby flowerbeds that have recently been fertilised; rich garden
soil that has been used for potting up pond plants; lastly, and
probably the commonest - fish crap. That last comes from being
over-generous with fish food. When I had a pond in my previous
property, I never fed the goldfish. They never got very large, but
survived and bred quite happily, the water didn't go pea-green in
spring and I had very little blanket weed.

There's another source of nutrients: Tap water. If you have to top up
your pond in hot weather as the water evaporates all the nutrients get
left behind. There isn't _much_ nitrogen in tap water, but there is some.

(I must rig up that rain water diverter...)

Andy