The Lemon Fool

I have also put on 'natural world' board, but I dont know how busy that board is
so am asking here as well
***
I have made 2 ponds in garden during the summer
no fish but I bought some plamts online from recognised supplier

both ponds are regularly full (well have a lot) of blanket weed
I read that this is due to imbalance of PHs (whatever they are) and affects new ponds mostly until a balance is recheached

so OK I am not in any hurry with winter coming and so on, but I would like to have nice clear ponds for the Spring for wildlife to move in!

I have ordered som blanket weed treatmet and am waiting delivery....but...is there a correct...or best tie to trea the pond or is it done when affected?
(the treatment ordered might say as much on box when it arrives, but the 'pitch' at sales did not so advise)

any thoughts please?

If you have not already done so, have a look at RHS advice on this topic:
https://www.rhs.org.uk/advice/profile?pid=162

You can't have an"imbalance of PHs". pH is the chemical measure of acidity. On a range from 0 to 14 pH=7 is neutral. Your pond has just one pH, which can be measured with a simple meter purchased from a garden centre. Ponds tend to be slightly acid because rain water is slightly acid due to CO2.

The main cause of blanket weed is too much nitrogen from fertiliser run-off. If you scoop out the blanket weed that will reduce the problem. Also commonly recommended is to add a bundle of straw; also make sure you have some water snails. And if the ponds are in full sun, consider adding a water lily to shade it with its large leaves in the summer.

Nocton wrote:Also commonly recommended is to add a bundle of straw.

Specifically, barley straw. As used since time immemorial! For example, https://www.pondkeeper.co.uk/pondxpert- ... or-2/p3498 . More than you're ever likely to need for eight quid.

BJ

Doesn't pond weed tend to be associated with non-aerated water?

It's the base of a different ecosystem. Not so great for fish, but the frogs (and tadpoles) might like it.

(speaking from ignorance )

Although the subject says 'pond weed' the OP is talking specifically about blanket weed, which is actually algae and a main cause is too much nitrogen in the water. That is usually caused by fertiliser run-off from agricultural land or gardens. Fish tend to make it worse due to their poo.
Oxygenation may help as the algae cause de-oxygenation, but best to start with the causes before the treatment.

Nocton wrote:Although the subject says 'pond weed' the OP is talking specifically about blanket weed, which is actually algae and a main cause is too much nitrogen in the water. That is usually caused by fertiliser run-off from agricultural land or gardens. Fish tend to make it worse due to their poo.
Oxygenation may help as the algae cause de-oxygenation, but best to start with the causes before the treatment.

Is that the same as the blue-green algae we're warned about in lakes and lochs? Many in Scotland are reporting worse than usual occurrences this year, unusually persisting into the colder weather.

Scott.

swill453 wrote:

Nocton wrote:Although the subject says 'pond weed' the OP is talking specifically about blanket weed, which is actually algae and a main cause is too much nitrogen in the water. That is usually caused by fertiliser run-off from agricultural land or gardens. Fish tend to make it worse due to their poo.
Oxygenation may help as the algae cause de-oxygenation, but best to start with the causes before the treatment.

Is that the same as the blue-green algae we're warned about in lakes and lochs? Many in Scotland are reporting worse than usual occurrences this year, unusually persisting into the colder weather.
Scott.

No, there are hundreds of different algae. As far as I know the typical pond blanket weed is not poisonous

Nocton wrote:No, there are hundreds of different algae. As far as I know the typical pond blanket weed is not poisonous

Helluva complicated subject. How are you with Venn diagrams?

Blanketweed is one subset of what they call filamentous algae. And a small part of the filamentous group are also cyanobacterials, although most aren't.

Other cyanobacterials belong to different groups, which have subsets of their own.

As Nocton has said, the cyanobacterial (blue-green algae) group is vast, and there are many different strains in every country. Some of it is harmless - the Chinese make soup out of it! While others will do you no good at all. Dogs have been killed in Britain after swimming in some kinds of green-blue algae, and others will make you feel ill, but other cyanobacterials won't harm you. Although they may starve the water of oxygen.

One blue-green algae is nostoc, which is a seaweedy-looking growth that you find on limestone and limestone gravel. It looks hideously slimy, and it's a cyano all right, but it isn't poisonous. Usually! They've got a variety in New Zealand at the moment which seems to have morphed in some way, and the rumour is that the widespread use of glyphosate may be implicated in its evolutionary success.

Image source.

There, that's more than you probably wish to know about algae. Coming soon to a pond near you!

BJ

We have had a garden pond for about 15 years. It's kidney shaped, about 3m long - I don't know whether that counts as "small". For the first 3 or 4 years I dutifully put barley straw in but then I gave up and although we get a bit of blanket weed now it's nothing to be worried about, I just fish it out occasionally ( a cane with a split end, something jammed in to open up the split then twirl it round in the water ) and it's fine.
We have plenty of lily leaf coverage and I think that's the key. Keep the light out and let the pond mature for a few years.

Good luck
ma1co1m

thanks everyone
treatment has arrived but no indications of best time to apply

so I will get on with it and keep fingers crossed

If they are new ponds them my inclination would be to not do anything, or just fish the worst of it out. Watch out for things like dragonfly larvae the may be living in it. You may not like algae, but it's home to somebody! It will probably sort itself out on it's own in a couple of years as other plants grow to provide shade, snails breed or appear to eat some of the algae etc.

I hope the pond is for wildlife, and therefore whatever the algae-killer is made of, it's probably not desirable for other pond residents.

Try not to let too many nutrients enter the water; minimise topsoil falling in, avoid applying fertiliser to neighbouring bits of garden.