The Lemon Fool

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?

New ponds are notoriously prone to blanketweed. I had an electronic pH meter and was regularly testing the pH. The blanket weed seem to be making the pH a lot higher (more alkaline). pH meter in the weed was higher than in the water. Began to realise that as well as sucking all the nutrients out of the water the weed was also sucking out the CO2. Other plants were also being affected by the high pH. Experimented with injecting CO2 directly into the water which helped for a little while but it's pretty expensive to do continuously. Think blanketweed is a nasty one, that transforms the water into an alkaline solution pH 10-11 which it likes but other plants don't. Strangely amphibians and fish don't seem to mind high pHs. While pulling out the blanketweed found an immature newt living in the blanketweed!

Anyway the solution I found was to buy some washbags (net bags), collect all the blanketweed I could find and stuff them into the washbags with a half brick or similar) and sink them into the deepest part of the pond. The weed cannot effectively photosynthesise when packed like that and rots, releasing CO2 + nutrients back into the pond. Other things like whatever feeds on the rotting plant matter (Dragon fly larva for example). I could see 3 or 4 of them per large bag sitting on the outside of the bags waiting for something to emerge.

The long and short of it is that new ponds do not have an established balance (the plants are usually small and struggling with adapting), so blanketweed moves in and makes it even worse. Using blanketweed as a fertliliser seems to help a lot. Perfect time to bag it up and get the decomposing/growth cycles both going. In new ponds the decomposition half of the cycle is not established.

Don't think you can entirely stop blanketweed growing but getting the decomposition side going prevents it from being so destructive to other plants.
Now have a crystal clear pond. It might matter that I used to collect a pail of water from most of the nearby ponds, in this way I managed to add sticklebacks (unwanted) but daphnia too (very small animals but a desirable base of the food chain). Snails may help too.

Sorcery wrote:Anyway the solution I found was to buy some washbags (net bags), collect all the blanketweed I could find and stuff them into the washbags with a half brick or similar) and sink them into the deepest part of the pond. The weed cannot effectively photosynthesise when packed like that and rots, releasing CO2 + nutrients back into the pond.

That's bloody ingenious! Chapeau!

Can you recall how long it might have taken for a bag-worths of plant to decompose?

-sd

I may be wrong, but I think letting blanket weed decay in the water keeps the nutrient levels too high. Clear water requires low nutrient levels.

servodude wrote:

Sorcery wrote:Anyway the solution I found was to buy some washbags (net bags), collect all the blanketweed I could find and stuff them into the washbags with a half brick or similar) and sink them into the deepest part of the pond. The weed cannot effectively photosynthesise when packed like that and rots, releasing CO2 + nutrients back into the pond.

That's bloody ingenious! Chapeau!

Can you recall how long it might have taken for a bag-worths of plant to decompose?

-sd

About a year I think, but my bags are now much depleted and still in the pond many years later.

Nimrod103 wrote:I may be wrong, but I think letting blanket weed decay in the water keeps the nutrient levels too high. Clear water requires low nutrient levels.

I suspect it depends on how much nutrients there are to start with. Best not to start with tap water which I did unfortunately. I removed most of the blanketweed quite a few times and composted it, which would have removed a lot of the nutrients. It was when I found the pH going high due to the lack of dissolved CO2 that I thought I should let it rot insitu to restore the CO2 levels.

Sorcery wrote:

Nimrod103 wrote:I may be wrong, but I think letting blanket weed decay in the water keeps the nutrient levels too high. Clear water requires low nutrient levels.

I suspect it depends on how much nutrients there are to start with. Best not to start with tap water which I did unfortunately. I removed most of the blanketweed quite a few times and composted it, which would have removed a lot of the nutrients. It was when I found the pH going high due to the lack of dissolved CO2 that I thought I should let it rot insitu to restore the CO2 levels.

Too late with my edit, so will have to do it this way :
I think there is something about the rotting process that inhibits excessive blanketweed growth. That might be why it's often recommended to use barley straw in net bags as a treatment. New ponds normally lack decomposing plant material until they are older and new ponds always seem to get blanket weed.

thanks everyone
all very informative
treatment has arrived but no indications as to best time to 'apply'

so will get on wiith it now!

as an additional question but same subject...

I have found in the shed a bag of barley straw which is years old and was bought as 'pet bedding' for gernbils etc when kids were youg
never used, never opened the bag

is that the same barley straw that folk say works at pond clearing??

mutantpoodle wrote:as an additional question but same subject...

I have found in the shed a bag of barley straw which is years old and was bought as 'pet bedding' for gernbils etc when kids were youg
never used, never opened the bag

is that the same barley straw that folk say works at pond clearing??

Can't think otherwise, barley straw is barley straw.

RC

ReformedCharacter wrote:

mutantpoodle wrote:as an additional question but same subject...

I have found in the shed a bag of barley straw which is years old and was bought as 'pet bedding' for gernbils etc when kids were youg
never used, never opened the bag

is that the same barley straw that folk say works at pond clearing??

Can't think otherwise, barley straw is barley straw.

RC

I think the choice of barley straw is simply that it's nutrient free and it will rot. You can use anything though, even tightly packed blanket weed in a bag. I used the latter because after months of pulling out the blanket weed for compost I feared I had denuded the pond of nutrients.