Watercress and Barley Straw?

[jaelen]

Hello all- I've got more pond questions... this time about keeping it from going so green.

I've done a search and read back through some of the previous posts- I realise that going green and murky seems to be part of the process of the pond readjusting itself after being cleaned out completely back a few months ago, but I don't want it to revert back to being a total swamp!

Only a few leaves have fallen in and gone to the bottom- I've been fishing most of them out with a net, but I did let some go down since the frogs do on occasion hide under them.

It's only over the past week that it's gone REALLY murky- with a bit of a scum on top. I'm guessing that my newly-planted pond plants haven't had a chance to get fully established yet, and so can't compete with the algae. There is no running water or fountain in the pond... how should I go about trying to oxygenate it, so that the plants don't die?

I thought about filling a watering can from the pond and pouring it back in- and I read somewhere that Kayleigh recommended watercress... I bought some in those little plastic containers from the supermarket a few days ago, but am not sure exactly how to use it- at the moment it is just sitting in the hanging pond basket. Do I chuck it in, (with the dirt on the roots?) and let it float?

Also, someone else mentioned barley straw, so I'm watching a bundle of that on eBay, but wanted to find out more before I got it- is that a good method, if anyone has tried it?

Thanks for any advice or words of wisdom- any help is much appreciated!

[Kayleigh]

Hi jaelen,

I think your mixing watercress with salad cress the little leaved stuff in plastic containers, watercress comes in plastic bags and I just throw a bag in it is frost hardy so will grow all winter.
Watercress has no soil on the roots.
I threw in 15 bundles of oxygenating native plants similar to a native (Canadian poindweed) I cant remember the name, but I separated them from the weights so they are free, they will be enough to oxygenate the water along with the other plants I have in there, a waterfringe the frogs love to sit on or hide in and 2 water soldiers they are like underwater spiderplants and reproduce like them too they too are oxygenators.
I have scum on the top left from the birds as they bathe but I don't think its anything to worry about.
As long as you have enough plant in there your water should be fine it will start to look bare soon as the plants start to sink to the bottom for the winter.
This is normal..
I take some leaves out that are on the top but leave some in as the snails and water slaters live on them.

I used barley straw and tbh its a waste of time it did very little the watercress is far more affective.

[King Edward]

What kind of algae do you have, Jaelen? Is it green water, or blanketweed? If green water, then I'd just leave it and it should clear before very long. Either it'll be eaten by copepods/daphnia, or it'll run out of nutrients and die. Especially at this time of year when it's getting colder and less sunny. I wouldn't worry too much about oxygen levels - if anything, stirring up the water could even increase algal growth by releasing nutrients from sediment.

[jaelen]

Ok, thanks for that Kayleigh- yes, I didn't understand the difference between the types of watercress... I got some of the bagged and put that in the pond just a little while ago.
The two little bunches I put out a few days ago aren't doing too badly- but I expect the first frost will kill them off.

King Edward- it's like green algae- the water's gone quite murky and there's now a green thin scum on top; it's not blanketweed, thank goodness (we had duckweed prior to emptying it two months ago, but fortunately that's not come back yet.)

I suppose it's just a matter of being patient and waiting for the oxygenating plants to establish and start balancing things out, like you said. Thanks for your replies!

[King Edward]

It's not necessarily the plants. Our new shallow pond I put in earlier in the year went fairly green for a short while, but then cleared and has been sparkling clear ever since. Plants haven't established very well at all yet, so no credit to them. There was a fair growth of blanketweed, a lot of which I removed, but I think the main credit for the clear water goes to the hordes of Daphnia eating it (literally millions of individuals). These multiply very quickly when there's enough food, so long as you have some to start with (doesn't have to be very many).

I haven't removed any autumn leaves yet, on the bases that they're providing a good habitat and that the pond could do with a certain amount of sediment on the bottom for plant growth, plus being shallow and well oxygeneated with falling water levels in the summer months I suspect a lot of the organic matter will oxidise away during the coming year.

[JohanJ]

Hello Jaelen,

Is your pond in full sun? Reason I ask is that this is much more of an alterable contributory factor than messing about with watercress or barley straw. Both of the latter can and do help in different ways, but at the end of the day if you've always got that punishing sunshine heating up your water then you might gain a lot by planting some bushes/overhanging trees/adding some sort of screening then either of those.

Watercress is good stuff, it grows roots from leafnodes so you don't need it to be rooted for it to grow. I bought mine from a watercress farm and 4 pots of that is one of the factors that's kept a well stocked fishpond crystal clear all summer (no nitrates or nitrites on sequenced tests). But mine is also in the shade, so it doesn't give algae that much of a chance to get going.

Barley straw is the folksy way to treat it, it does work to a certain extent but I'd have to say that it's not as effective. I used to use this for years until I saw the light -- it depends on the stuff rotting which does chemical things in the water that makes algae have a hard time. If you can, get barley straw liquid (which is the active stuff once it rots, rotting can take a few weeks you see).

I've actually done something somewhat radical in the fishworld which is not worry about the leaves on the bottom too much and just leave them there. Since I have absolutely no nitrate or nitrite readings, it seems churlish not to give the few insects that have eked out a survival in my pond amidst the predatory fish a place to hide in.

[Kayleigh]

The water fringe leaves float on the top of the water like little water lily leaves and are perfect for a smaller pond they block out some of the light, you really need the plants to cover maybe half the water surface.
I have a couple of marsh marigolds round the edge too their leaves also provide some cover.

[King Edward]

I think Jaelen's pond is quite shaded already, as there are trees beside it. So I don't think algal 'remedies' that involve reducing the amount of light reaching the water are a very good idea, whether by putting more plants around the pond or by floating-leaved plants. Especially since it's now the middle of October, which is quite a dim month.

Looking at our other new pond recently, fallen leaves seem to be very popular with damselfly nymphs which use them to hide under.

[lilyrose]

My (small) pond rarely clears in the summer months, sometimes being a deep velvety green and sometimes just green (but no blanketweed) but the fish seem happy. It clears over the winter months. My mother's small pond is in full sun all day and has lots of goldfish in it, a few marginals and canadian pond weed and is always crystal clear.
I've tried barley straw to no effect and will now try watercress.
Where do I get daphnia as I've never seen any that have arrived naturally?

[King Edward]

You could add Daphnia, but the fish will eat them.