Hey all,

I recently moved into a house and it has a lovely little pond about 1 metre by 1.5 metres. It's currently teaming with tadpoles and has 3 or 4 good size frogs.

I've been wondering what the green algae looking substance is onto of my pond. I know think it's Duckweed. I've been reading on the Internet and it seems as though it has many benfits for the pond, so I just need to keep in under control. The problem is that I clean 80% of it out of the pond and within two days the whole water is covered again.

The pond is located under a Maple tree so has at least 2 winters worth of leaves in he bottom. Is this rapid growth associated with so many nitrates in the water?

Cheers,
Nick

Nick Powell writes

Hey all,

I recently moved into a house and it has a lovely little pond about 1
metre by 1.5 metres. It's currently teaming with tadpoles and has 3 or
4 good size frogs.

I've been wondering what the green algae looking substance is onto of
my pond. I know think it's Duckweed. I've been reading on the
Internet and it seems as though it has many benfits for the pond, so I
just need to keep in under control. The problem is that I clean 80% of
it out of the pond and within two days the whole water is covered
again.


The pond is located under a Maple tree so has at least 2 winters worth
of leaves in he bottom. Is this rapid growth associated with so many
nitrates in the water?

Duckweed has a couple of tiny round leaves floating on top of the water,
with some fine roots underneath.

If what you have is mats of fine green hairs floating in the water, with
no leaves attached, that's blanket weed. It is associated with high
nitrate level and good light level. Light is probably not a problem with
you (the rest of us cover half to two thirds of the water surface with
water lilies and other floating leaved plants). Nitrates can be reduced
slowly by cropping fast growing plants, eg watercress.

It's recommended to remove blanket weed by twining it around a stick,
but you won't want to do this while you still have tadpoles - they get
caught up in it and won't escape back to the water.


--
Kay

Thanks for the reply Kay.

I'm positive it's Duckweed ..

Nick Powell writes

Thanks for the reply Kay.

I'm positive it's Duckweed ..


I've never worried about it. If anything, it shades the water and helps
restrict the growth of blanket weed ;-)

I think you'd need to remove virtually all of it - again, wait till the
taddies have left.

--
Kay