Duckweed control

[Matthew Arnold]

We have a pond in Shaftesbury that was dredged last winter. It had vast quantities of floating grass which was removed. We now have a carpet of duckweed covering the pond. We had a member of the public mention to us that the pond was almost overflowing because the outflow was blocked by it. I cleared the outflow but within 30 minutes it was blocked again. We have made a temporary fix with a piece of wood an inch into the water to allow water to flow but stop the duckweed. We cant use chemicals because of newts and frogs in there. I have read about netting it out and raking it out. We did have some ducks on the pond for about 2 weeks before children scared them off. What would you guys suggest?

[Charlieh]

i would suggest that in dredging the pond you have stirred up the nutrients in the silt and as such have lead to the rapid growth of the duckweed, just keep dragging it out and i suspect it will settle down.

 

you could try using a small roped floating barrage to stop the weed clogging the outfall

[Matthew Arnold]

i would suggest that in dredging the pond you have stirred up the nutrients in the silt and as such have lead to the rapid growth of the duckweed, just keep dragging it out and i suspect it will settle down.

 

you could try using a small roped floating barrage to stop the weed clogging the outfall

 

Thats the idea behind the piece of wood. At the moment its just a well placed log but will perfect it tomorrow with a 2 inch thick piece of wood held inplace by two stakes which can be removed in the winter when the flow increases.

[agg221]

I do ours with a fine mesh landing net, skimmed across the surface. Very boring job, but keeps it down.

 

Alec

[DN22 Gardening]

drop some glyphos in there.

[Matthew Arnold]

drop some glyphos in there.

 

:lol:Wish i could. Got waterlillies in it and now bloody goldfish:001_rolleyes:

[charlie6]

Put a few Grass Carp in there. They eat loads and grow fast.

[Matthew Arnold]

Spoke to the boss. We have decided to go for the semi-submerged board approach. We will be installing it tomorrow and check it every two weeks for vandalism and to clear the build up in front of the board. The boss likes the idea of Grass Carp as they are purely vegetarians.

[Charlieh]

Spoke to the boss. We have decided to go for the semi-submerged board approach. We will be installing it tomorrow and check it every two weeks for vandalism and to clear the build up in front of the board. The boss likes the idea of Grass Carp as they are purely vegetarians.

 

But they are about the worst thing you can put in the water in terms of water quality, you would be better glyphosating it rather than putting grass carp in

[Matthew Arnold]

Here are some pics of said pond and our best option put into place to hold the duckweed back but still allow water to flow. We did a pond dip and found several newts and Efts (baby newts) so plenty of oxygen still in the water.