Pond planting - use only gravel?

[King Edward]

Does anyone have experience planting up water plants in baskets containing only gravel (and/or sand), rather than in soil/aquatic compost? Thinking about things like Water Lilies, Typha angustifolia, Butomus, Sagittaria and various other common garden pond species. At the moment, there are currently some plants growing in baskets filled mainly with topsoil, which I think is causing too much nutrient input and algal growth, so I'm planning to replant these to try to sort the problem out.

[Red Robin]

My Iris's were given to me already in baskets and from another wildlife pond so I have no idea what kind of earth is in them. They do have plenty of gravel in the top though and new growth is looking very healthy.

Isn't a certain amount of algae a good and natural thing? I suppose that it depends how manageable it is - I'm lucky as my pond is small and so it's easy to control.

Is your amount of algae overwhelming? How did you assess an excess of nutrients?

[nightshade]

My plants just sit in the baskets with a few pebbles on them and have been that way since they outgrew their baskets a couple of years ago. I do have fish
in my pond.

[Kayleigh]

I would suggest re-potting the plants in aquatic compost as normal garden soil is rich in nitrates and this is why you are having problems with algae.
I think water lilies are hungry plants so need the aquatic compost but not garden soil..
Sand would just wash away this why you put gravel on the top of the planted up baskets.

[RosieB]

I also use aquatic compost, inside hessian so the roots can be controlled, then I add stones on top everything settles nicely like this for my pond. Good luck!

[King Edward]

In reply to some of the posts above, last summer there were very large mats of floating blanketweed which looked pretty terrible, suppressed the submerged vegetation (mainly Hornwort), and grew back quickly after being removed. I'm fairly certain about the cause of the problem (excess nutrients, mainly from the soil), and I'm aware of the general advice to use aquatic soil or subsoil rather than topsoil. My question is less about diagnosing the problem and more about whether anyone has experience of gravel-only growing.

Possibly Kayleigh is right and water lilies do need some kind of soil to grow in. Perhaps I'll have to experiment with gravel only potting - maybe not for lilies but I do think it might be useful for some of the marginal species.

[Red Robin]

Originally Posted by King Edward

In reply to some of the posts above, last summer there were very large mats of floating blanketweed which looked pretty terrible, suppressed the submerged vegetation (mainly Hornwort), and grew back quickly after being removed.

....The blanket weed I get doesn't float around but 'grows' on the sunny side of my pond liner like barnacles on a ship's hull. However, the water snails and hog lice seem to graze it, aided by a giant human hand (mine!) removing excess.

So, how does one test one's pond water for levels of nutrients? [EDIT: Apart from observing the quantity of blanket weed]

[Jim Ford]

Originally Posted by Red Robin

So, how does one test one's pond water for levels of nutrients?

You check to see if blanket weed is growing in it!

;^)

Jim

[Red Robin]

Originally Posted by Jim Ford

You check to see if blanket weed is growing in it!

;^)

Jim

....

Yes, I thought about that when I asked (my earlier post has now been edited).

Agreed that it's the most natural and easiest way but are you saying that if the nutrient levels of a pond are perfectly balanced then no blanket weed should be present at all? Isn't it just like any other 'weed' in that it's a plant growing somewhere undesirable to us humans? (as well as being a useful 'thermometer'). Does blanket weed serve serve any useful purpose for the inhabitants of a pond?

[Jim Ford]

Originally Posted by Red Robin

Agreed that it's the most natural and easiest way but are you saying that if the nutrient levels of a pond are perfectly balanced then no blanket weed should be present at all?

Nah - it was just me having a cheap shot!

;^)

My experience with 'small' artificial ecosystems - fish tanks, ponds, greenhouses - is that it's difficult to achieve a stable system without extreme swings. These ecosystems are usually less 'complete' and have fewer controlling and stabilising factors. In the case of a garden pond, it's unlikely to have eg carp, tench, bream and waterfowl keeping the blanket weed under control.

Jim