Clay lined pond

julie.wills

Hi All
A digger has just made a nice start to our new wildlife pond. It has been raining and the clay sides are retaining the water. So do I get a pond liner or do I rely on my clay soil to retain water ? How will I know that I definitely don't need to line my pond with a liner ?.

Buttercupdays

You need to ensure that the clay layer has no cracks or holes, by "puddling" the clay, (I believe by stomping around in your wellies), till you have a fairly even finish. It will also depend on the 'purity' of your clay, the absence of too many stones or grit or layers of other soils, but solid clay is not that hard to find in some parts!

We have two ponds with clay bottoms, made nearly 40 years ago,  before we moved here, and leakage has never been a problem: there is a stratum of yellow clay you could make pots with, about 9 inches down.

You will know it is good when the water starts to collect, but now is a good time to be doing it, as you are less likely to have long spells of dry weather that might lead to the clay cracking. The great thing is these ponds use no plastic, they don't have ugly liners you have to hide and you can easily shape them to suit your needs. It is easy to establish  marginal plants, but take care which ones you choose, as it is also easy for them to expand their territory and some can be hard to dig out!

SydRoy

Bentonite. Available in powder or pellet form. 

SydRoy

julie.wills said:

Hi All
A digger has just made a nice start to our new wildlife pond. It has been raining and the clay sides are retaining the water. So do I get a pond liner or do I rely on my clay soil to retain water ? How will I know that I definitely don't need to line my pond with a liner ?.

There are many types of clay. Any chance you can dig a piece up? If you can, break it in half and post a photo. 

Mr. Vine Eye

In Capability Brown’s day when they were creating big lakes for the landscape gardens, they’d send flocks of sheep down into them to puddle the clay with their hooves.

Ferdinand2000

Judging by the rain currently landing on my roof, if you just wait a few weeks / months you will have your answer and it will be too late to put a liner in if you do not need one  .

What was that Doris Day song?

micearguers

A concern is that the clay may be penetrated by roots, either from inside the pond, or from outside, e.g. tree roots searching out water.