Even a very small pond can be a fantastic benefit for wildlife and a source of real interest in a garden. To make it easier for people to create their own small ponds, the Parish Council has bought a reasonable amount of high quality pond liner with underlay for people to buy at £5 per sq. metre. It can be available almost as soon as you contact us to place an order, which must be for a rectangular piece. The underlay is really helpful in protecting against damage to the liner by small sharp stones etc.
The first question of course, is “How much liner do I need?” You can go online and find guidance about this, but for some reason the guidelines assume that you should be making a pond that is three feet deep and has vertical sides. This inevitably uses a great deal of liner, and is almost certainly not what you want, for two reasons:
a) 3 ft (90 cm) is very deep and involves a great deal of work to remove the earth etc: the figure seems to be based on absolute protection against frost, but it would take the sort of hard and prolonged frost that we never experience in these parts to cause a problem of this sort. A maximum depth of 2ft (60 cm) seems absolutely fine.
b) many of the plants you might want to have in a pond won’t thrive in deep water, and having shallower sections is desirable.
So, to estimate the amount of liner you want, we suggest:
a) look at where you are going to put the pond and decide on its length and breadth. (Make sure this area is level – you don’t want one side of your pond to be higher than another!)
b) draw two scale models of the pond in profile – one from end to end, and the other from side to side. The drawings will show how deep you want the bottom of the pond to be in cross-section in these two directions
c) use a piece of thread or thin string to follow the line of the pond bottom in each direction, and measure the length of the from one end to the other – then convert to the real dimensions. (So, for example, if scale is 1 inch per foot, and your piece of thread measures 7½” from one side of the pond to the other then you need 7½ Feet (2.25 metres) of liner – except that you need to add 6-8 inches (15-20 cm) all the way round to create an edge to your pond that you will weight down with stones.)
It’s a good idea to include a section of bog in your design if you have room – there are lots of plants that like bog, and that insects love! If you do do this, keep the pond and the bog separate: the reason is that it’s a good idea to make a very few small slits in the liner for the bog section so that it does very slowly drain, like a natural bog, and you don’t want to lose water from the pond at the same time. Of course, the separation only needs to be a few inches where you leave the ground level above the water lever in the pond.
Note: after you have dug the pond, put the liner down and placed stones or bricks round the edge you can fill it straight away – rainwater is best, but tap water will be fine. Either way, leave it a few days to settle down before putting any plants in.
The one essential you need is something that will oxygenate the pond – you can probably get bits from friends who have ponds or we can put you in touch with someone who can spare some. Try to avoid importing duckweed – though you quite likely will in small amounts and it’s worth keeping an eye on the pond and removing any odd pieces of duckweed that appear as quickly as you can. (There is a great guide to plants for your pond here!)