How to make a wildlife pond

It will need to be watertight, like a half-barrel, an old water tank or even a large washing-up bowl. It needs to be able to withstand the rigours of being outside, especially frosts.

Put your container into your chosen place while it’s empty. Once it’s full of water, it will be difficult to move. If the edges are level with the ground, more creatures can get in and out. If you leave it above ground, make a ramp or use bricks, rocks or logs to create steppingstones in and out of the pond.

Seal any drainage holes with silicone, then put a layer of clean gravel in the bottom. Don't use soil, as it will make your pond go green.

Whenever possible, use rainwater. Tap water contains too many chemicals to be good for a pond.

It is best to put plants in special aquatic plant pots (which have mesh sides). You'll also need to use a very low nutrient soil, mixed with grit (you can buy special aquatic soil for ponds).

Include native marginal plants around the edge, poking clear of the surface to give perches and cover to wildlife. Be careful to only use plants that won't grow too large for such a small space. Two or three plants is the maximum for a pond this size. Try plants such as Water Forget-me-not, Lesser Spearwort and Marsh Marigold.

For the first few months, don’t worry if you get algae or Blanket Weed (which is like strings of green gloop), get children to remove it by winding it around a stick – it’s fun!

As your mini-pond matures, all the pond creatures you’ve attracted will help keep the water clear. You may need to top the pond up in hot weather – try to use rainwater from a water butt.

Don't be tempted to bring in buckets of pond life from elsewhere. Pond creatures are great at finding ponds themselves. Toads tend to like larger ponds, but there is every chance a frog or newt will find your mini-pond, especially if you provide corridors of cover next to a pond, and add a frog and toad abode nearby.

Once your pond has established itself and some residents have moved in, its a great place to explore the world of pond dipping.

See the section above for more information on the best spots.

The golden rules for large ponds are:

• Shallow shelving margins – make sure that anything such as hedgehogs that fall in can easily get out
• Deeper areas, but you don't need to go too deep (600mm in the middle is fine)
• Plenty of submerged aquatic pondweed
• Plenty of emergent vegetation.

Get creative with your shape, using wiggly margins or a perfectly geometric shape – wildlife won't mind either way. Try doing a sketch on paper, and use string to set out your edges before digging.

While it’s possible to line a pond with concrete, we recommend using either a pre-moulded liner – usually fiberglass, they are expensive but durable, or a flexible liner – materials include plastic (PVC), butyl rubber and EPDM rubber (such as Firestone). They’re the easiest way to create a pond to the dimensions you want.

Flexible liners don't bend round right angles so use them for more naturally curving ponds. A flexible liner will come as a rectangle. The liner dimensions you will need will be (the maximum length of the pond plus twice the maximum depth) by (the maximum width plus twice the maximum depth). As a rough guide, a 3m x 3m liner will cost £50 - £100. Buy the best quality you can afford so that it won’t leak and will last longer.

Mark out where your pond is with a hosepipe laid on the ground or lines of builders' sand.

For really big ponds, you may want to hire a mini-digger to take some of the strain. Create horizontal shelves where you will be able to put aquatic plants in pots. Carefully check it is level across all sides with a spirit level.

If you are using a ready-made moulded liner, lower it into the hole to test that you have dug the correct shape. Dig a little bit more earth out than the size of the liner so that it has a bit of wriggle room. Then pack the base with a protective layer of sand, lower the liner into position and carefully pack sand around the sides.

If using a flexible liner, dig a slightly larger hole than you need (about 50mm extra all the way round and down). Then make sure you remove all rocks, roots and sharp objects from the hole. Don’t cut the liner yet.

To ensure the liner doesn't get punctured, place a 50mm layer of sand all around the hole. Then over this put sheets of man-made pond underlay, so that rocks and roots can't penetrate it.

Now unfold your liner across the hole. Remember that EDPM and rubber liners are very heavy, so you may need some help. Push it loosely into the contours. Smooth out the liner and tuck in folds as required.

You can also place some washed gravel into the base to provide cover, and protect the liner. But if you want to use soil, only ever use the special aquatic compost, devoid of almost all nutrients – garden soil will give you algae problems.

It’s best to use rainwater from a water butt, as tap water contains nitrates and phosphates which may give you algae problems.

Once the pond is filled, trim the liner that is sticking out around the outside. Tuck rocks or logs around the edge to give it a natural look and hide any remaining liner.

See the section ‘Best plants for wildlife ponds’ above for our recommendations.

In early spring plant lots of marginals onto your pond shelves using aquatic baskets and soil.

For the first few months, it’s normal to get algae or blanket weed. Remove with a rubber rake, or get children to remove it by winding it around a stick. Before composting, allow it to sit at the side of the pond for critters to escape back into the water. 

You may need to top the pond up in hot weather – try to use rainwater from a water butt. The water will look murky at first, but that's normal. Leave the pond for a week or so to settle and it should clear up.

Most of the creatures that use ponds are expert at finding new ones. So there's no need to bring in water or wildlife from other ponds, as this can bring in pathogens.