How to Build a Pond in Your Garden

Prepare to build your pond

Before you start, have a good think about what sort of pond you want to make.

How big do you want your pond to be? This will depend on the size of your garden – and how much work you want to do!

Consider what sort of plants you want to grow in your pond. Different plants grow best in different depths of water, so do a bit of research. The Royal Horticultural Society is a good place to start.

Where are you going to position your pond? Ideally you want a spot that gets plenty of sunshine and doesn’t present a flood risk, so think about where the water would go if the pond overflowed.If you’re building a pond for aesthetic reasons, think about how it will look from every angle.

Gather materials for your pond

There’s no point learning how to build a pond in your garden if you don’t have the right tools! This is what you’ll need to create your watery wonderland:

A length of string or hosepipe (long enough to form the outline of your pond)
A craft knife
Building sand
A spade
A spirit level
Old carpet or pond underlay
Butyl pond liner – work out how much you need using this calculation: (the maximum length of the pond + twice the maximum depth) x (the maximum width of the pond + twice the maximum depth)
Bricks
Paving slabs, stones or turf for the edges
Water (rainwater is best)
Aquatic plants

Mark out your pond

Mark out the outline of your pond using a length of string or hose, or by trickling a line of building sand. You could do a simple shape like a circle or rectangle, or get creative with wiggly edges. If the area is turfed, remove the turf and set it aside.

Excavate your pond

Use the spade to excavate the area you’ve marked out. You might like to create shelves where you can place aquatic plants in pots. It’s a good idea to have some deeper areas, but you don’t need to go too deep – around 60cm in the middle works well.

Use the spirit level to make sure the edges of the pond and any shelves are level. Give one side of the pond a gentle slope so any animals that fall in can easily get out.

Line your pond

First of all, remove any sharp stones or lumps from the hole. Next, line the base with a protective layer of building sand. Add a layer of old carpet or pond underlay on top of the sand for even more protection against punctures.

Unfold the butyl liner, being careful not to damage it by dragging it on the ground, and spread it evenly over the hole. You may want to get someone else to help you with this – pond liners are heavier than they look! Push it loosely into the contours of the hole. The easiest way to do this is by taking off your shoes and pressing it in with your feet.

Top tip: Never put garden soil into your pond – it will give you algae problems forever. If you want to add an extra layer on top of the liner to protect it, use washed gravel or special aquatic compost.

Fill your pond

Now it’s time to bring your pond to life!

It’s best to fill your pond with rainwater, either from a water butt or as it falls. The latter may take a few weeks, but try to be patient! Tap water contains nitrates, which may give you algae problems. Once it’s full, leave it for a week or so to settle.

Edge your pond

Trim the edges of your liner and underlay, leaving a 15-20cm overlap around the sides of the pond. Cover the edges with paving slabs, large stones or turf. Bear in mind, however, that turf will require a thick layer of soil, which may wash nutrients into the pond. The grass roots will also suck up pond water, meaning the water level will drop quicker in dry weather.

Add plants to your pond

Add a range of aquatic plants to complete your pond. Go for a selection that will look attractive and perform a variety of functions to keep your pond healthy. Make sure you choose plants that won’t grow too large for your pond, and avoid non-native or invasive species.