Building a Garden Pond

image of garden pond with deck

The addition of a pond to a garden is nothing to sneeze at, the workload can be arduous, but if you’re avid about wildlife then there is no surer way to attract it close to home.

As with any major construction the success of a pond is determined in the planning phase before your spade ever bites into the soil.

As always, your first consideration should be the garden as a whole and what, if anything, a pond could add to the garden. With this mind it is paramount you consider the dimensions of both carefully. While, in theory, a water feature teeming with life might seem an attractive prospect, it can easily become an eye-sore if incorrectly proportioned or styled to the space surrounding it.

In other words, the garden you saw at Chelsea, complete with miniature waterfall and rustic rocky outcroppings, while gorgeous at Chelsea, may not fit in with the formal or contemporary garden you have at home.

Another thing it is important to note is the presence of children or small animals either now or in the future – even an inch of water still poses a threat if underestimated. Also consider the current role of your garden, if you have children of an age that a pond is no danger, question whether they’d appreciate it. A medium sized body of water is no kind of football net!

The most effective site for your pond should be based on where it can be viewed – ideally an area with clear visibility from the most popular areas of the garden and house. This will also provide visibility when a child or pet is near the pond site.

During the winter months your water and plant life will fall prey to prevailing winds and in the summer to evaporation, so you should perhaps site it near to a hose pipe, but away from raised areas.

Another note, one oft overlooked, is to avoid putting it under deciduous trees, as their foliage will settle on the surface and rot, ultimately fouling the water.

Next you must decide on the general structure, as, depending on your preference, certain flora and fauna will require different conditions in order to sustain themselves. For example, if you wish to cater to water-life, then you should forget sustained wildlife, as the former will make prey of the latter! A fresh water pond populated by Koi carp would provide no safe haven for frogs or their offspring, similarly an amphibian population would require different climate conditions to a family goldfish. Thus, it is important to tailor your initial dig with an eye to what it is to support.

image of frog

If frogs are to spawn there, then it is necessary to provide them with varying depths of water as they prefer to spawn in the shallows while tadpoles and fledglings will require deeper water to mature in. If fish are the primary concern, then a depth of at least of two feet should be observed so that in a harsh winter there will be sufficient depth of water that the whole pond does not freeze. The same goes for unusually hot summers – so that there are cooler depths for them to retreat to.

image of bird

If you wish to attract smaller land/air based animals such as hedgehogs and birds, the incline of your pond edge will also dictate how hospitable it will be to those who need somewhere convenient to bathe and drink. A pebble ‘beach’ also gives your water based creatures somewhere to bask.

image of koi carp

Also remember, if you wish to pursue a fish rich pond, be prepared for the cost of meticulous filtration.

For marginal plants to integrate into the land/water border, a shelf 30cms wide by 30cms deep is suggested for lining with planting baskets and remember only to use aquatic compost, as normal compost will encourage algae growth. This will also provide a secondary site for frogs to lay their spawn.

The inclusion of pond plants is essential to the aesthetic success of your pond. Without them, algae will take over the waters surface and turn the pool into a soup of dead plant life, not to mention strangle the surrounding area of the garden. Take care to avoid invasive species though. 

We’d recommend the introduction of marginal plants such as 

image of marsh marigold

the Marsh Marigold (Caltha palustris), with its yellow buttercup flowers,

image of arrowhead

and Arrowhead (Sagittaria sagittifolia) with its arrow-shaped leaves and large white flowers. 

image of sweet flag

To provide some height and places for dragonflies and damselflies to perch, the Sweet Flag (Acorus) genus would be good, 

image of yellow flag iris

together with the Yellow Flag Iris (Iris pseudocrorus). 

Water lilies are the quintessential pond plant and their large leaves provide shade and shelter for fish and other pond life. Include some oxygenating plants too, 

image of water violet

such as the Water Violet (Hottonia palustris) 

image of canadian pondweed

or Canadian Pondweed (Elodea canadensis) to keep the water clean.

Now we’ve covered the why and what of your pond, let’s talk about how it will be built. One of the primary decisions you make will be what type of lining to use and this is pivotal as the lining will provide the pond’s shape and stability, make it waterproof i.e. prevent leaking, and also decide which species of plant and animal life it will be able to support. Simplicity is key for whatever size and shape of lining you decide on as you’ll have to this match in your dig!

The three most popular options are cement, preformed moulds and waterproofing material (butyl liners), each with various pros and cons.

Cement is obviously the most sturdy and will guarantee longevity in the shape of your pond as well as protection against the elements. However, it is hardly the most attractive way of lining your pond, nor the easiest to remove later on. Also, while it will be delayed by the strength of the initial material, inevitable degradation of the concrete by plant roots will be difficult to maintain and more time consuming than a plastic liner.

The plastic shell would be the most attractive option to a novice pond builder as it guarantees a shape, a static structure around which to base the rest of your design, however for a first timer I would not recommend this option. The preparation of your hole must be well nigh flawless to ensure its continued integrity, however the variety of shapes and sizes that these come in do give a wide variety of habitats, as they will provide built-in artificial land slopes and shelving.

The third, and most flexible option of lining, is butyl, as it can be trimmed to any size and shape by hand. However, as always, quality will be dictated by price. It should be noted that the ground needs to be very carefully prepared by removing all stones and a good sandwich layer needs to be laid between the soil and the liner, such as sand or, as a more cost effective means, recycled carpet. As a final insurance against leaking it is imperative to wait until the entire pond is lined with a good overlap and filled with water before trimming it to size.

As I said before, the amount of space required for your pond entirely depends on your preference and, as many experts would say, the size of your pond should be dictated only by your space and budget – the wildlife will grow to fit whatever space you give them!

By Josh Ellison

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