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The world of the water garden

A pond is an attractive and interesting addition to any garden. It is inexpensive and easy to construct and, once established, requires the minimum amount of maintenance. Your pond will add a new dimension to your garden. Not only will it bring light and space to ground level, but the combination of water, vegetation and shelter forms a unique habitat which will attract a great variety of wildlife to your garden - frogs, newts, pond skaters, dragonflies, pond snails, fish, water boatmen.

Before you do any actual digging, you need to consider a few points:

1. your pond should be located in or around the lowest point in your garden
2. a sunny location, preferably south facing, is most conducive to attracting the greatest variety of wildlife
3. the ratio of surface shade to unshaded pool area should be in the region of 6:4
4. do not locate your pond under trees or near over-hanging shrubbery. If this is unavoidable, however, a greater degree of maintenance is required when leaves fall in autumn
5. do not locate your pond too near to your house as a constant movement of people will disturb it's wildlife
6. if you have young, inquisitive children in your household, make sure that your pond is not a potential danger to them. You may need to have it fenced off from the rest of your garden until the children are old enough to exercise caution themselves
7. your pond should have an irregular perimeter as this increases the area of shallow water at the edge of the pond which provides important shelter for wildlife
8. a pond needs a reasonable depth of clear water
   
   BUILDING YOUR POND: LOCATION & LINING METHOD

   The best time of year to begin construction is during October and November. Once you have decided on the pond's location in your garden, the next step is to mark out it's shape by using pegs and string. This can be done any number of times until you are happy. You also need to decide which type of pond lining you are going to opt for. There are 4 different types:
   
   Puddled Clay Linings

   This is the traditional method of lining ponds and involves pounding water and clay together to form an impermeable mass. This lining should be no less than 15cm thick (including the sides of the pond) and covered with a 60cm layer of soil to prevent cracking. The pond should last for approximately 10 years. One important point to remember however, is that it is absolutely essential that the pond not be allowed to dry out otherwise cracks will appear.
   
   Concrete linings

   The most expensive and the most durable method of lining a pond. If applied correctly, it should last a lifetime.
   
   Moulded Fiberglass

   Inexpensive but, unfortunately, very restrictive with regard to the size and shape of the pond. Moulded fiberglass linings are really only suitable for small ponds.
   
   Synthetic Linings

   The ground needs to be prepared with the utmost care before any of these linings can be put in place. The excavated site should be covered with a layer of sand preventing stones puncturing the liner. Once the liner is in place, it may need to be covered with a layer of sieved subsoil to protect it from harmful UP rays. There are four types of synthetic lining:

   PVC sheeting - Quite durable and can be repaired using bostik and rubber patches.

   Nylon-reinforced PVC - Brand names - Flexilene and Wavelock. A strong, durable lining.

   Butyl Rubber - Stronger than PVC linings but not puncture-proof. It is both flexible and durable.

   Polythene Sheeting - Comes in 500 or 1,000 gauge. Inexpensive and, when used as a double layer, quite strong.
   
   DEPTH

   Before digging commences, the following points should be noted:

   • The pond should be at least 60cm deep both to prevent freezing and if you wish to have waterlilies or fish.
   • The sides of the pond should slope gradually towards the centre; usually the deepest part. A saucer shape is ideal.
   • A large pond should be approximately 2 - 3m at it's deepest point.
   • Decide whether you would like to leave a central island for nesting waterfowl in a larger pond.
     
     DIGGING
   • Dig a hole the size and shape of the pond. Keep the turves to one side.
   • Dig a small trench around the pond perimeter if using a liner.
   • Remove any sharp stones etc. from the excavated site.
   • Allow at least an extra 10cm for cushioning below the liner when you dig the hole.

   
   
   LINING

   A fairly accurate way of calculating the amount of liner required:
   
   Maximum Length of pond + Maximum Depth X 2 = Liner Length
   Maximum Width of pond + Maximum Depth X 2 = Liner Width
   
   

   • Make sure that the ground is free of any sharp objects
   • Line the prepared hollow with old carpet, newspapers or a 5cm thick layer of sand or sieved soil
   • Spread the liner over the hollow and bring up to cover the trench
   • Cover the liner with sieved sub soil

   
   
   FILLING

   • Place a piece of old carpet (1m squared) in the centre of your pond and fill slowly, letting the water form your garden hose soak through the carpet.
   • Fill your pond slowly as the weight of the water pulls down the liner.
   • Trim and bury the edges of the liner, possibly with the turves you have already set aside
   • Add a bucketful of natural pond water to provide microscopic life.

   At this stage, your pond should be left undisturbed for a couple of weeks to allow it time to settle down before planting.
   
   PLANTING

   The best time for pond planting is mid-Spring to Summer. One of the keys to having a healthy pond is to include a considerable amount of oxygenating plants. Oxygenating plants should occupy about one quarter of your pond and will help reduce algal problems.

   There are three types of oxygenating plant:

   Submerged:

   These grow entirely underwater thus providing a hiding place for pondlife.

   • Callitriche (Waterstarwort)
   • Ceratophyllum demersum (Hornwort)
   • Fontinalis antipyretica (Willow moss)
   • Myriophyllum verticullatum (Milfoil)

   Floating:

   These plants drift on the pond surface. By providing shade, they starve unwanted algae of light.

   • Hydrocharis morsus-ranae (Frogbit)
   • Lemma minor (Duckweed)
   • Stratiotes aloides (Water soldier)

   Deep Water:

   These plants have their roots on the pond floor and their leaves on the surface.

   • Hottonia palustris (Water violet)
   • Nuphar lutea (Yellow pond lily)
   • Nymphaea alba (White water lily)

   Non-Oxygenating Plants:

   These are oxygen-consuming plants which live in the pond's shallows and in the waterlogged ground surrounding the pond. There are two types:

   Marginal:

   These plants grow in the shallows and provide shelter to amphibians. They should be chosen to flower in succession throughout the summer to attract insects.

   • Caltha palustris (Marsh marigold)
   • Iris pseudocorus (Yellow flag)
   • Menyanthes trifoliata (Bog bean)
   • Myosotis scorpioides (Water forget-me-not)
   • Ranunculus flammula (Lesser spearwort)
   • Veronica beccabunga (Brooklime)

   Bogplants:

   These grow in waterlogged ground and attract bees and butterflies.

   • Ajuga reptans (Bugle)
   • Cardamine pratensis (Lady's smock)
   • Filipendula ulmaria (Meadowsweet)
   • Lychnis flos-cuculi (Ragged robin)

   In a small pond, grow plants in lattice-work planting baskets. This stops them spreading rapidly and makes dividing easier. Try to use native water plants whenever possible.
   
   ANIMAL LIFE

   Animal Wildlife should be introduced to your pond two weeks after planting. The big decision involved is whether to opt for fish or frogs as the two cannot live together harmoniously. Watersnails (Ram's horns or freshwater winkles) are a valuable addition to your pond as they greatly reduce the amount of maintenance required. Snails prevent stagnation by eating the algae which de-oxygenates the water. Other wildlife you could expect to see include pond skaters, water boatmen, dragonflies and a variety of garden birds many of which will arrive naturally as the pond matures.
   
   MAINTENANCE

   The best time of year to tidy up your pond is during the dormant period - late Autumn and Winter. To collect dying foliage, particularly from overhanging trees, place a net over the pond during the Autumn. About every two years, your plants will need to be thinned. Spring is the best time to take out your plants and divide them. If your pond ices-over during winter, simply poke a hole in the ice; never crack it. By building a garden pond, you are creating a wildlife habitat which is constantly changing. Your garden will benefit greatly and so will you as pond maintenance pales in comparison to what needs to be done in the rest of the garden.

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