Getting to grips with the basics of ponds

Simon Harman for Lilies Water Gardens, Peace of Mind at the Hampton Court Flower Show 2004.

1. The pool should be in full sun. Nearly all plants associated with water need direct sunlight to flower, especially lilies.

2. It must be away from trees, particularly if prevailing winds are likely to carry poisonous leaves into the pond. All leaves as they decay in the pool will cause some excessive load to the pool nitrogen cycle, but the leaves of Willow, Elder, Poplars, Laburnums, Yew and Oak are highly toxic anyway.

3. The pool should not be sited where there is too much exposure to the north or prevailing winds.

4. Ponds in boggy waterlogged areas have problems and create problems. It might seem the most suitable area to have a water garden but if you use a liner in your pool there will always be threat of the ground water table pushing up the liner from underneath. Even if you managed to puddle it, and allowed the water draining from the surrounding land to get into it in some clever way, you would always have the danger of fertilisers or other pollutants draining into it as well.

5. For the reason above, the surrounding edge of the pool, be it paving, rock or grass, should be shedding water away from the pool.

6. The size and shape of the pool are important. Is it large enough for the fish population resident at the moment?

The larger a pool or pond is, the steadier is the balance it will maintain. The absolute minimum size is 30sqft with a depth of 18inches. If you are planning on keeping Koi carp, then you need much more.

The shape should be as simple as possible to allow for the natural circulation and movement of water in all areas. Convolutions, clever angles and large indentations can be created from the shoreline ornamentation and decoration: jetties, large marginal planting areas, beaches etc. (See 'The Perfect Pond Recipe Book' or Designing and Creating Water Gardens)

8. Streams running from water recycled from the pool should not be disproportionately large in relation to the pool. Remember that a stream needs an addition of at least 1/2 inch of water added to its surface to get it flowing, and this must come from the pool. Not only this, there is a backlog of water that seems to get hidden in the system. This can mean a considerable loss of water from the pool once the stream is full flood. The marginal plants in particular cannot stand the radical rise and fall in water level.

9. Electrics and electrical items need to be installed to the correct National or European Union standards. Have them installed by, or at least checked by, a fully qualified electrician.