THE water gardening season is upon us. Planting a garden pool is unlike anything else you might encounter, for, when stocking a pool, a whole new world is being created in which plants, fish and snails depend upon one another.

Submerged aquatic plants replace the oxygen that is lost to respiration. They also compete with slimes, algae and other primitive forms of plant life which turn the water green and unpleasant, starving them out by utilising all the available mineral salts.

Floating aquatics and deep water plants with floating foliage also assist in maintaining a balance. By reducing the light falling directly on to the water, they create intolerable conditions for any algae which tries to dwell beneath.

The marginal plants, although of no great importance in creating a balance, provide the necessary colour to make the pool a continual source of pleasure and delight.

When planning your pool planting, carefully calculate the quantity of each plant necessary to create a balance. At least one third of the surface area of the pool, excluding the marginal shelves, should eventually be covered by floating foliage. This can be a combination of floating plants and deep water aquatics like waterlilies, or waterlilies alone.

Initial stocking with submerged aquatic plants is recommended as one plant or bunch of cuttings to every two sq ft of surface area, while the maximum stocking rate for ornamental fish is 6ins of length, inclusive of tail, to every square foot of surface area, although in practice 2ins to the same surface area is more practical.

Snails of the flat, curled, ramshorn type can be introduced liberally. These graze on filamentous algae like blanketweed and are harmless to plants. Avoid the large pointed whelk-like snails, for these chew the foliage of waterlilies and the emerging shoots of marginal plants.

Waterlilies are usually the first priority when planting a pool. This is hardly surprising, since these wonderful aquatics provide a dazzling display of blossoms from early June until the first autumn frosts and are available in every shape and size and almost any colour.

The planting season for waterlilies and other aquatic plants extends from now until August, the plants being established in baskets of good clean garden soil with just their noses protruding above the surface.

Avoid getting any old leaves or weeds mixed in with the soil as these will decompose and foul the water. Soil from land that has recently been dressed with artificial fertiliser can cause similar problems, most notably the rapid development of a thick algal bloom.

Once a plant is installed in a basket, the compost should be covered with about in of washed pebbles in order to prevent fish from stirring up the soil and dirtying the water. It is also advantageous to remove any adult leaves from waterlilies and similar lily-like aquatics before planting as these provide buoyancy and are capable of lifting the plants right out of the basket.