Types of Water Garden and Pond Ideas
There are four principal types of water garden or garden pool construction for the gardener to choose from: making a pool in concrete; fitting pre-shaped pools made of plastic materials such as Fibreglass; adapting old containers such as tubs, baths and barrels; and lining an excavation with polythene sheeting.
In addition to the typical garden pool, water can be added to the garden via means of a bog garden and if you are lucky enough to have a stream running through your land, even better!
CONCRETE GARDEN POOLS
These are the most popular; because of the flexibility of the material, concrete pools can be any size and shape. If they are properly constructed — they are durable enough to last for many years.
A concrete garden pool need not be the same depth all over. Water-lilies, submerged oxygenators (plants that provide oxygen in the water) and fish all require deep water; but a shallow part at one end or entirely surrounding the deeper portion will provide a home for marginal aquatics. This outer rim will reduce the cost and labour of the excavation and, because of its shallowness, will make it easier to shape the surround, which can be formal or informal as required.
Ensure that the deeper part of the pool is watertight, as the plants and fish that will occupy it are much less tolerant of drought than shallow-water aquatics. It is best, therefore, to make this part of the pool formal in shape, as a square or rectangular tank is easiest to construct. The final shape required can then be worked in the shallow outer rim.
Mark out the deep area with pegs, and excavate the soil to a depth of 2-½ ft. This allows for 6 inches of concrete, 6 inches of soil (or the depth of a basket) and 1-½ ft. of water. Make sure that the base is level and free of loose soil before laying the concrete, which should be spread over the whole floor of the pool in one operation. Roughen the edges for about 6 in. all round, with a trowel or similar tool, to make a key for the new concrete when the sides are constructed.
The sides can be built in a variety of ways. For instance, a brick wall can be built and then covered in concrete. But perhaps the most efficient method is to construct a roofless and bottomless box of stout timber to stand inside the excavation with about 6 in. to spare all round, and then to pack concrete into the space between earth and wood. Build up the necessary depth of cement by working continually round the box; do not complete one side at a time. Take special care to force the material down at the corners. Oiling or soft-soaping the boards beforehand makes it easier to re-move them a few days later when the concrete has set.
The outer rim of the pool is made in the same way, except that it is only necessary to excavate 10 in. of soil — allowing for 4 inches of concrete and 3 inches each of compost and water. Sides 4 inches thick will be strong enough for this part of the pool.
As it is so important that a pool be waterproof, use only top-quality materials—Portland cement, coarse sand, and clean gravel or aggregate of varying sizes between ¾ in. and 3/16 in. They should be mixed in the proportions of one part cement, two parts sand, and three parts clean gravel or aggregate, with sufficient water to make a good, stiff dough.
If mixing concrete seems too laborious a business, it is worth considering the use of ready-mixed concrete.
Before a new pool is stocked, be sure that the concrete is matured. In its fresh, raw state it is exceedingly alkaline and dangerous to many plants and animals. Goldfish are particularly affected; their gills become sore and inflamed and they finally suffocate.
There are three ways of dealing with the problem:
1. By keeping the pool full of water for six months, then emptying and rinsing it out before planting. This is the usual procedure with a pool constructed in the autumn.
2. By painting over the surface with one of the several proprietary insulating substances available from all good DIY or garden centres. Most of these substances also contain a waterproofing material which helps to ensure water-tightness.
3. By neutralizing with acid the alkaline substances which come from the cement.
Any cheap acid such as commercial, syrupy, phosphoric acid does for this purpose. Stir into the water enough to show an acid reaction to litmus paper 24 hours after adding.
PRE-FABRICATED GARDEN POOLS
These are made of Fibreglass, aluminium or plastoglass, and are so light that a child can handle them. The majority have pressed-out depressions of various depths, to provide planting pockets for deep or shallow water aquatics, and they are available in simple square and circular shapes and also in more complicated designs.
To install these pools, it is only necessary to excavate a hole into which they just fit (a template is usually provided with them), check the rim for level, plant, and then fill with water. As they are made only in comparatively small sizes, the depth of water is often insufficient to
prevent deep freezing in winter. This means that the pool has to be protected in bad weather. The edges of these pools can be concealed by turfed, paved or flagged surrounds.
MISCELLANEOUS GARDEN POOL CONTAINERS
Tubs, old baths, stone troughs, coppers and even galvanized tanks can be used for water gardens. Copper is not a suitable receptacle for most livestock, but water-lilies and aquatics grow in it safely.
Old wooden wine or beer casks sawn in half can also be used, free-standing or sunk in the ground. They need thorough cleansing beforehand, and should be kept filled with water or the staves will shrink and the tubs leak. If free-standing casks are to be painted, cover only the outside surfaces.
Most receptacles present a better effect when seen from above, so it is usual to sink tubs. If the rims are well below ground level, pieces of stone and scrambling plants can be put round the edges to mask the outlines. A boggy surrounding area suitable for marsh plants can be made by occasionally flooding the tub.
This is a cheap and simple method of preparing a site for growing aquatics; all that is needed is to excavate the area to the required shape and depth (or depths), line the depression with thick polythene sheeting (500 gauge), fill with water and introduce the plants (in baskets) and fish.
A new type of plastic sheeting, known as Plastolene, is reinforced with Terylene. This expands so that when slowly filled with water it takes up the exact shape of the excavation. It is available in a variety of colours and has greater strength than ordinary plastic.
There are two sources of danger: a stab with a fork or similar sharp tool spells disaster; and if hot sun constantly plays on the material above the water-line, it is liable to become thin and leak when the pool is full. For this reason protect the edges of plastic pools with pieces of rock or by laying soil or paving stones up to the water’s edge; and always keep them full of water.
Many plants like to feel the influence of water without actually growing in it; they cannot stand drought, yet cannot live in stagnant moisture. These are the bog plants, some of which are the most colourful plants in the water garden.
There are several alternative ways of arranging for constant moisture during the active growing season. Firstly, the area may be flooded periodically, which is quite successful if the flood water can be trapped.
But if it runs all over the garden it will be a wasteful nuisance. There is also danger that, during a period of drought, when water is most urgently required, local authorities may enforce water restrictions.
A second method is to place 6 inches of drainage material such as broken crocks, stones or washed clinker over the base of a l ft. deep basin, cover this with a layer of turves laid grass side downward, and then 10 to 12 inches of compost. In this soil bed raised above the level of the neighbouring pool, the plants’ crowns will rest in well-drained soil, but the roots will go down to or feel the influence of the water below.
Often there is no need to carry out any special construction work to grow bog plants; in reasonably moist or heavy soils sufficient moisture is usually present in the ground to take care of their needs. An annual top-dressing with a mulch of well-rotted leaves (in April or early May) will conserve the moisture.
Rock and water are natural partners, and in the garden streams and waterfalls not only bring beauty, but sound and movement as well. A large area of ground is not essential, but the site must, of course, be sloping. At the highest point, water from a hidden tap will trickle slowly into a basin or cavity, to spill over in a waterfall and collect in another basin. Here it spills over again before running, via a stream, to the largest area of water, which is the pool proper. Surprisingly little water is needed to create attractive effects and there are several models of pumps on the market which will return the water so that it is used over and over again.
Remember that constantly moving water is not good for lilies and the more decorative aquatics, so that the source of supply should be turned off at night and in cold weather. Also, the path of the water from the top of the rock garden to the main pool should not be too straight. In Nature, water takes the line of least resistance, finding its way through soft rock and round obstacles in steady descent to the lowest reaches. Study such phenomena in the wild or visit some good rock gardens before embarking on the building of a stream garden.