Oak floats on the water

Swimming ponds

Advantage of swimming ponds

Swimming ponds have been becoming increasingly popular for a number of years. Your big advantage over classic swimming pools: You do not need any chemical water treatment systems. Instead, the purification of the water is done by the plants - mainly sedges, rushes and various types of reed beds - which grow in a special filter substrate. They absorb nutrients, filter pollutants, instead give off oxygen and thrive in their own area so they don't get in the way of swimming and bathing.

Construction of a swimming pond

The classic swimming pond is divided into a swimming zone and a regeneration zone for the plants. A partition that reaches just below the surface of the water prevents the plants from growing into the pool. At the same time, the planted regeneration zone visually ensures a harmonious transition to the garden. Because, depending on the model, there is little or no technology involved, the swimming pond consumes little energy. Garden lovers like to accept some mud on the pond floor, sometimes cloudy water or even a frog as a swimming partner.

Whether the bathing and planting areas are set up in two separate water basins or an underwater wall divides the pond into two zones: the less technology involved - and the greater the tolerance threshold for algae and animal bathers - the lower the maintenance effort for you Garden owner. What applies to the garden pond, however, also applies to the swimming pond: the larger and deeper the body of water, the longer it can withstand periods of heat without annoying algae formation, as the water does not heat up as quickly.

Minimum size of swimming ponds

The size of the pond is decisive for unadulterated bathing pleasure: 60 square meters of water are the minimum so that self-cleaning works in the shallow bank area. Suspended particles settle, are broken down by microorganisms in the coarse-grained substrate and the nutrients released in the process are reabsorbed by the plants. The regeneration area must have at least 60 percent surface area for an intact nutrient cycle - so only 24 square meters of water remain for swimming in a 60 square meter swimming pond.

Plan a swimming pond

If you are planning a swimming pond, it is advisable to consult a specialist company. Some companies have specialized in swimming ponds and offer integrated systems for self-construction. Experienced do-it-yourselfers who are familiar with dredging and laying pipelines can create the swimming pond themselves. You should pay particular attention to a balanced ratio of swimming water and cleaning plants, the question of the filter systems and the sealing. A hillside property poses a challenge, where a deep cut could cause the ground to slide. This must be prevented by suitable construction measures, such as retaining walls.

Aquatic plants not only bring life to the swimming pond, they also contribute to the purity and health of the water. Garden water lilies and other floating leaf plants, for example, provide valuable shade that reduces algae formation, which is particularly important in midsummer. Some underwater plants also worsen the living conditions of algae by drawing their food - especially nitrate and phosphate - directly from the water.

When choosing the aquatic plants for a swimming pond - especially the water lily varieties - you should consider the different depth zones. Marsh irises, marsh marigolds, rushes, reeds and cattails grow close to the bank. The arrow herb, which aligns its arrow-shaped leaves towards the sun, thrives a little deeper. Then there are floating leaf plants such as water lilies, pond roses and sea churns. Underwater plants and floating plants can be found both in shallow water near the shore and in deep water.

The following plants are suitable for the three depth zones of a swimming pond:

  • Shallow water (0 to 30 centimeters): dwarf cattail (Typha minima), marsh marigold (Caltha palustris), marsh forget-me-not (Myosotis palustris), water lily (Iris pseudacorus), dwarf rush (Juncus ensifolius)
  • Shallow water (30 to 50 centimeters): bulrush (Typha species), green pond rush (Schoenoplectus lacustris), water mint (Mentha aquatica), lesser pond rose (Nuphar pumila)
  • Deep water (50 centimeters): Great pond rose (Nuphar lutea), sea jug (Nymphoides peltata), water lily (Nymphaea species), water knotweed (Polygonum amphibium)

In general, you can plant aquatic plants from April to autumn. The best time, however, is May, as the plants then have a whole summer ahead of them to form roots in the warm water. Bring very little soil into the pond that is as nutrient-poor as possible. A thin layer of sand or fine gravel is recommended on the pond floor. Planting in baskets is particularly practical, but not a must.

The planting around the swimming pond

A backdrop of plants not only makes the swimming pond look natural, but also serves as a privacy screen in the garden. Flowering hedges made of Kolkwitzia or shrub rose, cut hedges and clad fences ensure undisturbed bathing fun. Safety also plays a role here: if the pond can hardly be seen from the outside, it does not tempt children into unauthorized bathing. If possible, place larger deciduous trees to the east of the swimming pond so that the leaves and flowers are not blown into the pond.

In addition to swimming ponds with plants and the classic swimming pool, so-called bio-pools or natural pools are increasingly in demand. Their functional principle: organic substances are not used by pond plants, but rather sifted out of the water with the help of special filters. Since the Bio-Pool does not require a plant zone, it has an area of ‚Äč‚Äčless than 50 square meters - very promising news for terraced house gardeners.

New are additional phosphate filters, the granules of which bind the main algae nutrient, phosphorus. Advantage: You don't need chlorine and the water still remains free of algae. Outwardly, the bio-pools are similar to conventional swimming pools. These, in turn, can be converted into a bio pool relatively easily, as the pool remains. According to the manufacturer, building new bio pools is around ten percent more expensive than building a classic swimming pool, but the operating costs remain lower.

In addition to the classic swimming pond and the bio pool, there are also mixed forms, because the following basically applies: the more powerful the filter system used, the smaller the regeneration zone can be. The suction opening of the filter system should be at the furthest point of the regeneration zone so that the water is circulated thoroughly. A skimmer, a device for sucking off surface water, is ideal here: it guides foreign bodies floating on the surface, such as pollen and leaves, directly into the filter system. The filter chambers themselves, for example, can be hidden very well under flaps in the wooden deck on the bank. The power consumption of the filter system remains relatively low when the inlet and outlet are roughly at the same height as the filter system - this is how the principle of the so-called communicating tubes can be used.

Cost of a swimming pond

The costs for larger swimming ponds per square meter are lower than for smaller ones, but a swimming pond is always an expensive project (between 150 and 500 euros per square meter) that needs to be well thought out, if only because of the complex earthworks. That is why horticultural companies offer swimming pond construction with the garden owners doing their own part, which can save several thousand euros, depending on the size. Models have proven themselves in which the client takes care of the excavation, erects the pool walls himself and later also plants the swimming pond himself - but a specialist company is called in for planning, sealing and technical installations. Depending on the size of the swimming pond and of course the equipment, the construction can still cost 10,000 euros and more.

Our tip: It is best to get several offers for a swimming pond from local companies, compare the prices and ask in advance what costs can be saved through any personal contributions.

Expert tips on everything to do with swimming ponds

Carsten Schmidt is the owner of the company "Teich & Garten" and a member of the gardening, landscaping and sports field construction association. The expert gives further tips on what to look out for when creating a swimming pond.

Mr. Schmidt, can you create a swimming pond yourself?

Basically yes, but you have to be very knowledgeable. That is why I recommend a specialist company for advice and for carrying out the special work. Above all, specialist knowledge requires work steps such as the sealing of the swimming pond, the construction of the pipeline and the construction of the filter. You can easily do the excavation or insert the pond plants yourself.

How much technology is needed?

Nature lovers with plenty of space for a large regeneration zone can do without technology. A skimmer that sucks up superficial dirt such as leaves or pollen is still useful and makes maintenance work easier.

So there is no avoiding the maintenance of the swimming pond?

A minimum of care is important because it prevents too many nutrients from accumulating in the water and sooner or later you get problems with algae. The sludge that settles on the pond floor should be vacuumed off once a year. The aquatic plants also have to be cut back occasionally. You shouldn't be too squeamish about this, because radical pruning is also a form of nutrient deprivation.