Maintaining Indoor Water Features

Maintaining Indoor Water Features

Indoor Water Features

An indoor water feature requires different maintenance techniques to a normal outdoor pool, although the underlying principles are the same. The major problems arise from often uncontrollably high summer temperatures and the difficulty of maintaining winter growth owing to poor light levels.




Everything happens much more quickly in an indoor pool: pests and diseases are likely to appear sooner and be more persistent, while the compost will become more exhausted. As a matter of policy, all indoor aquatic plants should be repotted and provided with fresh compost early each spring. Remove as much of the old compost as possible without disrupting the root-ball. If any plants need dividing, treat them in the same manner as hardy aquatics.

Many submerged aquatics should be replaced each year. The individually planted, non-bunching species, such as vallisneria, are usually alright, but may need occasional thinning. However, bunched plants should be replaced. Remove the young growing shoots, re-bunch them and plant them in fresh compost.

Watch all plants carefully for signs of pests and diseases. Spraying is impossible because chemicals must he kept out of the water, but a systemic insecticide, or the equivalent fungicide for a disease, can be applied directly to the foliage. Wear rubber gloves and use an absorbent cloth to wipe the chemical over as much of the emergent foliage as possible, being careful to avoid causing damage or permitting drips of the chemical to enter the water.

As with all aquatics, dead-heading is vital, but so is the removal of discolouring leaves. It is essential to keep as much decomposing organic matter as possible out of the pool.



An indoor pool offers a great opportunity to enjoy fancy gold fish. All require the same care as the common goldfish, but because the environment will be much more hospitable during the winter, they can be guaranteed to survive. The major hazard is the prospect of oxygen depletion. This may occur if the pond is close to the limits of its capacity, when the fish may be seen mouthing for air at the surface. A gentle spray of cool water from a hosepipe should rectify the situation.

In the long term, however, it will be necessary either to reduce the stocking level or install a pond airpump to increase the oxygen content of the water.

Feeding will be more necessary than outdoors, as the true ecology of the pond, with all its myriad creatures, will not evolve. Feed more regularly and over a longer period, as indoor fish will burn more energy. Give enough food for the fish to feed for ten minutes. After that, remove and discard any that remains afloat. Start feeding early in the year, immediately the fish swim about actively, and continue well into the autumn. During the winter, provide them with a pinch of food every week. If they eat it, continue to do so, but if they ignore it, desist until they appear active and hungry.



If the pool is warm enough to sustain active growth and it is possible to maintain a reasonable day length with high-quality light, the plants will continue growing as if it is summer. A regular manicure, and removal of faded flowers and foliage is all that will be required, along with a careful check for pests and diseases.

If the pool is to become more or less dormant during the winter, a similar maintenance programme to that used outdoors should be implemented. Remove all faded foliage from marginal aquatics and discard it. Cut back any tangled submerged plants, especially those congested with algae, and discard them. Floating plants, like fairy moss, are best removed, a small portion of the healthiest growth being placed in a bowl of pond water with a little soil in the bottom. This should be kept in light, frost-free conditions. Water hyacinth can be overwintered by removing the healthy young plants clustering around the adult and placing them in a deep tray of mud or very wet compost. This should be kept at room temperature.

Tropical waterlilies rarely continue to prosper in winter. Most grow from tubers in a similar fashion to begonias, and they benefit from being stored in controlled conditions. As autumn approaches, remove the containers, cut off the fading foliage and allow the mud to dry out. Do not lift the plants immediately; give them a little time to come to rest naturally. Then separate the tubers and pack them in damp sand.

The rootstocks of nelumbos should also be overwintered in damp sand. Lifting them in the autumn ensures that only a vigorous rootstock is replanted the following year.



Once the winter has passed, check that each waterlily tuber is sound, then pot them individually in pots filled with a good aquatic planting compost. Stand the pots in an aquarium or a bucket of water in a warm light place. Warming the water with an aquarium heater will encourage the tubers to sprout quickly. Within a few days, juvenile underwater leaves will appear, followed a couple of weeks later by the adult floating leaves. At this stage, the waterlilies can be planted in their containers and moved to the pool.

Plant nelumbo rootstocks in fresh aquatic compost in the spring, placing them horizontally in planting baskets. Stand these in a container of water that just covers the surface, and as growth commences, raise the water level. Once the plants are growing vigorously, place them in the pool.

Spring is also the time when floating plants are introduced to the pool. Remove any dead pieces from the over-wintered portions and place the live green material into the pool as soon as the marginal plants break into growth. Carefully remove the water hyacinths from their trays, gently washing the roots free, then float them in the pool. If unbalanced by unnatural root development, carefully cut their roots back with a knife.



1. As autumn arrives, remove waterlily containers, cut back the waterlily foliage and allow the plants to dry out and die back naturally. Do not lift them immediately.

2. Separate out the tubers and spread them out in a tray of damp sand. Be selective and only store those tubers which are strong, vigorous and appear generally healthy.

3. In the spring carefully pot the tubers individually in a good aquatic planting compost. Stand them in water, soaking the compost but submerging them completely once growth is observed.



Indoors, the combination of higher water temperatures, consequent evaporation and topping up with nutrient-laden water adds to the potential for abundant algal growth. Unfortunately, however, most algicides that are recommended for outdoor use will create inhospitable and often toxic conditions in the warm environment of an indoor pool.

Suspended green algae should be controlled by balancing submerged and floating aquatic plants. However, filamentous algae, especially silkweed, creates the greatest problem. This must be removed by hand the moment it is observed. Do not use an algaecide, as apart from the risks of toxicity, the dead silkweed will rapidly decompose and pollute the water.


18. March 2011 by admin
Categories: Gardening Ideas, Water Gardening/Water Features | Tags: | Comments Off on Maintaining Indoor Water Features


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