Making a water garden doesn't have to require an engineering degree, a backhoe and lots of space. With a large watertight container and a minimum of six hours of sun, you can nurture a small collection of aquatics in a tiny townhouse garden, on a patio or even on a balcony. Best of all, you'll be able to watch the sunlight sparkle on the surface of your pond in a pot with just a small amount of set-up time.
Putting it together
• Place the empty mini-pond in its intended spot – once filled with water, it will be heavy and awkward to move. (A note to high-rise gardeners: just four litres of water weighs about four kilograms. Check that your balcony can support the weight.) Level container.
• Fill with water and let the container sit for one or two days to allow water to warm to ambient temperature.
• Submerge marginal plants to bottom of container; if necessary, place a brick or two on the bottom to raise potted water plants to correct level. Cover soil surface of each pot with a layer of coarse or pea gravel to keep soil in place.
• Add floating plants.
• Water may turn cloudy from algae growth a couple of weeks after set-up but usually clears after another week or two once the ecosystem of plants, water and sunlight balances.
• When new growth commences, feed with a fertilizer formulated for water plants as directed.
• West Nile virus, transmitted to humans via a bite from an infected mosquito, is an issue in some areas. Disturb the water surface every few days to discourage them from hatching or wash away larvae by periodically overfilling the container. Pots with a 70 litre capacity or more will support a goldfish or two, which eat mosquito larvae. Mosquito dunks, a larvicide containing BTi (Bacillus thuringensis israelensis) are legal in the U.S. but restricted in Canada; check with your provincial Ministry of Agriculture for regulations.
Choose a container that's at least 50 centimetres deep, 60 centimetres wide and holds a minimum of 20 litres; between 50 and 80 litres is ideal. A dark-coloured interior discourages algae and helps disguise the organisms when present. It also gives the illusion of greater depth.
A pond in a pot usually includes floating plants, as well as marginal , or emergent, aquatics in terracotta pots or plastic baskets – the container is submerged, while the plants rise above water level.
• Aim for contrasting textures and varying heights. One tall, spiky plant, such as arrowhead (Sagittaria spp.), dwarf papyrus (Cyperus prolifer) or corkscrew rush (Juncus effusus), with lowergrowing floating plants, such as water hyacinth (Eichhornia crassipes) or water lettuce (Pistia stratiotes), makes a pleasing composition in a small container. If your heart desires a water lily, select a dwarf variety and plant it solo – one specimen will soon cover the surface with its round, flat leaves.
• To control algae, most experts recommend that two-thirds to three-quarters of the water surface be covered by plants.