Renovation & Design

GARDENING: Don't pond panic

Keep your pond or water feature clear of algae with these three treatments

Teresa Lopata/This Pinawa area pond is surrounded by lush greenery, creating a beautiful natural setting.
Teresa Lopata/Water features provide a habitat for visiting wildlife. Incorporating native plant species into your garden design may help to attract more wildlife.
Teresa Lopata/Sunlight glints off the sparkling, algae-free surface of this East Kildonan pond.
Judy Schwartz/Blue flag irises grow naturally in wetter areas like bogs and marshes. This six-year-old clump grows at the edge of a Fort Garry pond. Leave the seed pods on for self-seeding. It takes two to three years for seedlings to bloom.
Teresa Lopata/Even the smallest of ponds, such as this one in a Steinbach area garden which is shaded by a stunning ornamental rhubarb, can suffer from excessive nutrients and algae blooms. Use environmentally friendly solutions such as beneficial bacteria that are safe for birds, pets and humans.
Teresa Lopata/Ponds can be situated in either shade or direct sunlight. It's important to avoid water runoff from entering your pond and upsetting its nutrient balance.

Water features are often the finishing touch in a landscape. Slimy water, though, only detracts from their beauty. Fortunately, there are simple solutions.

Ron Labb©, Shelmerdine Garden Centre's expert on ponds and water features, maintains a pond and multiple water features in his front and back yards.

"One common thing I find with fountains is that people do not keep them running long enough -- only a couple of hours a day", Labbe said. "Turning the pump on and off wears out the pump faster than letting it run .... A fountain that is stopped most of the time allows minerals and sediment to dry to the edges, making it hard to clean. The water becomes stagnant and this allows algae to bloom quicker."

Labbe does not recommend the use of bleach or bromide which can void the warranty on the pump and finish of your fountain.

"Maintain your fountain water clarity longer by having it run 24/7 or at least 12 hours a day. Keep the water level to the max. Once you notice a slime building on the sides or bottom, use a soft brush to remove it. Flush the water and start fresh."

Labbe shares this non-toxic tip for removing stains: "Using a soft brush, clean with a soy-based cleaner or vinegar and water."

Doris McComb, a Charleswood gardener, swears by liquid barley extract for keeping her pond clear. "I add about 10 pump doses first thing in the spring and then a couple each week, especially when the weather is sunny and hot," she said.

Some owners of large ponds even throw in a bale of barley, she added. Miniature bales are available for smaller ponds. "For new pond owners, it will take two to three weeks for a pond to find its proper balance. Be patient the first season," she said.

Today's contributor is Lynne Melvin, owner of Riverdale Supply in Carman (, a wholesale distributor of landscape supplies such as aeration, beneficial bacteria, pond equipment and landscape lighting.

-- Colleen Zacharias



July 13: Birtle's 3rd Annual Gallery in the Garden. Art, classic cars and obelisks in inspiring gardens. 10 a.m. to 4 p.m. Tickets are $30. Email or call 204-773-0670.

July 20: The Manitoba Master Gardener Association's First Annual Garden Tour featuring 12 unique Winnipeg gardens. Tickets are $15. Visit or call 204-269-0444.

July 20: Carman Garden Club's annual garden tour will feature six gardens. Tickets are $15. 1 p.m. to 5 p.m. Registration at 12:30 p.m. at Carman Dufferin Museum, 20 Kelly Hand Drive. Call Kathy at 204-745-2828


Whether you have a small, bubbling water feature, a pond or even a dugout, algae tends to be one of the top issues that plague the water during the summer months. There are solutions, however, that are environmentally safe and very effective.

First, we need to understand what is happening and then we can learn to treat it successfully.

The ultimate goal of a pond, if left alone, is to turn itself into a grassy meadow. A newly constructed pond usually does not have a buildup of debris or naturally growing aquatic plants but, over time, these plants begin to appear.

Organic debris such as leaves, grass and fish waste begin to build up on the bottom of the pond as muck or sludge. As this debris begins to slowly decompose, it releases nutrients into the water. Gases such as methane, hydrogen sulfide and carbon dioxide begin to build up and produce an undesirable smell when disturbed. With the over abundance of nutrients, algae appears and quickly explodes into a mass of green known as an algae bloom.

This is typically when the pond owner begins frantically looking for help.

There are three treatments that, used in combination, can save the day. Let's explore what they are and how they work.

Beneficial bacteria are naturally occurring in the environment. Products such as Bacta Pur and Muck Away have been very successful in finding the perfect selection of bacteria strains that are very effective in consuming nutrients. In water, the bacteria go to work immediately to consume excess nutrients such as nitrates, ammonia and phosphorous, along with organic debris and muck on the bottom of the pond. The bacteria then become food for fish and other invertebrate living in the water. Since the bacteria have consumed the excess nutrients, the algae can no longer survive and dies off. The water clears.

Why do we need to continually add more bacteria? Once the bacteria runs out of nutrients it turns on itself and cannibalizes so the level of bacteria declines quite rapidly in the pond.

There are two types of bacteria, aerobic and anaerobic. Anaerobic bacteria will survive in low-oxygen settings but works slowly at consuming excessive nutrients. Aerobic bacteria, when supplied with dissolved oxygen, works very quickly to consume nutrients, which in turn clears the water. It can multiply every 15 minutes, day or night.

This leads us to the second option for treatment: subsurface aeration using appropriate air diffusers with energy-efficient compressors. These aeration systems add dissolved oxygen to the water, which is like giving "Red Bull" to the beneficial bacteria.

Subsurface aeration also works to eliminate the thermocline of the water. We all know the feeling of swimming in a lake or pond -- the water on top is warm, but down below it's very cold. With subsurface aeration, gases from the bottom of the pond are released into the atmosphere and the dissolved oxygen entering from the surface is then returned to the pond's bottom. The dissolved oxygen then interacts with the aerobic bacteria which breaks down the layer of sludge found at the bottom of the pond. With this turnover of water, the thermocline disappears.

Not all aeration systems are created equal, however. It's important to choose an aeration unit with well-designed diffusers that produce many very tiny bubbles which reach right down to the pond's bottom.

The third treatment is called pond dye, which is like adding sunglasses to a pond. Why would we want to do that? The answer is that beneficial bacteria will grow and multiply 24 hours a day, as it does not require photosynthesis to grow. Other aquatic plants, including algae, require sunlight to thrive. When pond dye is applied to the water it tends to block the sun's rays. The dye typically comes in black or blue. Black tends to look natural and unnoticeable while blue is visible, but both provide the shading effect.

These three treatments are suitable for the smallest of ponds all the way up to small lakes. Even the smallest of water features, such as bubbling rocks, vases, formal falls or patio ponds, can suffer from excessive nutrients and algae blooms.

Beneficial bacteria is very effective for all of these features and is safe for birds, pets and people if they come in contact with the water. With appropriate treatment, you can enjoy a beautiful, clear water feature all season long.

There is also great benefit in planting aquatic plants along the perimeter of a pond or in the stream bed if one exists. It's best to plant bare-root plants right into the gravel of the pond -- they work hard at pulling nutrients out of the water, which is very beneficial.

Water plants create a beautiful natural setting. Water lilies require full sun and need to be placed in an area of the pond where the water is relatively still. But did you know that some of our perennials perform very well in a pond setting? Ribbon Grass, although invasive in the garden, can be planted in a stream bed or along the shallow perimeter of a pond. It looks amazing with its variegated leaves and can be contained in a bog container.

If your pond is in a shadier location, ferns are a great addition to the stream bed, adding a lovely texture that contrasts and softens the rocks in the nearby area. Marsh marigold is also an attractive marginal plant that is native to Manitoba. It's leathery round leaves have a tropical look. The plant produces a vibrant yellow blossom soon after they begin to grow in the spring, which adds a nice pop of color early on.


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