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I think I have duckweed or watermeal. How do I know? And how do I treat it? | Ponds & Lakes Q&A

Q: I think I have duckweed or watermeal. How do I know? And how do I treat it?

Q: I think I have duckweed or watermeal. How do I know? And how do I treat it?

Richard – Fishers, IN

A: Duckweed and watermeal are both pond pests. Dense colonies of these prolific plants can completely cover the surface of a lake or fish pond, causing dissolved oxygen depletions and fish kills. These tiny invaders need to be managed before they take over.

But before you control them, you need to get to know them. Let’s meet these troublemakers.

Watermeal

The smallest seed-bearing plants in the world, watermeal is a very tiny (less than 1 millimeter) light green free-floating rootless plant that resembles green cornmeal. They prefer quiet water that’s undisturbed by waves, and they’re often associated with colonies of duckweed and mosquito fern (azzola). Unchecked, these plants can be aggressive invaders.

Duckweed

Duckweed is another very small light green free-floating plant, but unlike watermeal, duckweed has a single root and one to three leaves, or fronds, that measure 1/16- to 1/8-inch long. Like watermeal, duckweed tends to grow in dense colonies in quiet water that’s undisturbed by wave action. Duckweed colonies provide habitat for micro invertebrates, but if it completely covers the surface of a pond for an extended period, it will cause oxygen depletions. As its name implies, duckweed is often gobbled by ducks, which also transport it to other bodies of water but you cannot count them for keeping the weed in control.

Stop the Invasion!

To control these aquatic bad guys, you’ll need a herbicide. Clipper™ and Ultra PondWeed Defense® are both selective plant killers that will attack watermeal and duckweed. They’re a short-term solution for both—be sure to apply as directed.

For long-term control of duckweed, you’ll need something a bit stronger. We recommend Sonar™ A.S.. It’s formulated to control stubborn aquatic weeds all season long. Don’t forget to add pond dye, it protects the Sonar™ A.S. from being quickly degraded by the sun.

Pond Talk: Tell us about your experiences with duckweed and watermeal. Do you have any additional management tips to share?

Deliver Fast & Selective Control Of Weeds - Valent® Clipper™ Aquatic Herbicide

My pond was clean but now it’s starting to turn green. What should I do? | Decorative Ponds & Water Gardens Q & A

Q: My pond was clean but now it’s starting to turn green. What should I do?

Q: My pond was clean but now it’s starting to turn green. What should I do?

Cynthia – Richmond Hill, GA

A: First of all, don’t panic! Let’s begin by taking a look at the three main causes of green water: too many fish, inadequate filtration and not enough plant coverage.

Control Your Fish Population

A booming population of goldfish, koi or other pond fish means an overload of fish waste, and all those excess nutrients actually feed the algae that’s turning your water green. To keep that waste in check, we recommend one 6- to 8-inch fish per 10 square feet of surface area. If you have too many finned friends, consider giving some away.

Provide Adequate Filtration

If your fish are family members and you’re not quite ready to bid them adieu, you’ll need to pump up your filtration with an AllClear™ PLUS filter. Adequate mechanical, biological and ultraviolet filtration will remove the excess waste from the water and help control the prolific green stuff.

Shade the Water

Algae are plants, and plants need sunlight to grow. A third way to control algae is to shade the water with plants like water lilies and water hyacinth. We recommend that you shade 40 to 60 percent of your pond for best results. The plants also provide all-natural biological filtration and make your water garden look great. Not sure what kinds of plants to get? Start with our Aquatic Plant Package, which includes a great selection of cultivars for your pond size.

Give It Time …

Most importantly, try to practice some patience. If you’ve just done a major cleanout, your biological filtration may need some more time to get established and working. Give it a kick-start with some beneficial bacteria like Nature’s Defense. The microorganisms will get to work digesting those dead organics.

If you control your fish population, adequately filter and shade your water, and boost your biological filtration by adding bacteria, your pond will be clear again before long—and you can stop singing those green-water blues.

Pond Talk: If you’ve had to give away some of your fish, how do you find new homes for them?

Three Types Of Filtration, One Powerful Unit - The Pond Guy® AllClear™ PLUS Pressurized Filter

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