Comments on: Controlling Duckweed & Watermeal – Pond & Lake Q & A

By: kathiethueme

kathiethueme — Mon, 01 Aug 2011 16:49:29 +0000

Duckweed and watermeal are very prolific growers and can cover a pond before you know it. When covering a pond it can look like algae, but up close you can see it’s not. You can try to rake the duckweed and watermeal off the pond’s surface but more will be back within the week. The absolute best way to get rid of watermeal is to use a product called Clipper. Perfect for eliminating persistent floating aquatic weeds like Duckweed and Watermeal, Clipper™ Aquatic Herbicide by Valent® is available in a 5 pound container that is capable of treating ponds up to 5 acres when used in surface applications. Valent® Clipper™ Aquatic Herbicide is formed into quick-dissolve granules that mix effortlessly in water eliminating messy and difficult applications. Valent® Clipper™ can be mixed with water and applied using a chemical sprayer. Valent® Clipper® Aquatic Herbicide can also be used on a wide variety of algae, submerged and floating weeds.

-Missy

By: tomer

tomer — Thu, 14 Jul 2011 06:20:09 +0000

I dont know much about watermeal as it has never really been a huge problem for me, I found some information on this site about duckweed but it has been failing so far. I might have to look into one of these more expensive chemical treatments.

By: kathiethueme

kathiethueme — Tue, 21 Jun 2011 13:30:45 +0000

Hi Mark,

Unfortunetly watermeal is a tough weed to treat. Red Wing or Pond Weed Defense will help remove what you currently see in the pond but won’t be able to keep it from coming back. Aeration and natural bacteria along with Eco-Boost are always helpful. If you are really interested in removing the watermeal we do have a new product called Clipper herbicide. It is more expensive but has thus far produced better results on watermeal then any other treatment.

By: Mark

Mark — Thu, 16 Jun 2011 00:03:09 +0000

I have a pond about one acre surface that now you can hit golf balls off the watermeal and duckweed. Nver lost a fish but it looks terrible. I want to kill the stuff and still be able to eat the fish. My grandson and I like to fish. I dont have a lot of money. How do I kill the stuff and keep it from coming back every year. It seems to die out in October in Georgia

By: kathiethueme

kathiethueme — Mon, 28 Mar 2011 14:24:13 +0000

Hi Scott,

Typically you can add whitecap in early in the season and it is best to begin the process before the weed has overtaken the pond. The bigger concern right now would be fluctuation in water levels. If you receive a lot of spring rainfall or the pond is several feet higher now where you may have runoff to other areas outside of the pond the chemical may become to diluted to work. I would start by adding dye to your pond and monitor the color. If the dye stays in the pond for several weeks and remains dark you should be good to go with the whitecap, however if the dye dilutes quickly there may be to much water movement at this time to have a successful whitecap treatment.

By: scott shadel

scott shadel — Mon, 21 Mar 2011 01:55:48 +0000

I’ve got a duckweed infestation that I believe is
responsible for my fish kill in mid to late June the
last two years. I’ve already got duckweed visible in
parts of the pond and the ice isn’t even all off yet.
The pond is about one acre. Is it too early to try
Whitecap??

By: kathiethueme

kathiethueme — Mon, 26 Apr 2010 18:43:57 +0000

Hi Deb & Mike,

Unfortunetly Watermeal is a very difficult weed to treat. Even Whitecap may not always be able to conquer the entire problem. If you choose to give this a try make sure you purchase enough to treat the entire pond, taking depth into consideration as well. If you have an outlet you will need to close it off for awhile in order to maintain the concentration of product needed to have an affect on the watermeal and always use pond shade. You can also use Pond Weed Defense or RedWing for short term relief if you are not able to close off the outlet. Treatment early on though will definetly give you the best advantage.

By: Deb and Mike

Deb and Mike — Sun, 25 Apr 2010 03:57:31 +0000

We have a 1 1/2 acre pond that we want to treat with Whitecap since watermeal is once again emerging. We want to use Whitecap but understand it isn’t very effective if the pond has an outlet. What are your thoughts? We want to start treatment soon since last year our pond was full of watermeal all summer…HELP!

By: thepondguy

thepondguy — Mon, 14 Sep 2009 16:53:18 +0000

Hi Cindy, Whitecap has the same active ingredient as Sonar, so it will kill both Duckweed and Watermeal. Watermeal is a tougher weed to control, so it will require a higher dosage rate. You can still treat for the weed this year, but it may take 30–90 days to see full results. Early Spring is the best time for the treatment, usually about 2 weeks before you would normally see the weed develop. In either case, just be sure to use the liquid product as the granular does not release fast enough to be effective. When treating by pouring or spraying, you will want to make sure the product gets underneath the floating weed for best results. Duckweed and Watermeal can produce thick mats on the surface and the chemical will just dissolve in the sun before it penetrates the weed (if the chemical is just spraying over the surface of the water). Please let us know if you have any further questions.

By: Cindy Corritore

Cindy Corritore — Mon, 14 Sep 2009 15:17:28 +0000

Along these same lines – we treated our 1.5 acre pond (has small island in middle) for duckweed this spring – used what Sonar recommended – their new product (pour in pond rather than spray). Worked well – then watermeal took over. We have never had that before. At this point it is covering the entire pond except the 20′ spot where our bubbler is for our fish.

My question – I know you recommend WhiteCap – is it too late to apply it since it is starting Fall now? When should be apply it in the Spring. Lastly, will it also kill duckweed or should we use the Sonar product again next Spring?

Thanks much –