Pond Logic® PondWeed Defense® Aquatic Herbicide
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  • Details
  • Usage
  • Weeds Treated
  • Reviews
  • Fast Acting Liquid Formula
  • Excellent Spot Treatment
  • No Water Use Restrictions

PondWeed Defense® is a rapid-acting contact herbicide designed to work on many species of aquatic vegetation - works best on mature aquatic weeds. Treated aquatic weeds will generally drop below the surface in as little as 4 - 7 days, with full results in 3 - 4 weeks. In heavily infested areas a second application may be necessary in 10 - 12 weeks. Use PondWeed Defense® in combination with Algae Defense® & Treatment Booster™ PLUS for faster results and algae control.

Usage Information

From dosage rates to product labels, the USAGE tab contains all of the information you need to properly apply your pond care products.

Pond Logic PondWeed Defense 1 Gallon
1 Gallon
Application Liquid
Temperature Restriction None
Square Footage Per Gallon Up to 5,830 Square Feet
Shelf Life 2 Years

Dosage Rates

Treatment Area
PondWeed Defense®
Treatment Booster™ PLUS
2,500 Square Feet 3 Quarts 1 Gallons 4 Ounces
5,000 Square Feet 6 Quarts (1-1/2 Gallons) 2 Gallons 7 Ounces
7,500 Square Feet 9 Quarts (2-1/4 Gallons) 3 Gallons 10 Ounces
10,000 Square Feet 12 Quarts (3 Gallons) 4 Gallons 14 Ounces

How To Apply

Mix the amount of PondWeed Defense® and Treatment Booster™ PLUS (if using) with pond water in a tank sprayer according to label instructions. Spray directly onto target weeds. For deeper water, place the sprayer's tip beneath the water's surface. Over time, the weeds will begin to brown and die. Once completely dead, use a rake, like the Pond Logic® Pond & Beach Rake, to remove dead weeds to prevent an accumulation of dead plant material and muck.

When To Apply

PondWeed Defense® has no temperature restriction, but it should only be applied when weeds are actively growing. Use with Treatment Booster™ PLUS for best results.


  • Do not use in ponds with koi.
  • Do not use in ponds with goldfish.
  • Do not use in ponds with trout, unless carbonate hardness is above 50ppm.


Weeds Treated

The first step towards effectively treating any pond weed is proper identification. Pond Logic® PondWeed Defense® Aquatic Herbicide is recommended for use against each of the weeds listed below. Click on your desired weed for more information and alternate control options.

  • American Pondweed
  • Clasping Leaf Pondweed
  • Curly Leaf Pondweed
  • Duckweed
  • Hydrilla/Elodea
  • Sago Pondweed
  • Southern Naiad
  • Watermeal

What others are saying

4 out of 5

Customer Rating

"Bye Bye Weeds!"Amy of avoca, MI

This product is so easy to apply and gives you great results in no time.I am very pleased with the results.

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1 out of 5

Customer Rating

"Did not work for me"Mark Carter of Keeling, VA

After applying according to the directions; I still had the same problem that I called about. I know that you guys told me that this was what I needed for my problem, but it did not fix my pond. About a month later I received several days of rain and that cleared up my problem. ***Response from The Pond Guy..if the problem was resolved by breaking up in the rain it is possible the "weed" may have been algae or something other then a standard pond weed. If this problem arises again if possible send in a sample of the weed for evalutaion.

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2 out of 5

Customer Rating

"not sure it is working for my pond"randy of indianapolis, IN

Applied this product as soon as it arrived. mixing 3qt to 1 gal plus 4oz of boost. sprayed on duckweed/watermeal and in about 3 days I noticed major changes such as the weeds dying off(yay)after that it seemed to have new growth of possibly the same plants. I applied the second dose to the pond and I am waiting and hoping for good results. **Response from The Pond Guy - Hi Randy - Duckweed and Watermeal are both VERY fast growers and need to be treated as soon as you see them in the pond. PondWeed Defense is a contact herbicide, it only kills what it touches.

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