Gardening Naturally Duckweed Treatment is for controlling duckweed (Lemnaceae) floating on garden ponds. It works through the roots and leaves, limiting the weed’s ability to absorb water and sunlight. The 500ml bottle treats up to 11,250 litres (2,500 gallons) of pond water. Duckweed Control for Garden Ponds Duckweed is a small floating aquatic plant that can quickly form an unsightly covering across pond surfaces. Several species occur, and growth can become particularly noticeable when conditions favour it. This treatment uses two actions to tackle the weed rather than relying on a single method. How Duckweed Pond Treatment Works When added to the water, microscopic substances are absorbed through the duckweed roots and expand, limiting water absorption. The product can also be sprayed neat over the floating leaves. UV blockers then limit the duckweed’s ability to absorb sunlight. This should only be done where the spray can be kept away from other pond plants. Duckweed Treatment Dosage and Coverage Use 10ml per 225 litres (50 gallons) of pond water. The 500ml bottle provides enough product for up to 11,250 litres (2,500 gallons) at the recommended rate. Work out your approximate pond volume before measuring the dose rather than guessing. How to Apply Duckweed Treatment Shake the bottle, then remove the cap that is not on the measuring chamber. Gently squeeze until the required amount reaches the chamber and add it directly to the pond. Where surrounding plants can be avoided, spray neat onto the floating weed for the UV-blocking action. Wind and water movement often push duckweed into thicker patches around pond edges and plants. These areas are worth checking when applying the product. If duckweed is tangled closely amongst other pond plants, spraying may not be suitable. This limits the leaf application, so don’t try to spray through other vegetation just to reach it. A further application can be made after one week if required. Duckweed Treatment FAQs How do I calculate the amount needed for my pond? Estimate the total pond volume and calculate the dose at 10ml for every 225 litres of water. Can I use a stronger dose for heavy duckweed growth? Stick to the stated application rate. Do not increase the concentration simply because there is a heavier covering. When should I check the pond again? Allow a week before deciding whether another application is needed. What if duckweed is growing amongst other pond plants? Take particular care with the spray application. If you cannot target the duckweed without spraying other pond plants, avoid spraying that area.