Tag: Duckweed

As the UK’s drought continues and the Maize for winter feed withers in the fields we need an alterative. Our farmers are already feeding winter food to their livestock. There is an option and it is called Duckweed. That green stuff floating in our ditches and rhynes. It may well provide the alterative to farmers having to cull their livestock or buy in expensive food, if they can find it?

Even if the rain comes now, August 2026, the loss of crops will still create feed shortage through the winter. With wetter warmer winters Duckweed may be the best hope to create the feed the farmers need.

Duckweed production provides: speed, protein, and simplicity.

• Rapid growth — Duckweed can double its biomass in 24–48 hours under optimal conditions. That’s faster than soy, rye grass, alfalfa, or most forage crops.
• High protein content — Depending on species, protein ranges from 25–45%, comparable to soy meal.
• Low resource demand — It grows on shallow water with minimal inputs, making it ideal for marginal land or integrated farm systems.
• Environmental benefits — It absorbs nitrogen and phosphorus, helping clean agricultural run-off.

For UK farmers facing tight margins and environmental regulation, this combination is compelling alongside the cost of deployment on fields too dry to cultivate and plant.

An existing setup

Scalable

It has been done before at scale. One of the most notable large‑scale experiments happened in the 1980s–1990s, when Nestlé supported duckweed cultivation systems in parts of South America, especially in Peru and Colombia.

Here’s what that system looked like:

• Integrated lagoons — Farmers built shallow ponds fed by nutrient‑rich water from livestock or food‑processing waste streams. These can be simple plastic channels laid on the ground
• Continuous harvesting — Duckweed was skimmed daily, dried, and mixed into feed for pigs, poultry, and fish.
• Circular nutrient flow — Wastewater fed the duckweed; duckweed fed the animals; animals produced manure that fed the lagoons.
• Low‑tech, high‑yield — The system required minimal machinery, making it accessible to smallholders.

Results: Farmers reported improved feed efficiency, reduced reliance on imported feed, and cleaner water leaving the farms. Nestlé’s interest was tied to stabilising local supply chains and improving sustainability metrics long before ESG became mainstream.

The UK can borrow heavily from this model — but with modern upgrades. The author has since 2015 been involved in providing project vision and supporting the design of Duckweed schemes in Peru, Jordon, South Sudan , India and other countries with water and food poverty.

Why Duckweed Fits the UK’s Agricultural Landscape

The UK has several structural advantages that make duckweed adoption easier than in many countries:

• Abundant rainfall → consistent water availability for ponds. Our warmer wet winters deliver that water.
• High livestock density → steady nutrient streams for duckweed growth.
• Pressure to reduce soy imports → duckweed offers a domestic alternative.
• Strong research institutions → ideal for optimising strains and systems including Brymore Academy.
• Contractors and farmers able to install the systems quickly and efficiently.
• No Effluent

Duckweed can be integrated into:

• Mixed farms — where nutrient flows are already diverse.
• Dairy farms — using slurry lagoons as growth beds.
• Poultry operations — replacing part of soy meal.
• Aquaculture — especially trout and carp systems.

How do you produce Duckweed?

at the most basic level a channel/ raceway with a water containing nutrients being being forced around a channel with Duckweed growing on the surface. 25% is harvested every day.

The plan shows a typical closed circulating raceway,

Growing medium can be water with added nutrients or effluent containing nutrients that duckweed will clean as part of the duckweed production process.

How do you feed livestock with Duckweed?

• collect it daily,
• a quick wash, using water you have already cleaned.
• press to remove free water and it can be fed wet directly to livestock.
• No complicated machinery and what equipment is needed can be fabricated by a competent local fabricator.

Duckweed will clean water

Duckweed is a fast-growing aquatic plant that naturally purifies water by absorbing excess nutrients, heavy metals, and other pollutants, making it an effective and sustainable water-cleaning solution.

It can clean effluent. Be used as sewage treatment plant because it converts nutrients to high protein biomass.

Mechanisms of Water Purification

Duckweed, belonging to the Lemnaceae family, cleans water primarily through phytoremediation, where it absorbs contaminants directly from the water column. It rapidly takes up nitrogen and phosphorus, which are major contributors to algal blooms and eutrophication, effectively reducing these nutrients by up to 63–65% in wastewater over a few weeks earthecobalance.com+2. The plant also absorbs ammonia, heavy metals, boron, and organic chemicals, helping to protect aquatic life and improve water quality earthecobalance.com+2.

Physical and Ecological Benefits

Duckweed forms dense mats on the water surface, which block sunlight and suppress algae growth, improving water clarity and oxygen levels biologyinsights.com+1. Its small root systems stabilise water, reduce turbulence, and allow suspended solids to settle, further enhancing purification biologyinsights.com. By trapping pollutants in its biomass, duckweed acts like a natural sponge, though regular harvesting is necessary to prevent re-release of stored contaminants earthecobalance.com.

Applications

Duckweed is used in wastewater treatment systems, agricultural ponds, and small-scale fish farms, offering a low-cost, environmentally friendly alternative to chemical treatments. It can remove up to 84% of chemical oxygen demand (COD), 87% of total nitrogen, and 85% of total phosphorus in controlled studies, demonstrating its effectiveness in both municipal and rural settings impress-he.eu. Additionally, harvested duckweed biomass can be repurposed as fertiliser, animal feed, or even human food, adding value to its water-cleaning role earthecobalance.com+1.

Summary

Duckweed is a multifunctional, sustainable solution for water purification. Its rapid growth, nutrient absorption, and pollutant-trapping abilities make it ideal for improving water quality in ponds, rivers, lakes, and wastewater systems, while also providing ecological and economic benefits earthecobalance.com+3.