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The Benefits of Growing Duckweed

Mary is a tilapia farmer in Brazil. Through her articles, she shares insights and tips to make your farm more profitable.

Growing duckweed

Growing duckweed

Duckweed Growth and Benefits

For some, duckweed is a menace. For others, it's a godsend. This plant can reproduce rapidly, and depending on its growing environment, it can double in as little as 16 days.

This makes it either a formidable enemy or a fantastic ally.

Today I would like to highlight the positive side of duckweed and tell you why we have built specially designed ponds to grow it here on our farm in Brazil.

For those of you who don't know what duckweed is, it is a small floating plant that grows on still ponds. It can cover an area rapidly and because of this can cause problems. Now, however, duckweed is being touted as a miracle plant for many reasons.

Duckweed as a Water Filter

Duckweed loves muck. It can clean the water from farms that are rearing cows, hogs, chickens, and other livestock. The runoff created from intensive farming methods can cause an ecological nightmare if left untreated—especially if it leaches down into the water table. Duckweed can clean this water by absorbing the resulting chemicals.

In Palestine where they have limited fresh water, they are looking at using duckweed to clean their water systems. Using this natural, low-cost water treatment is good for the country and the environment; it's a win-win situation.

Our duckweed ponds

Our duckweed ponds

Control of Mosquitoes Using Duckweed

Mosquitoes love shallow still pools of water to lay their eggs in. This is a major problem in many countries, not just developing countries. Duckweed could be the solution in many of these areas.

Because duckweed covers the surface like a thick blanket, it blocks the mosquito from laying eggs. Malaria, yellow fever, dengue fever, chikungunya, and the Zika virus are the five main diseases spread by mosquitoes here in Brazil and other parts of the world.

Stop mosquitoes breeding and you drastically reduce the number of illnesses and deaths attributed to them. According to the World Health Organization (WHO), mosquitoes are endemic in 91 countries and affect 40% of the world's population. Diseases transmitted by mosquitoes are estimated to kill 2.7 million people per year. With numbers like this, looking into cost-effective ways to reduce their breeding areas, puts duckweed as a sensible option in many areas.

Duckweed as a Biofuel

Scientists are working on ways to utilize duckweed as a biofuel. With the rapid reproduction of this plant, it has not only scientists but also environmentalists taking notice.

Other plants are being grown for bio-fuel but none grow with the rapidity of duckweed. Currently, the main bio-fuel crops are

  • Corn (maize)
  • Elephant grass
  • Sugar cane

These take up vast areas of farmland, often in developing countries, which could be used to grow food crops for the local population instead of crops that will be made into biofuel and sold to the westernized developing countries.

The advantage of duckweed is not just its speed of growth but because it grows on water, it frees up the land for farming food crops. Plus with its water purifying properties, it leaves clean water behind.

Duckweed as Tilapia Food

The reason we decided to grow duckweed was to feed our tilapia. My husband and I have a small farm in northern Brazil where we raise tilapia for the local market.

We are growing the duckweed to use as a supplemental feed for the fish. The high protein content makes this an ideal food for them. Although we feed them this astounding plant, this alone will not sustain the fish as a complete food source. We still feed them commercially prepared pellet food every other day as this ensures all the nutritional requirements of the fish are met. Feeding the fish duckweed has reduced our feeding bill by half!

That is a massive saving when you're feeding several thousand fish.

It isn't just fish that eat duckweed though. We have also fed this to our chickens. If started when they are young, they readily accept it.

In some parts of the Far East, it is being sold and consumed by humans as well. We are also now farming shrimp and these are fed duckweed which has been dried and frozen.

The ability to use a naturally occurring plant has opened up an opportunity for small farmers to successfully raise their own fish for sale or consumption. Where before, the cost of feeding them to adult size, would have been cost prohibitive.

How to Build Ponds for Duckweed

For our five ponds, we hired a backhoe and driver. Depending on how many you are wanting to construct, you may be able to do this manually. You will want the water to be no deeper than a foot. We made our ponds 30 m long by 2 m wide (98' x 6.5') and used a plastic liner in them.

Constructing our duckweed ponds

Constructing our duckweed ponds

Choosing a Pond Liner

The quality of pond liners varies. For ours, we needed one that was suitable to be used while underwater and in the sun, and that wouldn't leach anything toxic into the water. Leached toxins can damage the plants and subsequently cause problems with the fish.

In our region of Brazil, the UV light from the sun is in the extreme category. This, coupled with the salt in the air which destroys fabric, plastics, and metals, meant we needed a high-quality liner. Environmental elements need to be taken into account when selecting a liner.

Remember to leave enough for the ends and the sides when you calculate the dimensions. Once you have laid this in your shallow pond, secure it while you fill it with water. We went low-tech and used bricks to hold it down from the constant wind we have here.

Getting Your Duckweed to Grow

Your duckweed pond will require feeding with manure soaked in water to soften. We use a 100-liter plastic trash can for this purpose.

My husband puts the manure in (we use chicken) and then fills the trash can with water to allow it to soften. Then he buckets this mixture into the ponds. Onlookers should stand well back as there will be splashes. In a couple of days, you will have rapid duckweed growth.

If the roots are more than a couple of inches long, you will need more manure. They are trying to stretch out and find nourishment, so the ponds are kept shallow.

Harvesting Duckweed

Harvesting the duckweed is easy. We simply use a swimming pool net on an extendable aluminum pole. This is a quick and efficient way to scoop it out. The weight of the water-laden duckweed can be heavy. I found it beneficial to walk to where I wanted to scoop from, scoop it out and allow the water to drain back into the pond. The further away you are using your net, the heavier the duckweed will feel. Move closer to where you are working from and save your back.

This is also a good way to remove any leaves which may have blown in. If you live where there are trees, it is a good idea to put up a barrier such as chicken wire or plastic fencing to keep as many leaves out as possible.

Always clean your net after using it to prevent any bits of duckweed from dying on the net and causing a blockage.

Inexpensive overflow system

Inexpensive overflow system

Overflow for Ponds

My husband made an overflow system out of a plastic pipe and Coke bottles. We can get downpours that last several hours and deposit an enormous amount of water in a short time. Because duckweed floats, we needed something to allow the water to flow out but not carry the duckweed with it. This is a simple but effective method. Also, be aware that after a heavy rainstorm, you may need to add more manure, as the rainwater will have diluted your ponds.

Wildlife in the Ponds

Many a night, during the mating season, we have high numbers of frogs in the duckweed ponds. We encourage everything here with the exception of cane toads. There are beetles and other aquatic life which have made their way into the ponds on the feet of herons. It is always a good idea to inspect the pond for things living in there, the quality of the water, and the condition of the liner. This can be done when you are harvesting your duckweed.

Cleaning the Pond

If you are using manure from a chicken farm, you may end up with sawdust debris in the bottom of your pond. It is a good idea to drain it occasionally to clean it.

Draining can be done through evaporation, siphoning, or by using a bilge pump. If you have never siphoned off anything, it's simple. Put one end of a hose in your pond and the other end at a lower level. Suck on the end of the hose until water begins to flow out. Remember, you've added a lot of manure to the water, and you don't want to drink that.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

Questions & Answers

Question: I have an aquaponics system with tilapia in IBC tanks. Could I grow the duck weed in the aquaponics tanks of my system or would the weed become a problem?

Answer: The duckweed wouldn't become a problem if you can contain it. You can always drain the water from that portion of your system and remove it.

If you have it where your fish are, they will eat it. Keep it in a separate pond with shallow still water. It has to be in at least partial sun.

Question: Why do you want to harvest duckweed?

Answer: We harvested our duckweed to use as food for our tilapia. We used it as a supplemental feed every other day. This reduced our feeding bill dramatically.

Question: How long does the common duckweed live?

Answer: It's a good question but I can't answer that. I'll explain why. When we were first given ours for our ponds, we were given about a tablespoon of two different types. The man had kept them in a bottle for about a week before arriving at our farm.

When we put them in our ponds, they began reproducing, so I have never kept any back to see how long one plant would survive, they just keep reproducing when in a suitable growing medium.

I do know that even when an area that had duckweed dries out, when it becomes wet again, the duckweed is likely to return.

If you are thinking of ordering online and hoping they arrive in good condition, the supplier generally gives you extra to cover any potential loss. Remember they grow fast.

Question: What time of year can I introduce duckweed, so it doesn’t die off in the cold? I live in St Andrews, Scotland.

Answer: For introducing it, wait until any chance of frost has passed. However, once it is established, it can overwinter and stay green according to the RHS. We have noticed it will still return, the following year even if the area is dry. It goes into the mud and waits to resurface and start reproducing when the rain starts.

Question: I have a pond covered in duckweed and want to sell it. Can you suggest how I can do this?

Answer: You have various options, and some may be better for you than others depending on where you live.

You can sell online on sites such as eBay. There are restrictions such as sending abroad, that is forbidden in many countries.

Sell it as chicken feed to local farmers. For this, it may be better to dry it first.

Sell it to fish farmers or those who are doing aquaponics with fish.

If you have a local pet store that has aquariums, see if they want to buy it to resell.

Question: Do you have a problem with the water in your shallow ponds getting too warm under the sun, especially with black liners? Won't that kill the duckweed? Also, do rainstorms/wind kill the duckweed?

Answer: The answer to both of your questions is no. Remember, in the wild duckweed will be growing in a pond which likely will have a build-up of silt and so will be dark and shallow. With regards to the rainstorm, the problem could be that it would float out of your pond as the water rises. In the photo, you'll see a low cost (virtually free) method of creating an overflow system so the water flows out and the duckweed stays in the pond.

Where we live, it is 87°F (30°C) year-round and we get a UV index of 11 which is in the extreme range. We also have a constant wind for several months. What I would suggest is find a duckweed that grows local to you, and then you'll know that it will survive in your conditions.

Question: Do you circulate the water in the ponds for oxygenation? If yes, how?

Answer: No, there is no oxygenation of the water. Duckweed grows successfully in the wild on ponds and there is no added aeration.

Question: I want to DIY a small duckweed pond for my commercial fish farm, how can we design the overflow drainage system using cola bottles?

Answer: In the image in the article, you can see how to do this. We used two per pond shown in the photo. Cut the bottom off the cola bottle and a hole in the side. The hole in the side is connected to a drainage pipe. Thus the water flows out but the duckweed stays in.

Question: Is duckweed good for my outdoor guppy and guppy fry ponds?

Answer: Try a small amount and see if they eat it. I believe they will. If they don't, remove as much as you can because it will spread.

Question: How do you feed the duckweed to your tilapia?

Answer: We use a swimming pool net that is on an extendable aluminum pole. As we scoop it out we let the majority of the water drain out of the net. We then fill a plastic box, it's about 33 liters capacity. We then take this to our boat and row out to the cages. We put in about the size of a soccer ball (football) of duckweed in each cage.

If there is still duckweed left over the next day, when we use our pellet feed, we reduce the amount we give them.

Question: Do cows eat duckweed?

Answer: Yes they can, although only as supplemental feeding. It can be dried or green. It is currently being suggested as a potential high protein resource for many animals of which cows are one.

Question: Do frogs like or dislike duckweed?

Answer: In my experience, they like it. Not to eat, as they are carnivores. They will sit in the water waiting for insect to arrive. The duckweed is a great cover for them to hide beneath.

Question: This was helpful. I still have a few questions. Did you grow duckweed without the seeds? You mention that you put waste in the pond, what kind of waste? You also said manure too, didn’t this make the pond smell?

Answer: We started off with perhaps two tablespoons of duckweed that were sourced from local ponds. We used chicken poop that we had purchased from a local man who bought it from a factory farm. The smell only occurred when we were mixing it in a trash can to add to our ponds. The ponds never smelled of manure or stagnant.

The waste I was referring to was the runoff from some farms. Cattle, pigs, chickens all produce a lot of waste. The use of duckweed can help minimize the effect of such waste. As I said, we only used chicken manure that we purchased.

© 2012 Mary Wickison


Mary Wickison (author) from USA on July 26, 2020:

Hi Jim,

Depending on your set up, you could try this. We didn't use this approach for a few different reasons.

Where we live is windy and it would all blow to one side. What happens is it goes on the bank and dies.

We had most of our tilapia in cages in our lake. Although our lakes were aerated, we didn't want duckweed to take over removing the light and oxygen for the fish.

We felt we could control the amount that was being eaten and change it if necessary.

Jim Mader on July 26, 2020:

I'm wondering if the tilapia will eat the weed without having to harvest it?

Mary Wickison (author) from USA on October 27, 2019:

Thank you for your kind words Gil, I'm glad you enjoyed it.

Gil Romero on October 26, 2019:

You are a delight and inspiration Mary and thank you so very much for all of the great, to the point and useful... (and too rare!) information!

I wish you and your lucky husband every happyness, and continued success...and best of health.

Sincerely from the wonderous Yucatan of Mexico

Gil Romero

Mary Wickison (author) from USA on March 26, 2019:

I have not raised catfish so had to do some research. Although we think of catfish as a bottom feeder, they do take food from the surface. Because they are omnivores, I would say, try duckweed and see if works.

Because the duckweed can often be sourced for free, you have nothing to lose extra some of your time.

Something we did notice with the tilapia, if they aren't accustomed to it, it will take a few times before they realize its food.

The earlier you introduce duckweed to the fish, the more money you can save on food and the more likely they are to accept it.

El-Rasheed on March 26, 2019:

Do Catfish eat Duckweed as well?

Mary Wickison (author) from USA on November 11, 2018:

Hi Paul, I'm not sure if that is a question or a statement. With regards to drinking water, be careful.

I would suggest you have your water tested to ensure it is safe for consumption.

Duckweed may be part of a water filtration system but where the health of you and your family are concerned, you can't be too careful.

Here on our farm we drink well water. Our wells are rather shallow and we are on sand and a long way from our cesspits. I still pass our water through a charcoal and pumice filter before drinking. Other people here also boil their water before drinking.

There are home test kits or your city council should be able to direct you to a water testing center.

paul on November 11, 2018:

We in the Us could use duckweed to clean our drinking water

Mary Wickison (author) from USA on October 31, 2018:

Hi Enoch,

Regarding feeding duckweed to the chickens, my adult ones weren't that eager. They would eat it but they weren't going crazy like they do for maggots. If chicks were accustom to it from an early age, they would be more willing. That said, our chickens were free range and had a wide variety of green vegetation to choose from.

I didn't try moringa but I can see no reason not to try it. If the fish don't like it, it will be left floating. A friend here in Brazil has a couple trees and feeds the leaves to her dogs, in a vegetable mixture she combines with raw meat. So carnivores will eat it. Duckweed can be a supplement for the tilapia but if you are growing them commercially, then you will need to give them commercial pellet food.

Enoch on October 31, 2018:

Hi Mary

I want to know if you had fed it to chickens before and what was the results?

And also if you have tried mixing duckweed and moringa in feeding the tilapia

Mary Wickison (author) from USA on November 22, 2017:

Hi Oded,

Your question has several factors. In our area, people will sell at 450 grams. However, if you are selling to a company who comes in and buys all your fish, you will be paid more per kilo for heavier fish. The reason some places sell early is tilapia will begin breeding and when this happens you have problems. You will end up with too many fish with stunted growth. Locally there is a man who rears his to 2 kilos but he has a very small manageable enclosure about the size of a small swimming pool. When the fish begin to breed, that is all they think about and the weight gain can be slow.

We started with 30g and 50g tilapia. The reason we decided on those sizes was due to the size of netting on our cages. If we had bought the fish too small, they would have passed through the netting and into the lake.

Regarding the amount of duckweed. We didn't weigh it. We used a swimming pool net to take it out of our ponds and filled up a large plastic box. We put this onto our kayak and rowed out to the cages. We put in more than we thought they'd eat. Remember, this is free food so you can be generous. If you compare it to the size of a football (soccer) we used two of these for one cage. Our cages were 2m x 2m. Also, we had larger cages 3m x 2m which had more. Although those cages could take 600 and 900 fish respectively, we had about half that amount.

We judged the duckweed amount by how much was left after they finished eating it. If there was some left, the next time we gave them less.

Tilapia should gain weight at about 3 grams per day with commercial feed. If using duckweed on alternate days or if you implement delayed feeding, the weight gain will be slightly less. However, by using duckweed or a delayed feeding program, your feed bill will be drastically reduced.

Thanks for your questions, I hope this helps.

Oded on November 22, 2017:

Hi Mary.

Thank you for the information.

You said that you feed your fish one day comercial feed and other day on duckweed.

I would like to know how long it take to raise you fish to comercial wegiht?

What is your fish comercial wegiht?

And what is your fish inicial wegiht?

What is the wegiht of duckweed the you feeding your fishes?

Thanks you, this info can be very helpful to me

Mary Wickison (author) from USA on November 14, 2017:

Hi Oded,

I have just had a look at an article about it, and it sounds like a positive way to go. We haven't used that system but I can see the benefit in doing so.

Using duckweed every other day helps offset some of the problems associated with the ammonium buildup because it is a natural product.

One tilapia farm in our area harvest their fish at 4 or 5 months, then they drain their shallow ponds and scrape the clay bottom to remove a buildup of excrement. They work with a series of ponds so they can produce a continual supply for the local market.

Thanks for bringing that method to my attention.

Oded on November 13, 2017:

Dear Mary,

Thanks for your respond.

I'm searching for information about feeding tilapia with duckweed in Biofloc Technolgy grow up systems.

Do you experience with that.

Thanks again


Mary Wickison (author) from USA on November 13, 2017:

Hi Oded,

We have raised our tilapia in three ways, all which have their plus sides and negatives. We use free swimming in our lakes, in cages and also in tanks.

I have written several articles about tilapia farming. If you go to my profile on Hubpages,you will find them. Owlcation is part of the Hubpage network of sites.

Thanks for your question.

Oded on November 13, 2017:

Hello Mary,

Thank you for sherring the information.

I would like to know which growin technic you used to grow up your tilapia fishes?

Mary Wickison (author) from USA on October 30, 2017:

Hi Adrian,

Sometimes the answer has always been there, especially in nature. I'm glad you found the information useful.

Adrian Boyce on October 30, 2017:

Thanks for sharing your knowledge. Points me in a whole new direction.

Mary Wickison (author) from USA on October 13, 2017:

Hi Johannes,

We had the Nile tilapia.Here in Brazil, it is the most common for fish farming because it grows so quickly.

To ensure the fish get enough nutrients, we fed one day duckweed and the next day a commercial pellet fish food.

Tilapia will grow 3 grams a day with only commercial fish food.

Using duckweed will reduce this rapid weigh gain by about 10 %. If your growing season allows it, we found using the duckweed to be very beneficial as it reduced our feed bill by half.

Thanks for reading and your question.

Johannes on October 13, 2017:

Hi Mary,

What type of Tilapia do you have? Do they only eat duckweed?

Mary Wickison (author) from USA on September 05, 2017:

Hi Abel,

I am glad you liked it. I think that is one of the benefits of the internet, sharing knowledge with each other.

Although our duckweed ponds were quite large, the idea could be scaled down for a smaller venture.

However, duckweed is easily spread from one pond to another. As birds fly off it sticks to their feet and they unknowingly carry it to their next destination.

In some places, it is considered an invasive species and people want to eradicate it.

However, if you have an entrepreneurial streak in you, you can bag it up and sell it. People sell it on Ebay!

Thanks for reading and your kind words.

Mary Wickison (author) from USA on September 05, 2017:

Hi Taylar,

I wrote this article to share my experience of using duckweed. At the time I wrote it we were farming tilapia and built our duckweed ponds as a way of saving money on the food.

We had 10,000 tilapia and they ate a lot. Plus the bigger they got, the more they ate! Growing duckweed allowed us to cut our food bill in half! We would feed our fish commercial pellet food on one day and then the next day we would give them duckweed.

Not only did we save money by feeding them duckweed every other day, we think the fish would taste better with a diet which is more natural.

I wanted to show people that it wasn't that complicated to build ponds to grow duckweed in for various uses around a farm.

Thanks for your question.

Mary Wickison (author) from USA on September 05, 2017:

Now Keegan, if I didn't know better I would think you didn't read my article. I'm just joking with you I am sure you did. Right?

Duckweed is a small floating plant which grows on ponds, and lakes. Many people don't like this plant because it can overtake a body of water. However, like so many things we are just beginning to see the benefit of using this plant. It can double its size in 2 days.

Where I live, in Brazil, there is a lot of bio-fuel used. So for example when you go to a gas station, there is a pump for normal gas, diesel and also alcohol which is a bio-fuel.

The problem many people have with bio-fuels is the crops they grow to make them are land based plants. This land could be used to grow food crops instead of those for bio-fuel. That is one reason why duckweed has people taking notice, it is grown on the water and frees up land for other uses.

Mary Wickison (author) from USA on September 05, 2017:

Hi Joshua,

I'm glad you enjoyed it. You're at the age where you can make a positive difference in the health of the planet. I think duckweed and other renewable sources of water based plant material will have a far greater role to play in the future.

Thanks for your comment, and good luck in your studies.

Mary Wickison (author) from USA on September 05, 2017:

Hi Felipe,

I think it is an excellent topic to cover. I see from your ip address you are in Nebraska, do you see much duckweed up there?

Abel Flores on September 05, 2017:

This is probably the best site I can find that talks about Duckweed.

Mary Wickison (author) from USA on September 05, 2017:

Hi Campbell,

Algae can be a problem as we had it in our lakes.

However, we never had it in our duckweed ponds. If you have shallow ponds where you are growing duckweed, I would suggest allowing the water to evaporate or empty them. Clean the ponds and then start again with the duckweed. Once the duckweed takes over, I would think the algae would die off as duckweed is like a blanket, smothering everything else.

Both duckweed and algae like a nutrient rich environment and it is really a matter of controlling one and allowing the other to grow.

For our algae problem in our lake, we decided to fill in two of our lakes after removing as many fish as possible. Another lake we had a mechanical digger scrape the bottom. The nutrient rich sand, which consisted of fish waste and algae, is now fertilizing our coconut trees.

It was an expensive solution but as we saw it, our only one as we were facing a drought at the time.

If you drain your duckweed ponds, just remember to keeps some plants back to start again.

Thanks for your question and good luck.

Joshua Zeledon on September 05, 2017:

Hi Mary Wickison, we are studying this at school and i think that this is a great article to learn about Duckweed, Thanks!

Mary Wickison (author) from USA on July 05, 2017:

Hi Trevor,

I wasn't familiar with the catfish you mentioned so I did a bit of research. According to what I have read, the species can have up to 20% of plant-based food without causing any health issues for the fish.

I would say duckweed could be an ideal way to help feed your catfish and reduce feeding costs.

Let me know how you get on.

Trevor O on July 05, 2017:

Hello Mary Wickison thanks for this information I just came across ur site and am a farmer from Nigeria. How will be to grow duckweed in my concrete ponds?? And I raise Africa cat fish Clarias gariepinus can I use duckweed for them too?? Waiting for ur reply thanks..

Mary Wickison (author) from USA on April 30, 2017:

Hi Barry,

More manure should get your duckweed growing again. Where we live in Brazil, our temperature is almost a constant year round so I don't have first-hand knowledge about the effect of temperature on the speed of growth of duckweed.

Keep me posted as I'm sure other readers would like to know as well.

Thanks for stopping by. on April 30, 2017:

Very nice reading and gives me things to try as my duck weed has stopped increasing with this cooler weather (20°C) here in Malawi.

There was a similar plant moved in but have removed it by hand but still the quick growth has not returned.

Will replace water and now premix quail manure before adding to the pool.

Man, I just found these super comments below which is great.

Stay well, Barry

Mary Wickison (author) from USA on April 05, 2017:

Hi Wimpie,

Your tilapia set up sounds well thought out. Regarding your duckweed ponds, the amount of duckweed they will produce will be dependent on the amount of fertilizer (or in your case tilapia waste).

You may find yourself in a situation where you will have to choose ponds for water treatment and others for growing the duckweed for food. For the duckweed to grow well and fast (less than 2 days) the water needs to have a hefty amount of manure. When the level is correct, you'll see a sudden growth spurt and the roots will be short. If you don't see this growth and your duckweed has long roots, more fertilizer is needed.

Perhaps using your lagoons in stages, half for feeding and half for cleaning the water.

We were feeding 10,000 tilapia using 5 ponds and that provided more than enough. We weren't recycling our water though.

For cleaning the water, water hyacinths are an excellent plant and can then be used as green matter in a garden.

As for the method of feeding, I used a fine mesh net on an aluminum pole. This went into a plastic box and straight into our cages of fish. Because we had our duckweed growing year round, there was never a reason to dry it.

Good luck

Wimpie Bouwer on April 05, 2017:

Hi Mary,

Thank you so much for sharing all your info.

I live in a small country called Swaziland in the southern part of Africa.

I am planing to start a tilapia production project in Swaziland to supply our local market. The main challenge is the cost of commercially produced feed, it is financial impossible to produce tilapia on commercial feed alone and still compete with the price of imported frozen tilapia, hence why i started looking for an alternative feed source and came across your blog.

Just a bit of background - The system that was designed for us is supposed to produce 4 tonnes of tilapia /month, year round. It consists of 2 x greenhouse tunnels housing different tank sizes with a total volume of 154000 Lt /recirculating system. Each tunnel system has its own bio-filter and solid removal filters. The solid removal filters are meant to be washed on a daily basis and this waste water collects in 11 x (20m x 2.5m x 0.3m) duckweed lagoons for further filtration to be later returned as clean water to the recirculating systems.

My question is thus, would the 11 duckweed lagoons be sufficient to supply 50% supplementary feed to the total system or would i need to add more lagoons?

Also do you dry your duckweed first or do you feed it as is to your tilapia?

Looking forward to your response.

Kind regards,


Mary Wickison (author) from USA on January 02, 2017:

Hi Bucky,

Your project sounds very interesting and creative. What do you plant to do with these creations? I imagine there is a market for this as I have recently read about a company which uses leaves to form disposable eating plates. These can be thrown away without any problem to the environment.

Regarding the relationship of the plants in the pond, yes, everything in that pond will be interconnected. We may not understand the relationship between the floating plants and those which are rooted but they will all be playing a role in the health of that pond.

There is a wonderful series of videos on YouTube called the Natural Farmer in which he speaks about the various roles of plants. Although he is referring to land based ones, the same would hold true for those in the water.

For example, if you took man out of the equation, Mother Nature knows what to do to make the soil (or water) healthy and those plants are the ones which thrive. These will change over time as the needs of the soil (or water) changes .

I am pleased you enjoyed the article and I thank you for your comment.

Bucky McMahon on December 21, 2016:

I enjoyed your article, and congratulate you on your green lifestyle. I live on a suburban pond which can sometimes be overwhelmed by duckweed. I began scooping out some quantities hoping to avoid a monoculture situation. Then I thought I ought to use the scoopings for mulch/fertilizer for the herb garden. Messing around with it, I became fascinated by its texture. Now I dry several pounds at a time on trays and mix it with water soluable glue to make a kind of felt, which I then apply to armatures to make duckweed sculptures. They are very green, as you can imagine, and initially smell rather like a wet dog (but that fades, fortunately). I've branched out lately and began harvesting some of the plants that grow from the bottom up, which are much more fibrous. Is there some symbiosis with the surface and bottom-muck dwelling plants?

Mary Wickison (author) from USA on September 06, 2016:


Pelo que tenho pesquisado, os níveis de proteína são os mesmos. Se usarmos feijão como um exemplo, que retêm os seus níveis de proteína. Eu acredito que isso seja verdade com lentilha de água.

Mary Wickison (author) from USA on May 18, 2016:

Hi Lee,

Thank you for that link it is very interesting and will be beneficial to the readers wanting more information.

Duckweed has many uses such as bio-fuels, human and animal food and as a water cleaner.

Now, when all the world is concerned about mosquitoes and the possibility for them to transmit the Zika virus, perhaps the time is right for city councils to take a fresh look at using this natural deterrent in lieu of spraying chemicals. Or at least to use in conjunction with spraying. So often the answers to many problems, are right under our noses.

Thanks for reading and that link.

Lee Sutter on May 18, 2016:

Thank you. This is the only site I could find that talks about duckweed to control mosquitoes. I've noticed for many years that I never have mosquito larva in the half wine cask containing my small goldfish, where I once added a teaspoon of duckweed from a local waterway near a California coastal estuary. I truly believe this tiny plant can solve many of the major man-made problems on our planet. Here is a very encouraging report from Feb. 2014, the Joint Genome Institute (JGI) of the United States Department of Energy

Mary Wickison (author) from USA on July 19, 2015:

Hi Deb,

It is an amazing plant. We are now using it as a fertilizer on our 400 young coconut trees.

My husband is the photographer in the family and loves photographing the birds, and snakes here. Although we have had snakes in our lakes, never a water moccasin (thank goodness).

Thank you for your visit.

Deb Hirt from Stillwater, OK on July 19, 2015:

I'm impressed. I always wanted to know more about duckweed. We get a little on Boomer Lake, but it usually doesn't grow. We had a lot of rain over the spring and last month, so it helped it grow, I am assuming. I have seen other ponds and swamps, in the deeper South, where it grows like wildfire. As a matter of fact, I got a few shots of water moccasins in a swamp in a NWR covered with the stuff. Thanks for the great info.

Mary Wickison (author) from USA on May 20, 2015:

You're very welcome, I am pleased you enjoyed it.

hi on May 20, 2015:

thanks this is very cool

Mary Wickison (author) from USA on March 20, 2015:

Hi Poetryman,

Normally when I try to recycle trash, I end up with ...different trash. Duckweed however is different.

I will be watching the news for when you do find a solution to save the world. I will say, "I knew him before he became famous."

Thanks for reading and the vote.

Mary Wickison (author) from USA on March 19, 2015:

Hi Patricia,

Thank you for your kind words, vote and sharing. I hope you are having a wonderful day up there in Florida.

poetryman6969 on March 19, 2015:

I hope that one day soon we will find a use for every seemingly useless thing. Politicians, lawyers, reality television, duckweed, kudzu, acorns, fire ants. One of my secret plans to save the entire world in spite of itself is take ALL of our trash and turn it into treasure. Not some make work, feel, good, paperwork shuffle but a real industry that turns trash into Bill Gates level billions.

Duckweed fills the bill. Voted up.

My secondary plan to save the world involves eating zombies. But we would have to find some zombies first.

Patricia Scott from North Central Florida on March 19, 2015:

This is quite helpful information for someone who needs this kind of plant. I am going to be living where I cannot have something like this. Maybe one day when I have a large area I will create a duckweed pond Great instructions.

Voted up++++ and shared

Angels are on the way to you this afternoon ps

Mary Wickison (author) from USA on May 23, 2014:

We used it specifically for our fish to eat. However it has so many uses. In areas where mosquitoes are a problem at certain times of the year, it is beneficial to have this.

Thanks for the votes and sharing.

Shyron E Shenko from Texas on May 23, 2014:

I had not heard of this before, this is fascinating. I like the idea that it can be used as a preventative for mosquitoes, though it would seem it that if it prevents mosquitoes from laying their eggs, it would prevent oxygen from getting into the water.

Voted up UAI, and sharing

Blessings to you my friend


Mary Wickison (author) from USA on October 09, 2013:

Yes it is simple, remember shallow still water is best. If the roots are long, there isn't enough food for it to grow. They like mucky water with fertilizer in it.

Good luck with it.

Power Ball Pythons from Mobile, AL on October 09, 2013:

I finally got some duckweed growing regularly in my fish tank! Now to get it growing enough that I can use it to supplement food for my gold fish. It was all a matter of getting enough circulation to keep the tank clean and having the water be still enough that the duckweed would survive. What I did was have hornwort floating on top, and that's what prevented the duckweed from getting sucked in the filter. I want to try growing it outdoors next. I heard it is very simple.

Mary Wickison (author) from USA on October 06, 2013:

Hi Moonlake,

I enjoy looking at it also. Thank you for your vote and sharing.

moonlake from America on October 06, 2013:

I love the way duckweed looks on a pond. Goldfish like to eat it. Voted up and shared.

Donna Campbell Smith from Central North Carolina on June 03, 2013:

Thanks for the info. Glad we don't have those critters here. Got plenty of folks dumb enough to lick them though!

Mary Wickison (author) from USA on June 03, 2013:

Hi Donna,

The cane toad produces venom through its skin. Nothing, that I know of, will eat them if they do they will die from the poison or become very ill. Here they are in plague numbers. Australia too has a horrendous problem with them. That said some people lick them to get high. It produces hallucinations.

Donna Campbell Smith from Central North Carolina on June 03, 2013:

Very interesting Hub. I have a question - what is a cane toad and why do you not want them in the pond?

Mary Wickison (author) from USA on April 03, 2013:

Hi Letitia,

Glad you found it useful. Thanks for stopping by.

Mary Wickison (author) from USA on April 03, 2013:

Thanks Laura.

Mary Wickison (author) from USA on April 03, 2013:

Hi Jrueff,

Yes, it may well be all over the place. If you can't find it, it is cheap to buy off Ebay. There is a link to it in the page.

Good luck to you and your 'mini homestead'.

Joshua Rueff from Kansas City on April 03, 2013:

Wow, now I'm going to have to introduce duckweed to my mini homestead - this may be a dumb question, but where do I find the duckweed to get started?

I'm guessing it's probably all over the place and I just haven't seen it around, but I'm not sure.

Mary Wickison (author) from USA on November 01, 2012:

I couldn't agree more. If you can't beat them, eat them.

Power Ball Pythons from Mobile, AL on November 01, 2012:

No problem. I really enjoyed your hub. It amazes me that people always complain about prolific plants like duckweed, water hyacinth, dandelions, etc., as enemy weeds when all I see are prolific food producers. It's just a matter of educating yourself and finding a way to use the plant in a productive way.

Mary Wickison (author) from USA on November 01, 2012:

Hello Laura,

I find it amazing how fast that plant can grow. It makes you realize just how productive Mother Nature can be if we give her the chance. Thanks for stopping by.

Power Ball Pythons from Mobile, AL on November 01, 2012:

I grow duckweed to feed the fish in my pond too! Great article. :)

LetitiaFT from Paris via California on June 30, 2012:

I guess I got the tilapia backward. Thanks for clearing that up (no pun intended). I didn't realize the young fish ate algae. Your explanation helps me to understand why it's considered so important for developping economies. Thanks!

Mary Wickison (author) from USA on June 29, 2012:

Hello Letitia,

I am not sure what you mean about the tilapia making the water muddy. They do make depressions in the sand and also they can survive in very low water. Here on our farm we have sand at that base of our lakes. Our lakes are governed by the water table and rise and fall as the rains come and go. Tilapia do clean algae out of the water and in some states in America, municipalities are using them to help clean the water. Young tilapia can survive by eating algae and this is one way tilapia farmers save on the food bill.

Our duckweed is grown in separate shallow ponds and scooped out to feed the fish. If left to grow uncontrolled, it will quickly spread.

Thanks for leaving a comment.

LetitiaFT from Paris via California on June 29, 2012:

Oh gawd, those no-see-ums. We had them in French Guiana when I worked there on sea turtles. There they're called nya-nyas, short for rien-rien or nothing-nothings. Nasty little buggers. But here in Paris near the Seine we have mosquitoes, amazingly enough. I wish I could grow duckweed in my potted plants!

Your article is fascinating. I've always loved duckweed for its aesthetic qualities, but I had no idea of its other uses. I seem to recall that Talapia can muddy clear water (though not as much as carp). Is that so and do you grow duckweed directly on their ponds to help clean them?

Mary Wickison (author) from USA on June 16, 2012:

Hi Teaches12345,

When I was in Florida, it wasn't so much the mosquitoes as those horrible no-see-ums! We have a similar one down here in Brazil.

Ah tropical life!

Thanks for the compliment.

Dianna Mendez on June 16, 2012:

You did an awesome job on covering this topic and made it so interesting to read. I have learned much. Anything that gets rid of mosquitoes is tops on my list. Too bad I can't grow it in m pool.

Mary Wickison (author) from USA on June 16, 2012:

This is an interesting point. One night my husband armed with a flashlight, called me outside. We went to the duckweed ponds and there were frogs, croaking, there necks billowing out with each croak. They were spawning in there and the next morning we had foam. The frogs have come and gone and will return to spawn again.

The problem we have here are cane toads. (I must write a hub about them). They are a problem here as they are in Australia. They excrete a poison that kills anything that predates them.

We do everything we can to encourage frogs to stay in our garden. Anything that eats bugs that might bite me, can stay.

Glad you like the article.

Thanks for the comment.

rbm on June 16, 2012:

Fascinating article! I had no idea duckweed grows so fast. We have a little pond in our garden where we keep tadpoles right now, and unfortunately the mosquito larvae love it too, been scooping them out periodically. I am now thinking that duckweed would work very well here, and the tadpoles would probably be pretty happy with it too, right?

Mary Wickison (author) from USA on June 15, 2012:

Hello Bright Meadow,

I am glad you enjoyed it. I plan to write more about various plants here. Sometimes it is hard to decipher what is folklore and what is fact here. My neighbor swears his mother-in-law can cure fever by putting a root under the bed of the feverish person.

Thanks for the comment.

BrightMeadow from a room of one's own on June 15, 2012:

I heard about this plant on a television program but they did not go in depth. I'm glad you shared this. I would love to hear more about the uses of other plants that you are familiar with as you mentioned in one of the earlier comments. Thanks for sharing this info.

Mary Wickison (author) from USA on June 15, 2012:

Hi Brenda,

Thanks, I am glad you enjoyed it.

It isn't just about tropical plants, I recently read a hub from a new hubber about what plants grow well together. Interesting info.

Mary Wickison (author) from USA on June 15, 2012:

Hi Angela,

Thank you. It took me awhile but get around to writing it, but now I am glad I've done it. I am pleased you liked it.

Angela Brummer from Lincoln, Nebraska on June 15, 2012:

This is an amazing article. New information I have nerver heard of presented beautifuly!

Joan Veronica Robertson from Concepcion, Chile on June 15, 2012:

Hi, greetings from Concepcion, Chile! This is a great Hub, well in line with some of our school work in the rural areas, the drylands. It reminds me of our efforts with the school project for worms (I wrote a hub about this project, maybe you would like to check it out?) I wish you every luck with your enterprise in Brazil.

brenda12lynette from Utah on June 15, 2012:

Thanks for the great information Blond Logic! I love learning about the different properties of plants. Voted up!

kartika damon from Fairfield, Iowa on June 15, 2012:

Hi Blond Logic - yes the pharma industry is all about making the big money. Nature has a cure for so many (perhaps all) of our ills. Having that knowledge is so valuable - and it's good so many more people are recognizing this. You are so lucky to live where people are close to the land and understand the power of plants and strive to live in harmony with the ecosystem. :)

Mary Wickison (author) from USA on June 15, 2012:

We have a spare bedroom, come visit! There is always work to do on the farm.LOL

I think that when we stop and look at how small communities deal with problems, we can learn much from them. Sometimes, in our search for bigger, better, faster we lose sight of what is simple and more effective.

I'm pleased you enjoyed the article. Thanks for the comment.

Mary Wickison (author) from USA on June 15, 2012:

Hi Kartika,

Where I live in Brazil, there are many people with local knowledge of plants. One we have in our garden, the locals use it if they have dandruff.

Once when my husband had an inflammation on his leg, my neighbor brought over a plant, chopped it up, and put this on his leg. By morning the inflammation was gone.

So often the western world would rather take a pill than use something herbal or natural. Luckily I think this is changing.

Thank you for your comment.

Mary Wickison (author) from USA on June 15, 2012:

Hi Natashalh,

There are different varieties of it but you may well have it there. Sometimes things can be right under our noses and we don't appreciate them.

Thanks for stopping by.

Have a great day.

Mary Wickison (author) from USA on June 15, 2012:

Hello Wilbart26,

Thank you. Remember if you plant it, you have to control it. That is why we have ours in separate ponds. Because it can double every 1-2 days, by 60 days it could cover 79 acres!

Let me know how it goes.

Mary Wickison (author) from USA on June 15, 2012:

Hello phdast7,

Yes, places in the far east, Latin America, and parts of Africa. I have seen some homes that have the manure running into a large cylinder for bio gas for cooking then into a duckweed pond and then into a pool where fish are. It is an amazing plant. Although some people in countries such as Vietnam eat it, I personally haven't. A morning duckweed smoothie? Watch this space.

Thanks for stopping by and also sharing it. Much appreciated.

Mary Wickison (author) from USA on June 15, 2012:

Hello RTalloni,

We first discovered the benefits of duckweed after looking for ways to reduce the cost of raising our tilapia. There is much research going on in the far east and Latin America where they are trying to increase rearing fish for local populations as well as the export market.

Thanks for your comment.

Mr. Happy from Toronto, Canada on June 14, 2012:

"The reason we decided to grow duckweed is to feed our tilapia. We have a farm here in Northern Brazil where we raise tilapia for the local market." - I love Tilapia - I might have to visit to have some fresh! : )

I have heard about the many positive uses of duckweed not long ago. It makes me happy to find that we are re-learning how to use what Mother Earth gives us.

Great article - thank You for bringing this topic to the general discussion, here on Hubpages. Cheers!

P.S. Thank You to Mrs. Theresa (Phdast7) once again today for sharing another great article!

kartika damon from Fairfield, Iowa on June 14, 2012:

Thanks - great article. I'm always happy to learn more about the environment and the amazing potential plants have to heal people and the planet.

Natasha from Hawaii on June 14, 2012:

So cool! I think we have duckweed growing at work. i always just thought it was some weird plant. I had no idea it was so useful! Thanks for putting this hub together.

Wilbart26 on June 14, 2012:

This is a very informative hub about duckweed, I never thought, duckweed is this helpful. Thanks for this, I might consider planting duckweed also... Very helpful... Keep it up!

Theresa Ast from Atlanta, Georgia on June 14, 2012:

This is absolutely fascinating. I had no idea. What a marvelous way to do so many things. Do you know if this is being done in many locations, many countries? Terrific article! Sharing.

RTalloni on June 14, 2012:

How interesting! You have done a wonderful job of explaining why as well as the way you are growing duckweed. I'm not surprised that it we would discover that it has many benefits, only that the news is not more well known.