Backyard Aquaponics
A place to discuss aquaponics

I've got my main grow beds set up and running but I have an additional 75 gallon tank that I'm planning on growing two trees in grow beds off of. I want to build a duckweed table over this tank.

Rather than running my overflow directly back to the fish tank I was thinking about directing it into the duckweed tray. In the center of the tray putting an overflow with a "media barrier" around this overflow to keep the duckweed from falling/ getting sucked into the overflow.
This will allow the duckweed to get the same nutrients the trees get from the fish tank.

What is the recommended depth for a duckweed grow area? Does anyone know if the duckweed sold on Amazon.com will survive and multiply?

May also put minnows in the tray as I've seen others do.


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Oh come on no one wants to comment.


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Sounds like a good idea to me but I've not yet grown duckweed. The minnows would be easy pickings for any predators though in a shallow bed if they don't have a deeper area to hide.

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I wanna know too!!! I want to grow duckweed!

I'm in a greenhouse so unless the predator can open a door I think they will be safe.


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I grow duckweed in worm farm tiers which are floating in my pond. It has also colonised parts of my stream where there are stiller parts (a centimeter of water depth at most). Duckweed will grow in very little water the only thing is it prefers stiller waters so adding depth to your duckweed table would be to slow flow rates and allow it to form a carpet to avoid growing algae.
As for the minnows I have not tried that but I did have tadpoles (unintentional) grow out in the tiers.
Please note its ability to get into the stream which feeds the pond so it could get into any part of your system.

I know nothing about Amazon duckweed.

I hope this helps.

Don't have the link, but saw a very informative video from a professor regarding collecting/growing duckweed. She said you should collect it locally, as it is more apt to thrive in your area. She used Google earth and found a pond 1 mile away from her house. I have a pond a few blocks away...but haven't set up anything yet.

All info is helpful


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I tried growing duck weed for a minute in a tote next to my FT. I just hooked up a u-siphon to connect them. Bought some duckweed from my local fish store (gathering locally would be better). Then I blasted it with light (it was winter).

I had what I would call mixed results. It seemed happy with the nutrients and was growing okay but I lost a lot due to very slight variations in water height(less than a inch). The stuff sticks to everything and if the water fell slightly it would get stranded on the wall around the edges of the tank.

I decided to try again when I had more time to devote to it so I fed the rest to my fish (they loved it).

+1 Sleepe I don't think depth played any role. It should grow in very little water.

When I have time to get started I'll take lots of pics and report about it in my thread about everything else.


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I don't know if anyone is interested a little more in duckweed, I have a few articles but found this one quite interesting.
http://epubs.icar.org.in/ojs-2.3.1-2/in ... /6722/2549

Looks like a good read while at work.


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Hi Binky, I found it!

A couple of things to be aware of:

1. Duckweed needs strong sunlight, and can grow very fast under those conditions.

2. Duckweed does actually consume ammonia directly so if your system is light on nutrients it could put a strain on your plant growth if you have the same water flowing through your duckweed bed and your grow beds.

3. One concern: haven't seen anyone on this forum grow duckweed long term. This to me is a sign it may not be as practical as it seems. It would be great to have someone grow it and give feedback as to growth rates and harvest information that turned into fish feed. (I may also have not seen threads with extensive duckweed growth on it.)

4. If you gather duckweed locally please quarantine it for weeks or months. You don't know what pathogens or pests you would be exposing your AP system to if you just hook it straight into your system. This actually goes for all fish and nursery bought plants too.

Regards, Martin.

Martin

I think Francois from your part of the world has been using duckweed for a number of years. I am not sure if he is still doing so.

Good point about quarantine period...never thought about that. My fish have been very happy..reconsidering the cost savings of making a duckweed growing area. Penny wise, dollar foolish? Fish food is not that much money.