Backyard Aquaponics
A place to discuss aquaponics

A couple of recent posts have included questions about drying duckweed.

My initial reaction was to question the need but I failed to take adequate account of the fact that there are some people who don't live in Queensland and who, for reasons of cold weather, might need to stockpile duckweed against the time when they run short.

To address this need, I conducted a hastily assemble 'drying trial' where I scooped some duckweed out of my tank and threw it on the ground. Two days later, I happened across the stuff on the ground and, when I examined it more closely, I discovered that the tiny leaves had dried and flaked off the long roots to which they were attached very easily.

While my 'trial' lacked scientific rigour, it did demonstrate that duckweed is easy and quick to dry.

Simply harvest the duckweed and lay it out to dry. Somewhere sheltered and warm.....I think a cold frame of the type that gardeners use to raise seedlings would be ideal. Make sure that you turn the drying duckweed regularly. When it's dry, store it in an airtight container and away from the light. This will help to offset the loss of vitamin content.

I took a small quantity of the dried leaves and chucked them into my wife's aquarium. The tiny leaves resembled some of the flakes that fish seem to relish and, like all good fish food, they float and they'll get eaten before they have a chance to pollute your fish water.

The fish had been fed a few minutes earlier so the couple of large Angels and Clown Loaches ignored the leaves but the Rosy Barbs got stuck right into them. I'll leave this to you tropical fish enthusiasts to make of what you will.

RIRDC commissioned a report by Bio-Tech Waste Management which included information on drying duckweed. They concluded:

"While it was never intended to be a permanent method of drying the duckweed, the plastic tunnel house at UNE has been the method used to dry the majority of the duckweed used in the feeding trials.

Generally BTWM dried approximately 800 kilos of duckweed at a time, and depending on the amount of sunlight and the minimum and maximum air temperatures, it took between 5 and 8 days to dry the duckweed.

The plant was spread out on the floor of the tunnel house and was turned over twice a day. The only operating cost is the labour required to turn over the duckweed to ensure that it dries out evenly.

The biggest disadvantage of using the tunnel house is the inability to insulate the structure and retain the heat after the daylight hours."

You can read more about BTWM's duckweed trials at http://www.rirdc.gov.au/reports/NPP/BWM-1A.doc

If they can dry 800kg lots of duckweed using the methods I've described, you won't have much trouble sorting what you need.

I hope this offers some hope to you climatically-disadvantaged Southerners.

Gary

I only wish I had a pond big enough to grow that much duckweed!

Thanks Gary, your posts are as always, thorough and very informative. I'll be one of the ones drying due to my climatic issues

I've found that my angels are picky with food even when they are hungry

Steve

Yep excellent info Gary, not sure if I'll be drying myself, but at least I know how now...

okay, now you boffins of duckweed tell me just what the [glow=red]@#%^$!**!@![/glow] !!! I have on my finger in the pic below - I know the "bigger" plant is duckweed, but what the heck is the other small stuff??? It does nothing except multiply!

Gary will be able to answer that! Maybe a tiny species of duckweed?

AM, that stuff is really small. Might be a different variety, but my baby duckweed looks like the big one you have on your finger. The other stuff does not look like any duckweed i've seen, maybe it is something else.

which is why I posted a photo... I am stumped by the stuff, and it feels like gritt when you rub it between your fingers...
Anybody seen this "stuff" before

My guess is that you're holding onto several hundred plants of the duckweed Wolffia Angusta Landolt.....a native of northern Australian and Malaysia.

The plant body is 0.6-0.9 mm long and only 0.2-0.5 mm wide. It is one of the narrowest of all species of Wolffia.

If you'd like to know more about this plant, go to http://waynesword.palomar.edu/plaug96.htm#angusta

I just took another look at the photo. Make that "several thousand plants.'

AM, "tag it" Steve.

lol, but serious

Tagged LOL

THanks Gary - now to see if it is any good as food for fish....

So has anybody deatl with this sort of duck weed before? Is it worth anyhing as fish food?...

I got duckweed from a volunteer fire department's duckweed-covered retention pond "trespass at your own risk", and there was a lot of what you have mixed into it. I thought they were baby duckweeds! Some of the duckweed looked like fractals, where there were several copies each smaller than the previous attached one, and I thought that they reproduced like that...

Know your duckweed, d*ckweed! :
http://aquat1.ifas.ufl.edu/duckweed6.jpg

Little ones:
http://aquat1.ifas.ufl.edu/wolcol.html

Harvesting in Thailand:
http://waynesword.palomar.edu/imgwotha.htm

Good on chips, crackers and toast!:
http://waynesword.palomar.edu/images/wolfidip.gif