Does anyone here grow azolla?

Like many of us, I am more preoccupied with fertilizer than usual.
Azolla is cited as a great green manure.
Does anyone here grow it for such a purpose?

I pull algae out of my swale for mulch. It's a good soil builder. I don't think it delivers a high dose of nitrogen though but is a good source of organic matter.

Perhaps I  could do a riff on a kiddie pool grow bag system .
Azolla growing  in the "pool" could be a ready source of nitrogenous top dressing.
My mom just received some arbor day foundation  trees and she wants me to have them.
Planted in grow bags, sub irrigated by the kiddy pool and fed with the azolla,  they might be good test plants for the idea.
Corn is supposed to do quite well in the kiddie pool system as well, and is very nitrogen hungry.
One large dedicated azolle pond might be a better way to go than growing it the corners of other systems.

I am presuming it can be applied and have effect in the same season its grown in, but that may not be the case.

I don't grow it on purpose, but it grows on my pond, like crazy.  The ducks fly in with it on their feet and it gets started.

I scoop it out with a swimming pool net, let it drain in a muck bucket that has holes drilled in the bottom, then spread it around plants.

It's quite aggressive and uses a lot of water, so a small pond or barrels of some sort would allow it to grow.  It's so thick it looks like a solid surface, and it can fool birds, critters that try to go out on it.

Cristo, how long does it take for the azolla to break down?

I have managed to make duckweed endemic to my garden, overwintering and surviving in one or another of my water-feature pots or containers (usually the dishwasher-tub lotus pond).  It grows rapidly in any container that doesn't also have goldfish, which eradicate it via voracious eating.  I used to use it for mulch but now I just scoop it by the handful into the goldfish barrels to feed them.

One season (two years ago?) I ordered some azolla off of eBay and grew it in my containers.  It's bigger and grows faster and makes lots and lots of itself, which I like to pack around the tops of the pots in my container garden as a green mulch.  In hot dry weather it sort of dehydrates into a crusty layer that doesn't break down rapidly, but as soon as the weather gets wet (or if I cover it with other soil or mulch) it seems to break down within a few days.  

I liked having the azolla around but I think it may be tropical; it didn't survive the winter or come back anywhere I had it.  I don't *need* it badly enough to buy and ship it annually.  

I wish I knew more about how these plants survive (or don't) through times of dormancy.  Do they make seeds? Do they just lie dormant in the mud, cold ground, et cetera? A quick Google didn't tell me, the one time I went looking.

William Bronson wrote: Perhaps I  could do a riff on a kiddie pool grow bag system .

I had a ten gallon yellow Igloo cooler with no lid that came from a garage sale for almost free.  I was using it like a small rain barrel and dipping plant water out of it with a dipper.  Somehow some azolla got in there on my dipper and grew so well, it would make a thick mat filling the surface about every three to five days.  Whereupon I would scoop it out with my hands and mulch something nearby.  

All of which is to say, yes, I think it would grow great in a kiddy pool, with or without grow bags.  I like the idea a lot because nutrients leached out of the growbags by rain or watering would be captured and eaten by the azolla, whereupon you just pick them up and put them back on your soil surface!

Being the creature that I am, an actual kiddie pool is unlikely to see  use, but the success you had with the cooler makes me think a fridge or freezer with a clear lid might even produce through the winter!
Overwintering it inside should be easy enough anyway,  it is said to prefer partial shade.

I'm pretty stoked about this idea, perhaps I could even sell dried fern powder as fertilizer.

Keeping things simpler, barrels with ferns and fish might be the way to start.

I wonder, is there a simple way to keep the fish from eating a the ferns or duckweed?

I am thinking to make a pig pit as sacrificial area in the center of my pastures.
This could be surrounded with a trench where azolla could be farmed,
but its still spinning around my head, how that will be done and how this would be working regarding smell and evaporation..

William Bronson wrote:
Overwintering it inside should be easy enough anyway,  it is said to prefer partial shade.

Duckweed I know is easy; just about any vessel with water in it will keep it happy as long as there is a little light.

Azolla is fussier.  The one year I had it, it didn't survive overwinter indoors in the one pot I assumed it would be happy in.  Not sure why.

Azolla filiculoides has been banned from sale here since 2014 because of its invasive habits!

William, it breaks down over months because I cover it with either mowed weeds or wood chips.  It doesn't rain here in the summer, so things break down more slowly.  But it does fix nitrogen so it's got biomass and a little nitrogen going for it.

If I didn't have an accidental source of azolla, and I wanted biomass and nitrogen, I already do encourage native vetches and clovers.  I let them go to seed as much as possible and spread the seeds as soon as I can, without letting them dehisce or drop their seeds.  I mow it all after I get the seeds, which is essentially chop and drop.

It's a lot of work to haul that heavy wet stuff around, and I noticed today the mallard ducks that hang out are willing to dig through it to get to the water, but it's a drag for everybody on a large pond.

Hester Winterbourne wrote:Azolla filiculoides has been banned from sale here since 2014 because of its invasive habits!

Likewise with azolla pinnata here in Illinois.  Probably good to check local prohibitions.

So far I've found no prohibitions.
This is probably because it freezes here in Ohio, so it simply cannot establish itself.

On the other hand Illinois is hardly frost free.

One thing of note, it doesn't seem to like a lot of sun.
This makes me think it would do well inside a translucent white barrel or bucket.
It might also do well under artificial light.
Circulating the contents of an opaque barrel could allow more plants to thrive in a smaller footprint.
An airlift pump might be ideal for this.

I have four 30 gallon white barrels and a line on more.
A barrel of azolla next to each 4'x4' bed might be enough to supply all the nitrogen needed.

I'm wondering if worms will thrive on it.

This isn't azolla, and it's not permaculture,  but this company is producing duckweed for cattle feed, right where the cows are at:
https://agfundernews.com/fyto-the-startup-growing-protein-with-robots-to-decarbonize-agriculture

They use cow manure and waste water, so I'm curious what they do to avoid recirculating disease and parasites.
They are marketing it as food and fertilizer as well as fodder, explicitly taking aim at soybeans and their place in modern agriculture.
Duckweed doesn't fix nitrogen, so but it seems to use it very well and it grows even faster than azolla.

In a homestead context it could cycle nitrogenous waste into nitrogenous biomass very quickly.
Is the nitrogen in urine or feces more available to plants this way or  through direct liquid application?

I have read one source that seems to claim living azolla will add nitrogen to the water it is floating in.
All sources seem to agree it will do as much when it dies.
I have a sub irrigated worm bin crafted from a refrigerator.
It has two compartments separated by screen.
If I grow azolla in one and duckweed in the other, I might create a nice green manure reactor.
Add a  little urine and wood ash, maybe a rusty nail, ground eggshells.

I do grow azolla,in zone 10. It grows very fast at least in summer, but in winter you need less nitrogen anyway: food forest plants it is also great for animals and apparently, they try it for humans (not me for certain!)

Hi,
Azolla does pull Nitrogen out of the air with help of symbiotic cyanobacteria Anabaena azollae, however if water already contains Nitrogen then it uses what's available instead of pulling out of the air. There has been conducted several studies on cleaning water of organic pollutants using Azolla and/or Lemna (mainy N and P)  and it performs this task just as well or often better than Lemna (duckweed).

In ideal environment Azolla grows faster than Lemna in its ideal environment.
An ideal environment for Azolla differs from the one for Lemna. Azolla likes shade or partial shade and grows poorly in full sun, for Lemna its the reverse. Which one grows better in your case heavily depends on characteristic of the place you want to grow it in. In shade/part shade Azolla will thrive while Lemna will struggle or disappear, while in full sun it is the opposite. Azolla has 2 advantages over Lemna - it can pull Nitrogen out of the air if water does not contain enough and can shade Lemna as it is taller.

Perfect placement for Azolla ponds would be ground under photovoltaic arrays. PV's use the sunshine while shading Azolla pond underneath - double use of available land.

Even if Azolla is pulling Nitrogen out of the water (delivered in form of manure fertilization for example) and not out of the air, the Nitrogen stored in its tissues is more stable than the same Nitrogen directly out of the source (manure for example). If it is component of plant tissue, then when incorporated into the soil or dressed on top of the soil, it becomes food source for worms and microbes and holds onto the Nitrogen (and Carbon) in the soil. After the plant tissue decomposition, it is still bound to organic mater in the soil which does not volatize so readily as mineral Nitrogen. It is then made available to plants by microbes "per order" via mechanism of root exudates.

Barrels are not the best containers for growing neither Azolla or Lemna. Both require surface area and do not care about depth (around 20-30cm is plenty). Better way to utilize barrel is to cut in in half lengthwise - that way you multiply the surface area several times compared to barrel stood up vertically.
Or use containers like old bathtubs or fridges.
I prefer to make shallow ponds (around 20cm depth) by either digging a bit of soil and making mound around the pond or making the rim out of logs or concrete blocks. In both methods such shallow pond is lined with cheap polypropylene sheet and filled with water. Quick to make in nearly any shape or size you want and costs next to nothing.

Around 20cm is enough. If you are often going away or you are forgetful and where you live there is not much rain in the summer then its better to make it a bit deeper. That way replacing evaporated water can be more sporadic and you have more time to do that before the pond dries up completely killing the culture.