If you mention Azolla to people who sell pond supplies they will probably tell you that it is an invasive species and you should avoid it at all costs. But if you do a little research online you will also find that there are people calling this ancient floating water fern a superorganism!
Azolla is no newcomer to the plant trade – it has covered water surfaces on our planet for over 50 million years. There was even a 800,000 year period where it covered the Arctic ocean – which was not salt water at the time – or frozen! It’s called the “Azolla Event”. It has been used as a nitrogen fertilizer in rice paddies in China and Vietnam for at least 2,o00 years. It was used as poultry feed in Peru at least back in the 1700’s when the Spanish recorded it’s use – so probably much further back than that. Because it has evolved symbiotically with a bacteria that helps it to draw nitrogen from the air as well as the water it is growing in, it is capable of doubling it’s volume every 2 or 3 days in warm weather!
Here’s a little video of an Azolla harvest in a rice paddy.
As I mentioned in my Chicken Feeding post it has been found to contain 25-35% protein which is not something that many plant based foods achieve. Protein is an important ingredient in the food of animals that lay an egg nearly every day. Most grains and seeds reach only a 9-15% protein and most of those are not something the average home gardener can grow and harvest in any sort of quantity – like wheat and oats. And grow without giving up any garden space. I read (haven’t tried) that it will grow in just an inch of water.
It’s an interesting plant because it’s so very easy to grow – even if you can’t grow other plants you will probably be able to grow this one! I haven’t read of – or experienced – any insects or diseases that bother it. Heat and cold will slow it down – and enough cold will kill it. Did I mention that it doubles in volume every couple days?! That’s a pretty nice return for your effort and expense, considering that it’s not just a good animal feed, but excellent compost and soil amendment material (you just mix some in a planting hole as you plant). It could be used as bio-fuel and one of the things that I keep reading about is it’s ability to sequester CO2 from the air… Some studies also found that it is very efficient at pulling heavy metals and other toxins out of the water it is growing on.
It’s also a plant that makes good people food. Well maybe not good exactly… I gather it tastes a bit like grass and so far I don’t think they have found many recipes for making it yummy, but NASA was studying it as a plant that could be taken and grown on long space flights. At any rate – in a pinch you could eat the stuff yourself… and give a start to everyone you know.
It dries rather easily and can be fed to animals in a dry form as well. That might be an answer to the lower supply in winter. I’m planning on setting up some tubs in the greenhouse this winter but I think it will likely just keep it alive and not actually give us very much to feed. We will see.
In spite of being a plant that is probably best kept out of wild waterways because it DOES grow so darn fast and clog things up in some situations – growing it in a home/farm pond – whether you have animals to feed or not – is probably a worthwhile addition to any permaculture setup. It does need to be harvested fairly regularly – but nothing awful will happen if you miss a week or two while you are out of town on vacation…