Feb 182021

So my new thing is Wolffia Arrhiza. It’s what most people- including me up until a few weeks ago, would probably call pond scum. But seems like it might be awesome.

It is the smallest known flowering plant, hardy as hell, one of the fastest growing anything, and it’s got some pretty impressive nutritional content. It’s almost what soylent green was supposed to be until it turned out to be people. I just found out about it, which I find unacceptable. I’m going on the assumption that knowledge of this plant has been actively denied to me my entire life. Fortunately whatever overmind is trying to keep me ignorant took a nap and I found out. So- up yours, sleepy overmind.

I guess the required backstory on why I care enough to blame my ignorance of some random plant on an overmind is that I’ve been thinking about planning to maybe grow algae for a long time. Algae because it’s got a lot of potential to be space food. I figure growing stuff that future space people might eat is as close as I can come to contributing to humanity’s future in space, and at worst it’s food for humans, so why not?

Algae always just seemed the obvious answer. There are species of algae that provide all the amino stuff humans need, they can grow stupid fast, and being a goo seems like a minor benefit for space stuff in general. And it seems like NASA and\or sci-fi culture already decided algae is going to be on the menu at some point. It all seemed like a good idea on paper.

The problem with algae as a future space food is that I don’t understand algae and I’m too lazy to try. There are about a billion species, they’re kind of like plants, but also not. They’re kind of edible, but growing them wrong can poison you. Hard to tell the difference between good goo and bad goo without a microscope and chemistry set. Seems like growing space food should be harder to screw up that bad. Astrofarmers won’t all be hardcore biologists so seems like we need something like to a space radish, something you can grow and eat almost on accident.

I forgot where I stumbled on the word ‘watermeal’ but it jumped out at me and I got to looking. Found out it’s part of the ‘duckweed’ family that I’d maybe heard of and probably swum in, but there are several species. The ‘watermeal’ that interests me most is Wolffia Arrhiza aka least duckweed or spotless watermeal. It is used in some limited waste treatment capacities and a cheap food in some regions and has recognized but very untapped potential. Found a few articles sort of lamenting the fact that it isn’t more widely utilized as a food source and explaining how it could be introduced as one. Like this one from 1971 – https://www.nature.com/articles/232495a0. So apparently this isn’t news, it’s just another one of the many, incredibly valuable resources and discoveries that human civilization ignores in favor of more lucrative and unsustainable means. Greed and path dependency make the world what it is…

Anyway- most of the information I can find by googling was on eradicating it. It grows everywhere it can, and really fast, which can be understandably annoying unless you want a thin green mat covering your water, which most people don’t. But if you’re just looking for a highly efficient and robust biological mechanism to create the fuel necessary to sustain other biological mechanisms- well, you’ve found people-free soylent green. Also I read somewhere it can absorb CO2 from the air or dissolved in water, which seems like it could be a beneficial characteristic for use in a life-support system. But I’ll have to read more on how the dissolved CO2 thing works.

Also- most importantly for my petty human culinary sensibilities- it’s a grainy thing. About the size of a grit, so I might actually feel some satisfaction in chewing a spoonful once or twice. Though I haven’t actually eaten any yet, they’re actually much smaller than a grit when dry, so we’ll see how much texture they have. It’ll probably be a long while before I work up to a mouthful of the stuff though.

I ordered a bit off eBay from an aquarium vendor type person and repurposed that BlueBox as a little ‘grow box’- though that’s generous. It’s just a bunch of RGB LED rings blasting red\blue, which I know is not an actual grow light, but I have tons of RGB LEDs so figured why not. I also cobbled together an eyesore of a grow box with a 50W full-spectrum LED strapped to an old CPU heat sink.

A TSL2561 sensor reads about 2000lx under the LED rings and about 11000 under the 50W LEDs, but that’s at about 6-10″. That’s probably not enough light, but one of the things I like about this plant it grows perfectly flat so optimizing light coverage over an area should be pretty straightforward. I’m hoping I can figure out how to use arrays of smaller LEDs very close to the surface. Also curious if they can use light coming from both top and bottom.

I’m working on a more substantial testing rig. I’ve finally found the excuse I need to build something with 80\20 parts so if nothing else it’ll probably look cool. The short term goal is just to consistently grow the stuff. I’m not planning rigorous science or anything, but I’d like to play with a few variables and just see what I can do with pond scum.

So far my observations are pretty limited. It’s green, grainy, and seems to be alive, but I can’t even say for sure if it’s growing or dying yet. I have time-lapses running but they’re not really worth posting. I thought I noticed some interesting collective movement of the grains at first. The box is closed up so shouldn’t be much air moving around in there. I liked the idea that it was doing a semi-colonial slimemold routine and exploring its new environment looking for nutrients using simple interactions like a living cellular automata. But pretty sure that’s not what’s happening. More likely it was just evaporation and thermal stuff moving the water and warping the pan as a bunch of tiny plants slowly die because they don’t have enough light or nutrients because I don’t know what I’m doing.

So we’ll see how this goes. Might be my new thing, or I might get bored or distracted and do something else. Mostly just felt like writing about a cool new thing so this post happened.

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