Mar 282021

I’ve tried a few more nutrient cocktails and so far the clear winner seems to be boiled dirt. Just dirt works too but then you have little critters zooming around eating the watermeal, boiling first puts a stop to all the zooming. I’ve tried most of the easy DIY fertilizer suggestions I’ve found online plus some additives to try to capitalize on the mixotrophy, not that I know how to do that or anything, by why not. I can’t tell if adding sugar helps the watermeal any yet since mold seems to eat it all first. Still really curious about the sucrose angle and I’m supposed to pick up a bucket of ‘sugar press mud’ from a sugar mill next week so we’ll see how that goes.

Since a lot of learning to grow watermeal means leaving it alone I’m spending a lot of time thinking about and fussing with the little grow boxes. That’s probably become the real reason for all this. I’ve had a bizarre affinity for boxes since I was a child and somehow making and fussing with these is just tremendously satisfying.

So I got some more 80\20 and built a second one and I have most of a third but ran out of parts to attach the light. I removed the pi controls for now since I’ve already decided that needs an overhaul. For now it’s all just on a power strip toggle.

The cardboard panels leak light quite a bit but I’m going to add some foil baffles at some point. The foil lining on the inside probably helps a lot with the light but I haven’t metered it yet. One box has a 50W and the other has a 20W LED.

This is the kitchen-lab-garden at present. You’ll notice one box has actual potted plants- those are two jimacas and something that’s growing where I planted a muscodine seed, but doesn’t really look like what I thought a muscodine looked like. I have two more jimacas outside. Of 20 jimaca beans only 4 germinated so I’m pretty proud of these little guys. Not sure what’s up with muscodine guy but we’ll see. Since there are 4 jimacas and another thing I’ve named them Terry, Korvo, Yumulack, Jesse, and Pupa.

I switched up the BlueBox to be sort of a macro-time-lapse thing to give me imaging data to figure out how to maybe visually quantify growth.

Mar 142021

The watermeal stuff made me want to zoom in so I got a $15 USB ‘microscope’ off eBay. It says it’s 50x-1600x but I don’t really know or care enough to check them on optics but it zooms pretty hard so I was pleased with the purchase.

Before long the frustrations of focusing and moving at tiny scales made me wonder how hard it would be to motorize it. Seen a lot of DIY builds with the DVD drive steppers and I had a couple and drivers so I started soldering wires onto those annoyingly tiny flexible pcb leads. Naturally the frustration of that process made me question my whole existence and I stopped long enough to remember I have a perfectly functional motorized XYZ in the form of a MP Select Mini v1 that I got tired of replacing the heater block and fan on. It’s always amusing and infuriating to me how long it takes me to get to the most painfully obvious solution even when it’s sitting in my closet.

I had a couple of bad ideas on how to fix the scope to the heatsink but eventually I settled on a 1/2″ square dowel drilled to hold zip ties. Then zip tie the dowel to the scope and to a machine screw held in the sink with washers and nuts. It’s rigid enough to manually adjust the zoom on the scope without bumping the frame so that works for me. I forgot to home the Z axis before I strapped on the scope so I’m not 100% sure I won’t crash it into the bed, but this is for moving around in spaces of a couple of centimeters so this works. A less lazy person would have used their perfectly functional MP v2 to make a neat little fitting, but I am lazy so when a drill and zip ties can get me there the printer stays off.

The scope has a built in LED but I added a 12LED RGB ring for more control of the light. The separate RGB channels does make some weird effects at this scale, but I think it makes everything look kind of like a nebula with space monsters and this isn’t about real science so I’m good with it. I should have wired the LED for gpio control but I’m lazy and I already made a bunch of ESP-LED things so I just velcrowed one on.

I actually haven’t done much to justify motorizing the scope yet. It lets me get some super sharp focus by adjusting the Z though. Also for what I’m doing I probably can only use the X and Z since Y would jiggle the water. I’m just doing stationary timelapses for now because I’m pretty far from coding anything that could help the camera follow a pod, but it’s a start.

The motors and camera are easy to control with python, fswebcam and gcode. I could probably send packets to control the LED from the same script but not sure I need that. And the original MP select box with a door cut in the front made a perfect housing for the whole thing.

Mar 132021

So new theory- Wolffia Arrhiza aren’t just people-free soylent-green… they’re also teeny-tiny Audrey II’s.

I didn’t get what mixotroph meant at first and I still probably don’t, but apparently it means they can eat sugar and grow in the dark. That seems distinctly unplantlike to me, but plants eat bugs and sadistic dentists- so why not? Anyway it’s pretty freaking amazing. I was thinking these things were just solar powered but turns out you can run them on gas in a pinch. Not that you’d want to carry a big supply of sugar to space to feed to your plants but I’m guessing there are other organic carbon sources it can use. Guessing is definitely the word though.

So I’m still getting my head wrapped around the sugar thing but I played with a few other nutrient combos and let them grow for a week in the light cube 12on/12off. Here’s the super-scientific recipies:

Cocktail-A – 1 cup H20, 1tsp white vinegar, pinch epsom salt, pinch baking soda, pinch gelatin.
Cocktail-B – 1 cup H20, green tea, coffee grounds
Cocktail-C – 1 cup H20, 1 pump miracle grow indoor plant food
JAR5 – 1/4Cup Cocktail-A + 2 drops glycerine
JAR6 – 1/2Cup Cocktail-A + 2 drops glycerine
JAR7 – 1/4Cup Cocktail-A
JAR8 – Cocktail-B less
JAR9 – Cocktail-B more
JAR10 – 1/4Cup Cocktail-C
JAR11 – 1/4Cup Cocktail-C + pinch hydroxyethyl cellulose
JAR12 – 1/2Cup Cocktail-C
*filled all jars to flange with H20 and dropped ~20-30 watermeal pods in. Refilled about 50ml H20 per jar twice over 7 days.

Yeah- I don’t know what I was thinking with the cellulose and glycerine, but I had some left from LED\Silicone projects so somehow that justifies poisoning a bunch of plants?

TOP – 9-10-11-12 | BOTTOM 5-6-7-8

JAR5 – No growth, few survivors, crusty maybe mold or something on top.
JAR6 – No growth, fewer survivors, definitely mold on top.
JAR7 – Probably some growth.
JAR8 – No survivors, gross swamp.
JAR9 – No survivors, grosser swamp.
JAR10 – Maybe some growth.
JAR11 – Maybe some growth, but probably not.
JAR12 – Probably no growth.

The results were kind of nasty, lot of dead plants and funk. My takeaway is very no on the glycerine and cellulose. But possibly yes on cocktail-A, and sort of yes on cocktail-C. And hold-up on the green tea and coffee, but still curious. I suspect the green tea has eggs in it. I think that may actually be how those critters from chapter 2 got in there, not dirt like I thought. I left the light cube alone most of the week so I didn’t see the hellscape form again, but the aftermath in J8-9 looks very similar. So I may try that again after boiling the tea.

I think the small containers are their own problem. Too deep for their opening so it’s really stagnant and not much gas exchange maybe. Nutrient levels varying wildly with evaporation. Also I’m not sterilizing anything so life is finding ways. Still thinking about how I’m going to manage all that.

So I’d like to say I’m slowly learning to grow watermeal, but I think all I can really claim is that I’m slowly learning how to do less watermeal mass-murder. But considering this is widely regarded as a weed to be controlled or eradicated- I think starting from mass-murder and working backwards might actually make sense.

I reached out the LSU AgCenter and got pointed towards ‘Azolla’, which was an excellent hint for finding how people actually grow little alien plants like this. And Azolla actually shares a lot of watermeal’s awesomeness. I’m especially curious about how Azolla restricts mosquito breeding- which I thought would be a challenge to growing watermeal outdoors, so I wonder if watermeal can do that too or maybe growing it with Azolla could protect the watermeal.

Also want to give a shout out to the little jimaca and muscodine seeds- they’re trying their best to germinate despite me not knowing what I’m doing so I just want to show them some love. Also big ups to turnip and onion- those are some champs.

Mar 062021

So very predictably I’m discovering that I’ve been doing everything completely wrong. I vastly overestimated the light requirements and I think I sort of bleached a lot of them to death with 50W 24/7. I changed to a 20W LED about 6 hours a day and they seem to like that a lot more. Also I’ve been reading more about what nutrients they need and a little bottle of miracle grow seems to keep them happy for now. At this point I’m still just trying to make sure I can maintain a population of these things at all- then I can get into testing out some variations.

Also apparently I introduced pests in one jar by dropping some dirt in it. Turned into a delightful little hellscape of micro monsters eating each other and the pods and then everything died. I took some video in a USB microscope because it was interesting but not sure what exactly happened there. I like to think it was the plot of Pacific Rim but the trans-dimensional aliens are bacteria and a Class-5 Kaiju is about 2mm tall.

And I got enough 80/20 parts in to put together an aluminum frame box so I can get rid of the wood frame monstrosity. I ordered a MakersLED fixture but it’s been stuck in transit for a few weeks so I just used another heatsink I had and it does okay with a fan on it.

The raspi just controls a relay for the light and a USB webcam for now. Apparently I’m too dumb to correctly wire a dallas 1-wire module so not taking temperature readings yet.

I’ve been doing more causal ‘research’ and I’m pleased to find out I’m way, way behind on discovering how awesome this plant is. And though my assumptions on how to grow it were painfully misguided- apparently my assumptions about its potential value are shared- and actually pretty well proven.

This article in particular says “A closed plant and animal system has been tested with Wolffia Arhiza because of its rapid rate of biomass production. The system is designed to function for a period of two years” which basically says everything I wanted to do with this plant has already been done. But- if some goon with no expertise in any relevant field can do some of it in their apartment- that’s probably a positive step too so I’ll just do that. I actually haven’t looked up the reference for that claim yet- but I’ll probably get to it eventually after enough failures.

Here are some other links I’ve found about watermeal that I only vaguely understand but seem cool and interesting.









Feb 262021

I’m having a lot of fun with my new watermeal obsession and I’m going to use it as an excuse to pontificate on all kinds of topics that are only vaguely related to trying to grow watermeal. So here’s some of that.

I’m not really a plant person. I used to say I had a ‘black thumb’ because things I grow tend to die. But I don’t really have a large enough dataset to say even that. I grew corn and tomatoes once. I’ve thought about growing algae for a long time. And I couldn’t keep a peace lily that my grandmother gave me alive even though I really tried. Those three sentences are pretty much my entire horticultural resume. So it should probably be odd that I’ve decided that it’s my duty and pleasure to unravel the mystery of ‘least duckweed’, but it makes sense if you’re me.

I’m a life-long technology geek. Anything from a steam-engine to a space-ship is worth knowing about. Not that I ever thought that plants were outside the realm of technology- agriculture was humanity’s earliest and most important technological masteries . But me and plants never really made friends. I get them from a molecular-engine kind of perspective, but they have a shit-load of inputs and variables I have no man-made analogy to help me understand. They’re kind of black-box, proprietary hardware and software with no documentation. All you can do is try different inputs and log the output. Also they’re just kind of slow.

But I want to know about duckweed, and it seems like more people want to kill it than grow it, so I’m running into a newish situation where I want understand something that there’s not much information on, but it’s way outside my experience of how you go about understanding a new thing. I’m used to the limited information part- but only in areas where I have extensive context to figure out the information I need.

I can’t take watermeal apart or examine its source or logs. I can’t compare its function to something I already understand, there are no schematics or pinouts, and I can’t take a snapshot before I try something crazy and then rollback when everything blows up. It’s like someone handed me a completely alien technology that creates food from nothing and I’m not even sure which side is the front.

Of course I’m exaggerating, I know some basic biology and I read so it’s an ‘alien technology’ that humans have been studying for thousands of years, but I’m not those humans right now so it’s still kind of new to me.

I thought I had a pretty good understanding of scientific methodology and sort of practiced it in problem solving for work and DIY projects and whatnot. But messing with alien plant technology has forced me to face the fact that I’ve never actually employed the scientific method on nature, only on human devices. What that means is I’ve never really employed the scientific method at all. I’ve employed intuition and deduction in a context where I had sufficient knowledge that I didn’t really need to be all that scientific to find the solutions I needed. I can’t rely on any of that to figure out how a plant works.

So what do I do to prepare for this new challenge? Do I try to become the rigorously methodical scientist that I like to imagine I could have been if I wasn’t a lunatic? Sure… maybe while I’m at it I’ll become an unflappable, cool-headed operator who can pilot a lawnmower through a hurricane. I’ll get right on that. No- I think I have to do this the way I do everything that I’m not paid to do- with no regard for anything except whatever I feel like doing. It’s a sort of casually-aggressive dilettante-ology style of learning. It may or may not accomplish anything useful, but it keeps me entertained.

It is kind of fun to keep looking at this as a technology problem- the alien black box thing. So I have this device, but I don’t know anything about the designer’s intent or record… or do I? Actually- in a lot of ways evolution is a far more consistent and reliable designer to make assumptions about. I know evolution only cares about what works- literally nothing else matters. Path dependency adds a potential weirdness factor, but other than that I can safely assume if something works a certain way, it’s because it worked that way when it really, really had to for a bunch of millions of years. That’s actually pretty liberating from a technology analysis standpoint. I don’t have to consider any human stupidity, arrogance, or greed at all, none of that even existed when these devices were designed.

I find myself asking questions like “was watermeal designed to adjust its reproductive activity in response to evaporation?”. And of course nature’s response is “wtf does evaporation mean?” So I have to consider what inputs watermeal would have available to ‘know’ that evaporation was happening or what to do about it. I figure it might ‘sense’ that slowly increasing concentrations of nutrients might indicate evaporation. And maybe that causes it to adjust its reproduction energy. But the ‘meaning’ of those changes in concentration would depend on the volume of water, so maybe it derives even more complex situational awareness with a ‘memory’ of the state and rate of change of nutrients. And now I get to figure out how to design an experiment to test that. This is fun.

I’m personifying watermeal and implying it has ‘intent’ out of literary habit, I should probably stop that- but I wont. But I like that this is still just inputs and outputs, just like technology should be.

But with technology the default state is non-functionality. If a technology works it’s because somebody made it work. If it breaks- well, that just happens eventually unless you keep preventing it. Plants are kind of the opposite. Their default state is functionality- otherwise they wouldn’t exist. So if a plant breaks- it means I broke it, but if it grows, all I did was not screw something up.

With technology that sort of justifies perpetually checking and poking at things a little bit. If it ain’t broke- don’t fix it, but you can still poke at it a little to understand it better for when have to fix it eventually.

With plants I’m pretty sure the poking really, really doesn’t help and that’s a tough adjustment for me. The idea that these fascinating little machines are furiously replicating themselves and I’m just supposed to pop some lights and sensors on and walk away for days at a time is just bananas to me. But I think that’s how this works.

You’d think with all this pontificating I would have something tangible to share that I’ve learned about watermeal, but I don’t think I do, but since I have been messing around with it for a couple of weeks I’ll try to write down a few things about the actual plant instead of making it all about me and what I think about stuff, but that’ll probably creep in anyway.

~Apparently they are pretty hard to kill from neglect, which is great. I put some in clear water with no nutrients and left it in a corner with barely any light and they’re still about half green after 3 weeks. The rest have turned white and sunk to the bottom, which I’m assuming is death- but actually it may not be because apparently they can overwinter as a ‘turion’ thing so maybe they’re doing that but they look kind of dead to me.

~I don’t think they like light 24/7. I’ve only just started to learn about horticultural lighting and spectrums plants care about, but I’ve got a full-spectrum LED that at 6″ gives me the same lux reading as sunlight on a clear day. I’m just using a TSL2561 lux sensor but I figure it’s close enough for now. But at first I was leaving it on 24/7 and quite a few started to turn white and sink. I started turning the light off at night and they seem to be doing better, but all this is anecdotal. I haven’t quite figured out how I’m going to quantify their growth yet but I’m thinking it’ll probably involve learning some more computer vision stuff.

~I still don’t know what nutrients to use, but I’m trying a few things I’ve found online for DIY miracle grow types of cocktails. White vinegar, ammonia, baking soda, epsom salt, coffee grounds, and green tea are what I’ve tried so far. Ultimately I’d want to know how to integrate watermeal into a more complex life-support chemical-cylce but that’s way, way off so I’m just looking for whatever works and is easy.

~Evaporation control is going to be an issue. I’m using fairly small containers and I’m concerned evaporation will make the nutrient levels fluxuate way more than they would in nature and that might not be good for the watermeal and will be very bad for getting consistent data. Fortunately peristaltic pumps are pretty cheap and I can rig up some pi\arduino controls. Also I like that the peristaltic pumps won’t disturb the water that much- at the moment adding water stirs up the surface a bit and makes the timelapses kind of useless for seeing if it’s actually growing. Might be another computer vision opportunity to detect water levels too. Seems cleaner than a bunch of level sensors.

So I’m still waiting on some 80\20 parts for the next testing rig but I soldered up a little raspberry pi ‘hat’ for the temperature sensors, a luminance sensor, and a relay to control the LED, it’ll also have a USB webcam. The plan is to just crontab everything- schedule the light timing, and take sensor readings and photos. I can’t just close it up and leave it for too long because of the evaporation issue, but for now I have a decent workaround for adding water without disturbing the surface much.

No pictures or videos with this post, just a bunch of words. I do have a few weeks of various time-lapses but I’ve been using an ESP32CAM and it’s not great for close up imaging like this so they’re pretty useless. I was surprised I had to use an ND filter in the light box, but fortunately I have an old lighting gel sample pack- it took 6 stops worth, that 50W LED really belts light.

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 – 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.