Comfrey Powered Urine Nutrient Redeemer

Hi folks! I want to share a project I have been trying out to recycle urine with comfrey plants indoors in buckets, which may be useful here in Maine during winter when it's less fun going outside. I'll try to update with some pictures from my phone soon.

I have a lot of 5 gallon buckets. One restaurant nearby has stacks of them for sale for $2.50 each, and I hear that other restaurants in the area give them away for free.

I have made a couple prototype nutrient redeemers/recyclers so that I can use urine for plants without having to go outside, where I usually go when it's not winter time here in Maine.

The basic design is a bucket, with the bottom 1/3-1/2 full of a mixture of biochar and some absorbant carbon rich organic material. I used peat moss because I had it on hand, but really peat moss is usually un-sustainably harvested so if I didn't have it on hand that I was trying to use up, I'd probably get some choir or something similar.

On top of this layer is a thick layer of wood chips, within which I have planted three bocking 14 comfrey plants. The comfrey plants will, hopefully, grow their roots down into the spongy layer down below and bring those nutrients up into their leaves. Comfrey can handle urine, or at least 50/50 urine/water mixture, and seem to be able to handle being pretty wet so far.

I've also created a urinal out of an old plastic soda bottle with a whole cut into it, which I duct taped to a pipe. The pipe gets put into the middle of the bucket, such that the bottom of the pipe is about at the top of the absorbent layer, and below most of the wood chips. Whenever I urinate in it, I spray the inside of the bottle with a little water to flush it down and also dilute the urine somewhat.

I am experimenting with different plants, but I don't have any real data so far. I expect that salt will be an issue eventually, and so I've ordered some propagules from a plant which can both handle its roots being submerged and can handle lots of salt, and actually move the salt up through its bodies and out of the soil, and this plant is the red mangrove Rhizophora mangle. It's a tree, so it might be impractical in buckets but I was curious. Asparagus can also handle salty soil, and I would like to try that as well but my asparagus bed is frozen right now. I'm not sure if they move the salt up into the shoots, if so and if they grow well in this environment that could be very useful (perhaps some other herbs may also work, like mint?). I could also drill holes in the bottom of the buckets so that I could flush them out periodically with rain water, but I want to get some plugs or gaskets or something before I do that so that I can plug it up and not make a mess inside.

I now have two buckets and plan to make more. I'm guessing that 7 buckets may accommodate the urine from one person by moving the urinal to a new bucket each day. In the second prototype I added some azomite and wood ash, with the thought that these may provide some nutrients that are lacking. In future ones I want to try adding a layer of soil between the thick layer of wood chips and the absorbent layer, and perhaps some where the soil or sand and absorbent materials are mixed in a layer. I'm out of comfrey plants right now, so I need to work through that bottleneck If I were short on space, I might drill small holes near the top of the outside of the bucket, and plant the plants in there instead of on top, which would allow for the stacking of buckets, although it may increase the chance of a spill.

I propagate my comfrey plants in tubes, which I got when I ordered some chestnut and hazelnut seedlings. These allow even a very small comfrey plant to have really deep roots, without taking up a lot of space. I will definitely propagate them this way again (I took some tiny side-plants from my biggest comfrey plant and put them in the tubes in the green house, they've been growing steadily even in the cold and when I planted them, the roots were probably 7-8 inches long).

Between rehydrating the peat moss and over-zealously using my first two prototypes, they are more full than I meant to let them get. The liquid layer is maybe 3 inches from the top of the wood chips. The comfrey plants really don't seem to mind so far, but we'll see! I have put a small light on them to help them work through all that liquid.

Eventually I want to do humanure composting, but in the meantime this will hopefully help me create a nutrient cycle and save my pump and septic system some work. I think it could be useful for people in cities who can't compost humanure too.

Curious about light in your set up.
Window? Grow lights? Other?

Hi William,

Right now I have them in a sunny window. Since we're so close to the winter solstice, and because there's some stuff blocking the light, I've been giving the two buckets I have some supplemental light from a regular CFL in the evenings. I think they'd survive being in a greenhouse even in the cold. Once it warms up outside, probably around sap season, I'll bring most of them out onto the sunny porch and just have one or two inside to use.

Since I had over-filled them, I poured a little out from each bucket onto a hazel shrub's roots outside. The comfrey didn't seem to mind the high liquid level, but it looked like it would take a long while for it to get through it all.  I expect their ability to go through liquid will grow as they do.

Here's a quick pic I took. The comfrey on one of the buckets may have a little leaf burn, but I also just took them in from the cold greenhouse and transplanted them. Anyway I have poured some of the liquid out and the plants all look fairly perky.

Good job, Jason!  keep us posted on your piss project!!  It's a good one!

Will you tip the whole thing on a garden bed later or is it meant to stay in the buckets?

Thanks Roberto!
Angelika, I poured some out because I felt I'd over-filled for what the plants can handle, but I'm hoping it can mostly work without having to pour it out, by the comfrey moving the nutrients and water into their leaves, which can then be used in the garden (or dried and stored for later). It would be easy to add a spout to the bottom to drain it though, and pouring it wasn't hard. I just gently held the wood chips at the top and tipped.
I'm having buyer's remorse with the red mangrove, I'm sure there's something smaller and more suitable to my climate that can move salt up and out, or a periodic rinse and pour/drain could remove salt, but I'm going to give it a go anyway.
I'm thinking that well rotted wood could be used instead of peat moss. Everything is frozen and covered in snow here right now but when it warms up, I'm going out into the woods to get some and try.

Here are a couple of plants that claim to have a tolerance to salinity:

Blanket Flower - make your pee buckets purdy! Not sure how much organic mass it produces.

Rosemary - smells good!

Yarrow - this one will produce more mass than the above two obviously.

Pretty cool idea - I'm going to see about setting up a girl powered one.

The yarrow might be able to companion with the comfrey, as they have quite different root systems.  They are both used in biodynamic preps, and are said to have great properties for compost making without the extra charge so they should be awesome.

Starting to see new growth in the comfrey in bucket #1 since planting them. Some oat grass is sprouting as well, I planted them mostly to keep the comfrey company while they're young but the right grass might do well in a system like this. I planted some corn in the other bucket but that has not sprouted yet and I'm not sure how it'll fair growing in wood chips but that's what experiments are for.

cool!!

I'm gonna try this at my allotment I usually just add my pee to the compost heap or the liquid fertiliser tub, but I love experimenting so this one's going on my list!!

Linda

Thanks for the plant ideas Tracy & Roberto!

I'm going to try yarrow, it'd be good to have that plant on hand, it's supposed to be great for stopping bleeding.

I'd love to have a nice bushy rosemary plant, but I keep killing them >_< They seem to like it pretty dry, but it's worth a shot.

Linda, let me know how it goes!! I love peeing outside most of the year, but this has been a fun experiment so far and tickles my gardening bone in the winter. Comfrey is one of my favorite plants, it's just so relentless in its growing and bounces right back whenever I cut it. I was missing it, and it's nice to see it growing again

Someday, I hope even cities will collect urine and pipe it to plants, instead of into rivers! I bet plants are as grateful for our leaks as we are for their oxygen and fruits. It's a fun and easy cycle to make.

I'm not sure how corn will do with damp feet.  Rice might be better.  Perhaps it might be worth your while in the spring to go to some feral meadow creeks in your area and find what grasses are growing right on the edge of the watercourse. These would be adapted to having damp feet, and might be a better choice.  Comfrey is a great choice, since it is a riparian (streamside) plant, that seems to do alright in very damp places.  I'm not sure how well it will do in a pool of piss over time, but I do think that a person can come up with a way to flush the system a bit so that it isn't too pissy.  

Rice is a really interesting idea. People are starting to grow rice in Maine, I'll try to get some locally adapted seeds. One local farm ships them in the spring but I'll keep looking. Exploring local wild areas is a great idea, I'll do that in the spring. There are lots of cattails around, I seem to remember reading about a permitted constructed wetland septic system at an eco school somewhere in the state, maybe they'll have pointers.

Bucket #1 is looking good. Comfrey is making new leaves, oats are coming up, strawberry is shiny and mangrove is grooving.

I made another bucket with a thicker absorbent layer when I found a couple more comfrey plants.

Hi Permies, just wanted to give a brief update:

The comfrey is still growing in the three buckets. I've pulled one of them out, cut the roots and put the pieces in potting soil to propagate it so I can try more buckets. I would like to try one with clay below the wood chips, which I've read comfrey enjoys and I think would be good for soaking up liquid (I have mostly sandy soil here but local friends have offered me some of their clay). The red mangrove doesn't seem to like the conditions. The oats and corn are still alive, it's hard to say how they are doing because my cat really likes chewing on the oats (and trampling the comfrey). I'm also sprouting some rice which I'll try in a bucket once they're going. The strawberry plants look good so far. I don't think their roots go down into the pee layer, but borage I hear is a great companion to strawberries and comfrey is borage's cousin, so maybe they'll be buddies.

If I had them available, I'd start with larger crown cuttings instead of tiny plants from root cuttings. I think then it could process both more liquid and more nutrients. The plants are still small but light is short this time of year and they started pretty tiny.

As I may be selling my house sometime soon to downsize, I'm really treasuring these buckets. I feel like I can build and hold on to some fertility which I can bring with me wherever I'm going. The comfrey plants cheer me up with their relentless growth and perkiness. I'd like to get into composting humanure, but as I may be moving within a year it seems like it might not be a good idea to start a pile outside, I am working on trying a bucket with humanure, some layer(s) of odor-preventing material, and a comfrey plant atop the humanure. I'm in the bucket filling stage right now, using coco coir on top of deposits. When I move, I can cut the comfrey, put the covers on the buckets and stack them to bring them wherever my next place is.

I'm curious to try out willows. We had a severe drought this past year and I probably lost most of the willows I planted last spring (just couldn't keep up on watering), but I at least have some pussy willow I can try. Eventually a smaller, native willow adapted to re-sprouting after being cut that's useful for medicine and/or crafting would be wonderful.

Hey,  I  just want to share how you inspired me.
My comfrey is soaking up rabbit water and not pee, but it's growing and I'm feeding it back to the bunnies.
Thanks for the ideas you share here!

One word:  WILLOW


Keep cutting it back as it grows. Then there are dozens of uses (maybe even 100)  things you can do with the willow.
Head over to Michael Dodge's   Willow World for inspiration.

What a cool idea! In the south, winter doesn’t discourage my menfolk from going outside but I really like your idea. I put jugs in the bathrooms for use on the corn and it seems to love it but I don’t know how it would deal with constantly wet feet, maybe you could rotate buckets enough to keep the level below their happy place.

Horsetail is a bamboo cousin and has an absorbable form of silica so good for teeth and bones, I’m told. I grow it year round in the greenhouse and it thrives in the horrible heat of summer as long as I let the hose pipe drain into the half barrel it lives in, most days. It loves wet feet but I don’t know how it would feel about your nutrient mix. It does seem to be extremely tough so might be worth a try.

Jason Ouellette wrote:Rice is a really interesting idea. People are starting to grow rice in Maine, I'll try to get some locally adapted seeds.  

This is my preferred way of using a hole in a 5-gallon
bucket.

This bucket is fed from another bucket next to the rainwater
collecting basin. That is positioned higher so that when
it empties, this is full. The top manifold overflows
into the drain further downstream.

I have another bucket with 3 manifolds at the bottom. It is
filled with chunks of biochar and is used to buffer the
bathwater and deliver it to two clumps of banana plants.

You need to drill a hole thus. Ram the hose joint tight
and pump in glue from a hot melt glue gun. A 20mm hole in
the bucket and you are good to go. You could cascade
buckets this way. The hole is suitable if you want to
swap the manifold with a cheap plastic tap.

I can easily make this watertight by attaching a short
length of hose and secure the other end of the hose to the
rim of the bucket. A rubber bung would suffice but it
carries the risk of an environmental disaster.

We have a rather simpler system. A little distance from the house is a composting outhouse, That gets very little pee, and has a bucket of sawdust to throw a handful in after a deposit, so it doesn't smell. The buckets get emptied, when four are full, in one of a pair of concrete block bins somewhat farther from the house, and leaves top each layer. In spring I clean out the side that has been undisturbed for a year, use it in my orchard and flowerbed, then start dumping into that side for the next year.
Meanwhile, we have in the house what I call a pisseria. This is another five gallon plastic bucket, with a wooden shelf with a toilet seat built into it and a few chunks of wood nailed to the floor such that setting the bucket within them positions it so the toilet seat fits securely onto the bucket. Keeping the lid down keeps the smell down--urine contains most of the nitrogen and phosphorus we pass, while almost never any pathogens, so saving it is only sensible--but it's nitrogen that makes it smelly. TP goes into the compost can or the woodstove. When the pee bucket is half full, I dump it over the next in a sequence of about ten compost piles I have around our clearing, to hasten decomposition. I tried using it, diluted, as fertilizer just a couple times and didn't like the results so I now use it just to speed up my compost piles. I have one beside each of my four garden plots, and several in the woods, where I've raked together heaps of half-rotted logs, fallen branches, maybe some leaves. Sometimes I have a wood chip pile which can certainly benefit from a shot of nitrogen.

There was a big hydroponic tomato growing setup in south FL back in the 60s and 70s that used sea salt and a bit of nitrogen as the main nutrient.

It was  Dr Maynard Murray who figured this out:

"Thus, all of the essential nutrients can be supplied in the proper proportions by using a single solution consisting of diluted sea water plus nitrogen. Preferably, these solutions are obtained by dissolving complete sea solids in fresh water to form dilute solutions containing approximately 1,000 to 8,000 parts per million of sea solids."
- Dr Maynard Murray from Sea Energy Agriculture

The tomato farm passed through two other owners, Don Jansen and Robert Cain. Robert is still processing and selling the sea salt as Sea 90. A bit of digging in your favorite search engine will get you more detail on all this.

Don Jansen switched over to growing oat and wheat grass in the salt solution to be dried ans sold as a nutrient substitute.

https://cs.agro-club.net/video/ocean-grown-vegetables-don-jansen-sea-energy-5214

What I'm getting at is that you might try tomatoes as a very salt tolerant plant and you're right on track with the oat grass.

I've also read that beets and brassicas will take a lot of salt.

https://onlinelibrary.wiley.com/doi/10.1002/jsfa.7097

This is a LOT of salt  on those brassicas, 100 mmol per liter is a teaspoon of salt per liter


If you want to track what's going on in the liquid you can buy inexpensive PH and EC meters on amazon or the like.

PH you probably understand but EC is a measurement of electrical conductivity...which is how much salt there is.
This way you can record your results, spot changes per amount of material added, and see how much stability on salts and PH that you have.

Example - Just using these two cheap meters I was able to figure out that my alkaline water, run through acidic pine bark in a dutch bucket setup made the perfect hydroponic solution and held correct PH indefinitely.
Most hydro operators are constantly having to tinker with pH going too far one way or the other.

I adjust the sea salt and nitrogen in the hydro solution via the EC meter. Too much nitrogen to the tomatoes and you get lush green growth and minimal to no tomatoes.

Jason Ouellette wrote:
I am experimenting with different plants, but I don't have any real data so far. I expect that salt will be an issue eventually,...

May I suggest looking into some native plants that have high tolerance to salt.  There are both herbaceous perennials, such as seaside goldenrod, Solidago sempervirens, which has beautiful flowers, and shrubs, such as  Beach Plum, Prunus maritima, a salt and cold-tolerant shrub that bears edible dark purple-red fruit that ripens in late summer. There are numerous native plant, wildlife, and pollinator groups who maintain websites with extensive information on native plants and also provide search functions with which you can specify site requirements, such as zone and salt tolerance.  There is much to find there. Audobon, National Wildlife Society, Xerces society, etc. to name just a few.

I'm looking forward to your continued experiment with this idea!