Introduction: Toilet Tank Bean Sprouter

Picture of Toilet Tank Bean Sprouter

This Instructable is an improvement on a prototype like design that I submitted some time ago. See Semi-Automatic Hydroponic Planter/Sprout Grower. There were some inherent "problems" that I believe to have solved in one way or another. The biggest of which was access to the sprouts. This design has a completely removable grow chamber tub for easy filling/dumping/cleaning.

Having run for some time and not getting sick in the least after eating many harvests, I am satisfied that "I" will not succumb to any potential pathogens able to resist the frequent rinsing with chlorinated water. I'm still more worried about the door knob in any office building or coffee shop than "my" bathroom air. I can speak for no one else. I'm also more worried about the store bought, slimy, sulfur smelling, growth stunted sprouts/salads that come "fresh" in a bag.

If that still worries you, this unit could be placed in series with a drip as well. Anywhere, in fact, where there is a sufficient supply of safe water. A leaky tap (which should actually be fixed ya know), rain water, a stream or drip of any kind that can be fed into the top of the unit and supply coverage.

That being said, the new design incorporates a different and more convenient access grow chamber as well as superior, wall mount bracing. You're on your own if it's pretty you're looking for.

Step 1: What You Need

Picture of What You Need

1 ea "Adjustable Height Wire Hanger Bottle Hanger"... see Wire Hanger Bottle Hanger... or other suitable support mechanism. See that instructable for a separate list of materials and tools and step 2 of this instructable for a photo.

1 ea 2L pop/soda bottle
1 ea 4 inch dia. margarine or yogurt container w/lid
1 ea toilet of the toilet optional...
Flexible tubing as req'd to interface with the tank hardware and create a sprinker/shower head inside the "grow chamber". Because I had a variety of tubing, I was able to something up using the following..... 2 ft of 3/8" OD vinyl tubing
4 inches of 1/4" ID x 3/8" OD polyethylene tubing (it's stiff and it melts to itself)
1 inch of 7/16" OD vinyl tubing (cut into 4 O-rings to act as ring clamps)
2 inches of 7/16 " OD vinyl tubing (coupler)

1/16" and 5/16" Drill bits
Pliers to bend coat hanger as req'd by mere mortals (2 pair)
Side Cutters to cut tubing

The need to flush at least twice a day doesn't hurt either. Actually, it's essential.

Step 2: Bottle Support Mechanism

Picture of Bottle Support Mechanism

Construct some mechanism which will support the "sprouter" a couple of inches above the max water level of your toilet tank. It is important to keep an open air space between the tank water and the bottom of the sprouter or the "drain".

I used the "Adjustable Height Wire Hanger Bottle Hanger" mounted on a 3/4 inch piece of plywood which is mounted on the wall just above my toilet tank. The plywood allows me to NOT destroy the wall as well as act as a spacer to better position the sprouter drain.

See Wire Hanger Bottle Hanger to construct unit shown.

Step 3: The Funnel

Picture of The Funnel

Cut bottom off bottle, with scizzors, near the lower label line so that it makes a deep funnel.

Step 4: Grow Chamber

Picture of Grow Chamber

Drill lots of 1/16" holes in the bottom of the yogurt container.

Drill one 5/16" hole in the lid of the container.

Step 5: HOSE

Picture of HOSE

Make shower head by melting one end of the polyethylene tube and pinching it shut with pliers. I chose this tube because it is more rigid than the vinyl. It also melts into itself when heated, unlike vinyl, creating a more permanent seal at the end of the "hose".
Holding the tube, with pliers at the pinched end, drill several 1/16" holes through the tube in the 2 inches nearest the pinched end.

Cut the 1" piece of 7/16" OD vinyl tubing into four rings.

Onto the un-melted end of the shower head, slip two o-rings onto tube. Then slip tube through the hole in the lid and "lock" into place with the other two o-rings as shown.
Slip one end of the coupler over the exposed end of the shower head as shown.
Slip one end of the 3/8" OD vinyl tubing into the open end of the coupler as shown.

Step 6: Assembly

Picture of Assembly

Place 2L bottle funnel into the holder.
Insert the grow chamber tub (yogurt container) into funnel.
Place lid on container and connect hose to tank water supply to redirect the flow through the sprouter.

Step 7: Operation

Picture of Operation

Fill tub with desired amount of desired beans or other sproutable foodstuff.

Flush away as usual for the required length of time.

Open grow chamber, take tub to kitchen, rinse sprouts yet again if desired, and enjoy.

Repeat as desired.

Mung beans are available at most bulk food stores, are cheap as hell, and take only three days to grow.


razakell (author)2012-10-29

Just a little food for thought, flushing your toilet has the potential to release fecal particles into the air, which in turn could possibly contaminate whatever it is you are growing in this contraption.

Google 'toilet aerosol effect', or follow the link below.

rosewood513 (author)razakell2013-08-16

That is what I was thinking you are right I saw this is on TV I am sorry but this is gross..

luxstar (author)2012-08-26

I did this same thing but without the toilet.

I made a knock off version on the sprouting device they sell at the sprout people web site. I used 2 plastic stackable cups with tiny holes drilled in the bottom of th inner cup for drainage. I used the plastic lid off of a jar of instant coffee for the lid after drilling small holes in it. I also made a supers router out of a couple of small (one or two quart) stackable sterelite stackable storage containers for larger batches

kathynv (author)2012-06-02

What a fabulous idea for that spare bathroom that is only used a couple of times a day, and only by family. I can't say that I'd share the origin of my "toilet sprouts" with my dinner guests, but you're right, my doorknob has far more bacteria than these sprouts.

wiley coyote (author)kathynv2012-07-11

Thanks. Yup... I'd be more worried about E-coli from a bagged salad, but just try to explain that to anyone, especially dinner guests. It's one of those things that just leaves a bad taste in their mouths. It's probably the lack of preservatives.

skeetshooter11 (author)2012-02-22

i agree with maxman

maxman (author)2010-06-10

Dam fine idea. If squemishness is a problem, couldn't you just build some sort of cabinet around the unit to hide it? I'll bet this is cleaner than the majority of produce you buy from the store.

nubiana str (author)2010-03-12

I don't think so. Yuck

awang8 (author)2009-03-23

Toilet tank?!?!

Are you sure this is edible?

dmcunningham (author)awang82009-06-18

The water that goes into the toilet is the same drinking water that goes into your faucet and is no way any "dirtier" than the water that you use to drink and cook with. The crazy part is that we urinate and defecate in to perfectly treated drinking water. Wiley (the author) is putting this safe drinking water to better use before it gets contaminated with bodily waste. So, in short, yes this is edible.

awang8 (author)dmcunningham2009-06-29

I don't think plastic from the cistern and the tube is food grade plastic though. They might have been treated with some kind of crazy chemical, or the plastic might be a crazy cehmical itself.

dmcunningham (author)awang82010-02-26

Your concerns with potential chemical leaching is valid, and something that one should look into before taking on a project like this.

admiral001 (author)awang82010-02-25

Seriously?, you worry too much. if this perfectly good 'ible kills you, then you can complain.

wiley coyote (author)awang82009-03-25

And yet people buy ground beef and poultry everyday ..... Sorry, no offense intended, but I get this argument a lot and I'm not sure why, all other things we do considered. Trust me, if you get ecoli, this is probably NOT the source. I do have to say that this method has produced the only sprouts that I was not worried about eating before rinsing BECAUSE there is NO sliminess or odor to them, at all .... I would normally use those as a sign of bacterial contamination. All other methods I have used have had obvious signs of some bacterial growth. They are enclosed and isolated from the tank itself. Other than that, your fingers and every door knob are more of a threat to your health ... IMHO. I don't get sick, except for the sniffles once or twice a year, so I'm not too worried.

iosononicola (author)2009-11-26

Hi and thank's! I've built up a real "Toilet Sprout Farm" starting from your instructable! Nice Job! You can see my re-edition here (yes... I'm sorry, just in Italian... but with few "good" pictures) ;)

I love it!  Thank you for taking this idea and running with it.

I didn't understand a word, but the pictures made me all giddy... much like National Geographic magazine when I was a kid.  :P

No need to apologize for being a multilingual Italian... I'm a uni-lingual Canadian, and I'm not even good at mastering that.  I'm so ashamed.

aydonis (author)2009-09-06

Great idea! With those that are concerned about appearance or mists of pee, you could always take the plywood backboard a step further and actually find or build a small cabinet large enough to cover the opening of the tank. This should enclose the rinsing unit, protecting it from possible contamination, cover the gaping hole and workings of the toilet, and still allowing easy access to the unit. Just a thought.

sail4free (author)2009-08-14

Has anyone pointed out that the purpose of the water flowing out that little tube when you flush is to go down the overflow tube and refill the bowl; any excess just goes down the drain once the usual 'full' level is attained. There's a similar sink which replaces the toilet lid. Every time you flush, water flows out a small faucet attached to the sink. When the tank is full, the water stops flowing. The difference is the drain tube from the sink goes down the overflow tube. One can wash their hands withOUT turning water on (and touching the handles) at a conventional sink.
I would recommend locating the inverted rinse bottle so most of the water draining off the sprouts goes down the overflow tube to refill the bowl. If there's room enough to reach in there and wash your hands with the sprout rinse water, so much the better! BTW, the vast majority of folks don't let the water at the sink run long enough to get hot enough to make a difference. It just fills the water line with heated water = wasted heat AND wasted water. This is a great idea: using water which is already being used for one or two other things FIRST.
See my ible about building your own growing containers from recycled wood here:


JKibs95 (author)2009-06-22

You are very much one of my heroes right now.... great idea!

wiley coyote (author)JKibs952009-06-22


frithiofandersson (author)2009-01-13

You gotta love this one. Thanks a lot wiley! If I come round to doing this I'll probably have to make some kind of lid for the water reservoir though. For the sake of aesthetics. There is a problem for me though. All toilets here in Sweden have their flush knobs on top, most of them incorporated with the lid in some way. But I guess I could figure that out. Thanks again, good work!

Anytime. Good luck with the design.

Calorie (author)2008-11-19

Yes, I will say it. This is pretty gross. Yes, whenever you flush the toilet there is a mist that comes from the final flush. If you don't believe me, stick your face down in the bowl and flush away. The mist does carry coliform bacteria. If you are a guy and have never had a wee bit of (how shall I say) wee splash back on your from the toilet I congratulate you. But I doubt it. Gravity, and the force of the urine leaving the body via contraction, is more than enough energy to splash back on you. Also, there are secondary effects that'll cause a liquid to splash back higher than the distance dropped (constructive/destructive wave formation) Lay out some water sensitive paper around the toilet for some distance (rice paper, tissue wrapping paper, etc) and whiz away for a day. If you like, feel free to place some of this paper on the lid of your toilet seat and pee away your day. "Your" bathroom "air" may not make "you" sick. However, I imagine that your poop stinks as bad as everyone else. It ain't ice cream, and there is a reason why waste is concentrated in one room of a house. Stick to the sprouts in a jar. Throw the water out on some plants outside.

wiley coyote (author)Calorie2008-11-20

Points well taken and all are legitimate concerns. We must agree to disagree on the grossness, at least on it being contained to the bathroom. I would like to point out that the sprouts are grown in an enclosed chamber (except for the small holes in the bottom), within another chamber, the funnel. The only open space is the drainage holes. Based on your statements, however, I'm tempted to move my toothbrush to another room.

cfishy (author)wiley coyote2008-12-01

This is by far my favorite instructable! I, too, am too rational to believe there's anything gross about it.

wiley coyote (author)cfishy2008-12-01

Thanks. "Grossness" is a relative and personal thing and as long as I'm willing to drink the tap water.....

Calorie (author)wiley coyote2008-11-20

Actually, I keep my toothbrush away from the sink. How many people do you know just splash water on their hands after relieving themselves and then slosh on over to the door? It's nasty. I would say that growing sprouts in a bathroom has a miniscule decrease in our consumption of fuels, etc. If that is a concern, bike to the store once every two months. You'll still be well over any benefits you may have gained by this sprout method.

wiley coyote (author)Calorie2008-11-24

Far too many! And the water is up so high that it slashes EVERYWHERE! Trust me, I am fully aware of the CRAP that is out there and I do find many things "apparently" far more disgusting than some. Some of the things people ingest unwittingly and willingly is "interesting" to say the least. We agree on the potential pathogens, but we are looking at it from different angles. Then again, I also think that LYSOL is EVIL and COUNTER PRODUCTIVE when used unnecessarily......... and that's about 99.9% EVIL when I do the math.

I also agree 110% about the idea not being that "green" minded. I was bored and plotting future LAZINESS!

sound91 (author)wiley coyote2008-11-20

Myth Busters did an experiment once on fecal matter in the bathroom. They placed two tooth brushes in the bathroom and two in the kitchen under a glass bowl. After two weeks of these tooth brushes scrubbing separate pieces of glass, they both had the same amount of fecal matter on them. It doesn't matter where you put your tooth brush because fecal matter is in the air everywhere. I still wouldn't grow my food in the bathroom.

Calorie (author)sound912008-11-20

I saw that one too. Remember, it's entertainment. The kitchen sponge is chock full of bacteria and decaying food. That's far more relevant. The methods they used are suspect, particularly how they sampled the bacteria on the brush. Bacterial growth is exponential as long as the food/medium available is inexhaustible. However, in the real world bacteria will eventually stop reproducing as fast. If you let either of their samples grow too long, you'll end up with apparently matched growth rates because they will both reach as much growth as is possible in a petri dish/beaker. Their can be a million reasons as to why they got the result they did. Statistically, a two by two sample of toothbrush exposure isn't useful information. And you are indeed correct. Coliform bacteria are everywhere. The issue is how much per area. There is a certain concentration that is deemed unsafe. Below that things are generally OK to consume. Also, there are variants of coliforms that are very pathogenic relative to the usual ones in the environment. That's what you'll hear about when ground beef is recalled from the stores. There is coliform found in ground beef (yes, that is cow crap) in some amount. The problem is when certain types of coliform bacteria are included in the mix. The different bacteria has a wee bit different piece of DNA that causes it to make a susbstance that is very toxic. This toxin causes all sort of problems, usually a very nasty food poisoning. It can also cause kidney failure. You should always cook your ground beef to well for this reason alone. You really can't kill the "superbad" bacteria so heed any recall warnings. *** There was a Showtime series called Bullsh*t by Penn and Teller (the magician fame). One episode they took it upon themselves to dispel some hygiene "myths." I have to tell you everyone in my field moaned. Again, it was entertainment at its worse. The highlight of that show was swabbing different individuals buts to check if they are full of bacteria. The results came out in their favor. A neighbor of mine forced me to watch it. He was very impressed with himself that he had learned something about science. My response was straightforward. Let me fart on your dinner tonight. Right now. And I'll swab my rear in the same areas with your silverware that they swabbed on TV. He declined, and I felt that my point was well made. There's a reason why we have a strong aversion to biological waste in our society.

wiley coyote (author)sound912008-11-20

My point exactly. I'm still more worried about my fingers. I do understand why people wouldn't and I respect that. I do have a healthy respect of germs and there are many bathrooms in which I would NOT do this either. I keep mine relatively clean and I just don't find this particularly dangerous, relatively speaking, compared to a lot of the other "fresh" crap people buy everyday. I WILL post if I get sick from this in any way, I promise.

foobear (author)2008-11-21

guess I have no clue. why do we need to flush water through bean sprouts?

wiley coyote (author)foobear2008-11-21

The rinsing allows them to sprout without drowning or drying out. Normally people sprout them in a jar, by rinsing them a couple times a day, for three to four days, and allowing them to drain between rinsing.

explosivemaker (author)2008-11-18

now there's some green thinking....thumbs up

Thanks, but I'd have to chalk it up to insatiable curiosity mixed with absolute lack of commitment and a sprinkle of cheapness. It's so sad when so many die. You can feel it in the force, you know. that one eyed weird look and slowly stepping away.....

Sorry, I was referring to all the sprouts that have died at my hands due to my lack of commitment to routine rinsing. It made sense......... sort of........ before I added the cheapness bit.

That's hilarious!!!!! Don't forget to wash your hands.

jeff-o (author)2008-11-18

Very clever! I've always wanted to try my hand at hydroponics, but knew that I'd probably be too lazy to flush the system on an ongoing basis. Now you've got me thinking about where I can tap into my house's water supply to make the process completely automatic!

wiley coyote (author)jeff-o2008-11-18

If it it a closed loop back into the water supply, you won't be able to add nutrient and anything after the "system" would be contaminated, it would also be under pressure, but with proper placement............. If it drains into an actual drain, you could add nutrient and grow anything... almost . I wouldn't recommend adding any nutrient to a toilet tank. Yard irrigation systems would make for very easy integration at a reasonable price. Everything you need is at your local renovation/garden centre... Home Depot for me. I recommend avoiding the sales clerk unless they know the systems well. There's a lot of stuff you wouldn't require, but they'd love to sell you. Laziness is the stepmother of invention!

jeff-o (author)wiley coyote2008-11-18

Hmmm, and I guess the hard water wouldn't provide quite enough nutrients to the plant, eh? I was thinking of a neat little unit that taps into the water supply line before it reaches the toilet. Water would continuously wash over the system, then end up in the toilet as "grey water." But of course, you run into trouble keeping everything pressurized so that the water can actually get to the toilet!

wiley coyote (author)jeff-o2008-11-18

Hard water, eh? Sounds like extra minerals. Hope their tasty and healthy ones. As for adequate levels for life and such, I have no idea, but trying it would probably give you a good idea. I would imagine that something would definitely be lacking. I would treat it like a supplement for the plants. If you figure it out, I'd like to see it.

jeff-o (author)wiley coyote2008-11-18

Yep, hard water is whatever comes into your house from city water lines. It's basically a few harmless minerals, a bit of calcium and magnesium mostly. Probably not enough for the poor plants to thrive on.

dchall8 (author)2008-11-18

This is very clever. I like it. But why is my daughter turning up her nose? I always sprouted seeds starting with a 1 full day soak and then the daily rinse. I suppose the soak could be done in a jar first and then drop them into your system. Or maybe the soak isn't needed. Have you tried radish seed? They're spicy! As you already know, look for them in bulk, not at the garden center.

wiley coyote (author)dchall82008-11-18

I can't figure out why, they don't smell bad....... lol. Here's a test, buy a bag o' sprouts and grow some, even the standard way, just do it in the bathroom. On harvest day, open the bag and take a whiff and a feel. Stick em in your mouth without rinsing them, go ahead.... I dare you. Then...... do the same with your freshly grown, you will not hesitate sticking these in your mouth at all.... at least not the second time, once your mind is opened. It's in the openness of the tank that gets people the most ..... I think. Like meat, people really don't want to know. The sense of disgust and contamination is often exaggerated in both directions. I've thought about housing it in a nice, pretty, white wall cabinet. This would "isolate" it visually and would close off the top of the tank. I bet a piece of wood across the top, with the funnel draining through a hole in it, would have quite an effect in perception. Perception in everything. I've never sprouted radish, but have eaten them during previous hydroponics experiments, and they are DELICIOUS. Thanks for reminding me. I may just add the TEES back in and expand it to three chambers again. There's plenty of water for this, for me at least. I was growing them in tandom, so I never ran out, but it was too much. Another tasty salad crop would be just the incentive I need to get healthier. I will look into others as well. Thanks

dchall8 (author)wiley coyote2008-11-18

I don't have any problem with this project. My wife has my kids spooked about "toilet water." It doesn't seem to sink in when I explain the water in the back is tap water. Of course the sediment in the tank doesn't help but it is drinkable water - especially the fresh watering coming in with each flush - can't get any cleaner.

wiley coyote (author)dchall82008-11-18

Sounds like more sprouts for you! Let the nay sayers labour for their own food. APPARENTLY it will taste better. Show them any hard water scale or kettle and you can explain the non slimy stuff away. Actually the inside of your tank is probably sqeeeeeeaky clean. I had to actually drink a glass from it to prove my point. I'll admit, I was a little worried at that point, but I also know that worse things are still on my fingers at any given time.

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