Self-Watering Mario Planters





Introduction: Self-Watering Mario Planters

About: Hi, my name is Britt Michelsen, I'm a Chemical Engineer especially interested in Computational Fluid Dynamics. To balance all the theoretical work I like to make stuff in my free time.

In this instructable I am going to show you, how to make self-watering Mario planters, paired with fun magnetic building blocks.

In 2010 I build a planter for my carnivorous plants out of wooden blocks:

Sadly, even though I coated the inside with a thick layer of paint, the wood has started to mould because of the watering water. So now that I have an awesome 3D printer thanks to instructables I decided to build a new version.

Btw. don't worry, if you don't have a 3D printer. I am sure that you can build all the elements out of wooden blocks, craft foam, tubes and store bought figures. Or you can build my older version, just remember to properly coat the inside.

In case you are interested in the science of the self-watering planters, this is how they work:
Like most self-watering planters, this one works due to capillary forces. The cotton or wool thread we are going to use consist of many thin hairs and therefore a lot of thin channels in which adhesion and cohesion forces occur. Note that the bigger the specific surface area compared to the volume is, the bigger the resulting capillary forces are going to be. Btw. this is the same effect, that prevents the paint or water from immediately dripping from your paintbrush or the reason why trees can't get bigger than 130 meters: After 130 m the strength of the osmotic pressure and the capillary forces are not big enough to overcome gravity [1].

Step 1: Stuff You Need


  • Magnets (I used 8x3mm ones. I could only find 1/4 x 1/16 inch ones on If you are in no hurry you can get 8x3mm ones on from China) (I also used 6x1.5 mm ones for the coins)
  • Paint (For the Europeans among you, I used Revell enamel paints and am very happy with the result. The only exception are the Tubes, which I painted with Warpstone Glow from Citadel)
  • Optional: Citadel Technical: Liquid Green Stuff
  • Clear coat
  • Plastic Filament depending on your 3D printer
  • Venus flytrap
  • Carnivorous plant soil (50% Peat Moss (e.g. on and 50% Perlite (e.g. on
  • 5 mm thick cotton thread

  • 3D printer

Step 2: Brick Block

As you can see in the picture, the brick block consists of two parts. This way it is easier to attach the magnets. I have uploaded both files to this step. Download them and print them out.
Use a strong glue, to hold the magnets in place. Admittedly, that's not quite as it easy as it sound, because as long as the glue is not dry, the magnets start snapping to an other one. The best way I found to hold them in place, was to use extra magnets on the outside.
There are different ways to smooth 3D prints, but I have not seen anybody trying "Liquid Green Stuff" from citadel. So I decided to give it a shot and was really happy with the results. Though it is kind of expensive and I would not use it on bigger parts, it works great on smaller parts. I noticed, that it sticks better to the pieces, if they are first treated with a plastic primer. Afterwards I use about 3 thin layers of Liquid Green Stuff. It fills the gaps between the layers, if you want you can also sand the piece afterwards, but it is not really necessary.
I used three magnets on each side, to give the cubes some extra strength and to prevent them from turning.

Step 3: Mario

I tried modelling a Mario myself and failed miserably. Luckily user Lemonde upload an awesome version here.
You will have to print the file attached to this step and the file "BlockBottom.stl" from the last step, to build the Mario shown in the pictures. After printing the files, remove all the support structures. Once again I used the "Liquid Green Stuff" to smooth it out.

Step 4: Coin Block and Used Block

It is your choice, whether you glue the coin block close or leave it open (for example to place a coin inside). There are three different versions uploaded, named after the number of question marks on the sides. Simply print the version you like and once again paint it, as shown in the pictures.
I used 6x1.5 mm magnets for the coins. Simply place them in the slots and glue the two halves shut.
I noticed that the blocks tend to fall over, if the weight of the one on the bottom is too light. So I mixed some shredded lead with hot glue to make it heavier.

Step 5: Tube

Now onto the main part: the construction of the planter. I designed the inner tube as two parts, so that less support structures are needed. Once you are done printing it, just glue it together, as shown in the pictures.
The outer tube is meant to be two pieces. This allows an easier watering and better cleaning of the pots. Simply paint the outside, as shown in the pictures.
The rail I have uploaded is used to hold the pin with the thread in place. I could have added it to the design of the inner tube, but once again decided to print it as a separate piece, in order to need less support structures. Once you have printed it, glue it to the inner tube with the overhang facing away from the bottom.

Step 6: Venus Fly Trap

As you can see in the first picture it was really necessary to replant my Venus Flytrap. Choosing the correct soil is crucial for the survival of your plant, so please make sure that you have gotten the right mixture (I use 50% perlite mixed with 50% peat moss). If planted in normal soil it will die! It needs a soil with a very low nutritional content and a certain pH value.

Replanting the Venus fly trap is not as difficult as it might seem. Though you have to be very careful. Start by filling up the new pot with the soil. Wetting it will make your life easier. Compress the soil slightly and form a hole in the middle where the plant is going to go in.
The best way I found to get the plant out of the old pot is by gently squeezing the sides of the pot to release the soil from it, grab the plant at the rhizome (take a look the second picture) and remove it from the pot by carefully pulling it out. Clean the root of the plant by slowly swirling it in some distilled water and place it in the hole that you have dug before. Make sure that you plant the roots as deep into the soil as possible.

You will need a 20 cm long piece of thread. Fold it in half and place it over the pin, as shown in the pictures. Carefully push into the hole at the bottom of the pot. Make sure, that it stops before reaching the rhiozome. To hold it in place simply twist it around.

Hints on successfully growing Venus fly traps:
  • Use either distilled or rain water. The water from your water tap will kill it.
  • Venus fly traps love sunny and warm places, you can also plant them outside, if you want to. In the end of October it starts its winter rest in this time it still needs a lot of light, but the temperature should be between 5-10 degrees. It also needs less water, or else the roots will start to mould. Make sure, that the earth is moist, but not wet. This is a great advantage of the self watering pots, because they take care of the issue for you. Simply make sure that there is always water in the pot.
  • The best time to replant your Venus fly trap is after it is done with its winter rest. This will put the least amount of stress on the plant
  • Do not feed them!
  • Do not use fertiliser!
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    23 Discussions

    Just love this planter, exceptional work. Printed all the pieces and now sanding and prepping for paint. Question; Do you have the STL files for the frame that glues to the bottom of the inner pipe and the peg to push the string through.

    I'm totally new to 3d printing, I got a 3d printer manly for my son to play with and this as been the first set of prints we have done and they all came out great. Once painted I will post a picture. Great work!!!!!

    2 replies

    Thank you! Sorry, I completely forgot to upload them. They should be there now. I would love to see some pictures of the finished planters.

    Thanks, it's looking ok, your models are perfect I have to improve my painting skills. The tube came out great as I used Krylon for plastic spay. The brown of the brick and the yellow block came out great, I came back over with brush to add detail. At a viewing distance looks good but close up not so good. Been looking at buying a airbrush set up as I like the finished 3d printed object far better than the raw. I have mario to do which will be hand painted< I should be done in a few days so I will upload some pictures. Once again great work, love it.


    I really like your work here. I'm in the process of printing the parts right now. Everything is really larger than it seems in pictures! I have some questions though. The "1" on the coin is not centered, is this on purpose? Also I think the coins from the game are oval. Is there a specific reason why yours are circular? I can't seem to find the files for the pin and the pin holder. Could you guide me to the right direction.

    I can't wait to paint these, but I doubt I will reach the level of detail you have.

    1 reply

    Hi, you are right I didn't notice that it is not perfectly centered. I think they are round, take a look at that picture:

    They just seem to be oval, because they are always shown from the side, but feel free to design them however you like. Please post a picture when you are done. I would love to see the result.

    Your finished 3D printed parts are astounding - I ordered some of that green goop myself. I have been experimenting for some time with post-processing 3D printed objects...what's your process? And how did you apply the paint??

    3 replies

    Thank you! I noticed that it is best to use a plastic primer first, since it helps the Liquid Green Stuff to stick to the pieces. Afterwards I use about three thin layers. If you want you can sand the pieces but unless you use too much of it, it is not really necessary.
    I used a paint brush to apply the paint.

    What plastic primer do you use and how do you apply? Also, what type of paint to you use? It would be great to see your whole process of Mario from print to finishing (maybe another instructable?!). Totally amazed, thank you !

    Hi, I tried multiple different primers and they all worked great. So I guess as long as it says that it is for plastic you are good to go. I used a spray and just applied one layer.
    I am planning on doing an other instructable on different ways how to smooth PLA, but haven't gotten around to it yet.

    I love the idea of warp tubes as planters, and I like how you've included different types of interchangeable blocks. Are there magnets under Mario so he sticks to the blocks he stands on?

    Also, any chance we can see your attempt at making Mario? I like seeing 'mistakes' as much as I finished projects :D

    3 replies

    Thanks a lot! Mario is attached to the block he is standing on (to add stability). This block can however be attached to all the other blocks. I am thinking about making a few magnetic Goombas, but haven't gotten around to it yet.

    I just modelled one foot and half a leg and noticed that modelling the whole Mario would take me forever. So I decided to take a lot of pictures and use Recap, but as you can see on the picture, it didn't work very well. Especially the gaps between the base plate and leg and between the arm and face doesn't show up.

    I am currently building a better scanner, but first I need to finish the write-up for at least one of the projects I wanted to enter in the "build your lab" contest as well as a scanner for humans (to scan my family on Christmas).


    lol, I didn't realize that. I guess he isn't happy with the results either. Kudos for knowing that it is superman!

    BrittLiv, I love the idea, but I found that Venus Fly traps don't like my dry climate. In my area (central California) they are sold in a small pot with a clear plastic dome over them to increase the humidity for the plant.

    1 reply

    Ah, that's too bad. I have been growing Venus fly traps for years now and noticed that the ones under a dome actually grow worse than the ones without one. I think it might be because it is blocking the light, but I am not entirely sure.


    4 years ago

    This is a nice instructable and ill have to try it sometime. Where did you get the Venus fly traps? I've been looking for a while and can't find them anywhere.

    1 reply

    Thank you! I got mine in a gardening store. You can also get them online, e.g. here or here. If you buy them online make very sure that it says plant and not seeds. Getting it to grow from seed is really difficult and the plants are not that expensive that it would be worth the trouble.