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 .
Step 1: Stuff You Need
- Magnets (I used 8x3mm ones. I could only find 1/4 x 1/16 inch ones on amazon.com. If you are in no hurry you can get 8x3mm ones on ebay.com 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 amazon.com) and 50% Perlite (e.g. on amazon.com))
- 5 mm thick cotton thread
- 3D printer
Step 2: Brick Block
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
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
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
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
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!