Hey there fellow plant lovers! I’ve been intrigued with a closed plant terrarium for a while now. How cool is it to have plants in a completely shut jar, not needing fresh air, water or new soil? That’s a dream for people who struggle with keeping plants alive (like me). So since I’m always in for trying something new and nerdy, I did my research. I built these three beauties over a month ago and the big ones are doing great. The smaller terrarium was more of an experiment with some plants from my neighbourhoud, so I wasn’t sure if they would like the humid circumstances in the terrarium. They did not. So be warned and don’t use some random plants lying around your house. These jars make my dormroom feel like a 19th century biologist’s lab. You know the ones with drawings of all kind of insects and foreign creatures on their walls. And I love it.
I will give you some tips about what kind of plants do like humidity (spoiler alert: don’t use a cactus or succulent) and how to layer your base.
To make a Closed Plant Terrarium, you need:
- An air thight jar (I would recommend my big jar of 5 litres for €11,99, find it here)
- Some cute plants (the Spathiphyllum I used, is available in most plant shops or florists and costs around €3)
- Moss (just grab some from your garden or local park)
- Potting Soil
- Pebbles (for a layer of two to three fingers)
- Activated charcoal (just enough for a small layer, I bought this at a aquarium shop)
- Mesh (in a circle to cover the pebble layer)
Plants you can use:
Ferns such as Phlebodium or Adiantum,
The small Calathea,
Carnivorous plants such as Dionaea muscipula
Clean the jar and make sure it is completely air tight. Otherwise the water will evaporate and your plants will not be happy. Grab your pebbles and pour a layer of one to two fingers in your jar. This drainage layer ensures excess water doesn’t stay in the soil and causes root rot.
Now cut a round piece of mesh that’s a little bit bigger than the diameter of your jar. Use this to cover the pebble layer. This is important, since you don’t want the soil and active coal to sink into your pebbles.
For our next step, use your activated charcoal. The charcoal helps to remove toxins and odors. You don’t have to use a lot (I used way too much, oops), just enough to cover the mesh layer.
Add the potting soil on top of the activated charcoal. Make sure this is enough, so your plants will be able to grow roots.
This is the fun part! Remove your plant from the container and brush off the loose soil around the roots. Put your big plants in the soil first (dig a little hole for the roots) and add smaller plants or moss later. Make sure you like your composition and check if your plants have enough space. Maybe add some wood or rocks for extra detail.
Last but not least, add some water to the jar. Use just enough to wet the soil. You should leave the jar open for a few days to allow air to circulate around the plants, but I didn’t do that (I’m wild, I know). After a couple of days, close the lid and watch it grow!
Terraria love indirect, natural lighting. Don’t place these babies in direct sunlight or other hot spots. You don’t want to burn or cook the plants. You can open the jar from time to time, to allow some fresh air in there. I open mine once a month for a few seconds (because I’m too curious). But if you’re terrarium’s in balance, you don’t have to open it at all. If your plants grow to big, just trim them a bit. The jar should be a bit condensed all the time.
Have fun with it! I hope your little closed plant terrarium will be happy for years and years.