D.I.Y. Terrarium: Science in a Glass Case


These are terrariums.


This is a nerd.

Nerd + Terrarium = Nerdarium!

Now we’re not talking about sprouts in a cup. We’re talking about using our nerdy obsessive tendencies to creating a tiny universe unto itself. Muahaha!

It doesn’t actually take an omnipotent green thumb to create your own little ecosystem. Terrariums are easy to put together, materials aren’t hard to come by and with a little geeking out, you could have yourself a pretty badass terrarium.


Terrariums are, at their core, a clever way to get a child to do a science project that doesn’t leave your kitchen looking like the site of an epic baking soda/red food coloring battle. You know — the whole science fair volcano fail.

Power-hungry universe-ruling aspirations aside, terrariums really are little self-sustaining ecosystems. Making a terrarium with the kids is just a much cooler way to teach them about ecology and the inter-connectedness of creatures and the planet.




Open Terr

This can be anything from a container made specifically for terrariums to an old fishbowl. First decide if you want an open terrarium (above) or a closed terrarium then go nuts.

You can use a light bulb, a mason jar, a vase. You can even use the tincture bottle from your collection of pre-1930s apothecary antiques! You know, whatever you have lying around.

Mason jar


Sand: Nothing special here, just the stuff that comes from a beach or a sandbox. Activated Charcoal: Available at aquarium supply stores. Potting Soil: This should be a mix of regular potting soil and a well-draining potting soil like one designed for succulents. Pebbles: Feel free to take care of this one at the aquarium supply/pet store, too. Pebbles that go on the bottom of a fish tank work great.

Damp Spaghnum Moss

This is optional, but it helps keep the soil from falling below the pebbles. It also looks pretty cool, especially if you’re going for a hobbit-like shire-esque vibe.


PLant 1

Variegated Spider Fern

Your best bet for plants are ones that work well in a high-humidity environment. This is mostly true if you want a closed terrarium. I like these for both types of terrariums though because these plants are hearty and hard to kill, which is nice if your little gardener’s thumb is more brown than green.

Star fish

Starfish plant (Cryptanthus Bivittatus)

Venus flytraps and other carnivorous plants are also a lot of fun. (If you have a kid who doesn’t find plants quite as thrilling as you do, this is the way to go.) Warning: These can be a little bit more finicky than the others on this list.

Spray Bottle or Mister

Even though the inhabitants of terrariums won’t need much, I hear all plants enjoy water from time to time. This might take some trial and error on your part to get the right amount, but the wise people at your local nursery can help you learn how much water your plants need.


OK, moss is fun on its own but when creating a terrarium with kids you might want to think about adding some friends.


Also particularly amenable to living in a terrarium are Kai, Chewbacca and Jake and Lumpy Space Princess. This is where to let your little nerd go crazy.


  1. Start with a 1-inch thick layer of pebbles in the bottom of the container.
  2. Put a layer of activated charcoal on top of the pebbles approximately one-half inch thick. This will filter the water.
  3. Put a layer of Sphagnum moss on top of the charcoal.
  4. Top these layers off with a 2- to 3-inch thick layer of soil.
  5. Poke small holes into the soil and transplant your plants or place seeds into the container. Take some time with the kids to talk about the design of the terrarium and how much space each plant might need.
  6. Place any buddies, dinos, Yodas or toy butterflies in the container.
  7. Water in moderation and cover. Keep an eye on it. If it needs more water, then add. If you have over-waterers in your house (like I do), you may notice the soil is getting too moist. If this is the case, remove the lid from a closed terrarium to let it dry a bit. If you have an open terrarium, teach your little gardeners that water doesn’t always equal love. Over-watering your terrarium can lead to mold growth, and that’s a whole different and smellier science project you probably don’t want to deal with.

There are guides and kits complete with all the necessary materials. Oh and I feel it’s my duty to let you know that this exists.



Just because I want to teach my kids about biology doesn’t necessarily mean that I was paying attention in bio class when it was being taught to me. So for others of you who may have been checking out fellow students instead of checking on the Erlenmeyer flask, here’s a quick rundown of the science-y part of terrariums.

The ecosystem inside your container is a microcosm of the real world. You cause it to “rain” by watering the plants or seedlings. The water is accumulated in the soil and sunlight will cause this water to evaporate and form droplets along the sides and top of the container (condensation). These drops will grow larger, then fall back into the soil. This is a cyclical process (the hydraulic cycle) that will keep going as long as there is water and sunlight. This process is what gives the plants a constant supply of moisture and nutrients. It’s also known as a closed-loop system. The activated charcoal in your terrarium acts like a filter. As the water passes through the charcoal impurities are trapped so the water stays clean for the next cycle.

Terrariums also provide opportunities to talk about what pollution does to the cycle, other closed systems and bio-regions. For instance, when recreating Tatooine so your LEGO Luke Skywalker can feel at home, be sure to remember that after the Rakata razed the planet, drying up its riverbeds and boiling away its oceans, the planet took on the characteristics of a desert ecosystem. Whereas when Luke is on the planet Hoth that’s more of an Arctic Tundra situation.


These miniature versions of ecosystems can teach budding naturalists a lot about the real world, even if what’s in the mason jar is from Middle-earth or Narnia. Or elsewhere …


  1. Jade Horse

    A good post, but you have shown a picture of succulents in a closed jar- they will quickly go mouldy, blacken and die. They’re drought-hardy plants, and that much humidity will kill them.

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