How to Build Your Own Wunder-rarium

Weather Underground Staff
Published: July 25,2016

Terrariums are fun to build with kids, not to mention educational, teaching them about the Earth’s water cycle and how it can sustain plants in an enclosed environment. They’re mini worlds which can illustrate how our world works. They also happen to be self sufficient and provide a great focal point in your home or office.

  
































There are two types of terrariums, sealed and open. Open terrariums are best for dry, weather-loving plants because they lose water vapor, creating an arid environment. Sealed terrariums create a very humid environment and can sustain themselves by creating their own water cycle.

The water cycle is the process of water evaporating from Earth to create water vapor and clouds, then condensing in the atmosphere to create precipitation (rain and snow), which falls onto the land and ocean to complete the cycle. Water never leaves the Earth system -- it just takes on different forms (ice, liquid, water vapor) as it moves around. A closed terrarium works in much the same way. Sunlight enters through the glass and warms up the environment, which helps the moisture from the soil evaporate. The water vapor condenses on the interior surface of the terrarium and creates precipitation which then falls back onto the plants and soil. The clear glass gives the plants access to sunlight, which facilitates photosynthesis to encourage growth.

Finding the right amount of light for your terrarium is important. If you have it in too sunny of a location the inside will be too hot for the plants, but if there isn’t enough sunlight it won’t encourage evaporation which is needed for the water cycle.

Building a Closed Terrarium

Materials

• Clear glass or plastic container with lid (you can make a terrarium any size, it depends on your plants.)
• Ferns, moss rocks and stones as filler and drainage
• Activated charcoal (You can get this at a local aquarium shop)
• Potting soil
• Decorative stones, moss and animals

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Start your Mini World

To create your own closed terrarium start with a clear glass or plastic jar with a lid. If you don’t have a lid you can use plastic wrap on the top to catch the moisture. Make sure the lid is removable--terrariums can be self sufficient but you may need to water your plants if they appear dry or open the container if there’s too much moisture. We used a glass drink dispenser and put a plastic tube through the hole in the bottom. This isn’t a necessary step for the terrarium, but you’ll see why we did it if you read through!

 

Make the Ground

After you’ve got your container, fill the bottom with rocks or stones, around an inch depending on your container. This will act as the drainage for the plants so the roots don’t stand in water. Next add a layer of your activated charcoal; this helps keep your terrarium fresh, healthy and mold-free. Now add a layer of dirt on top. You can add more rocks for visual interest at this point, too. The rule you want to adhere to is that the stones and soil fill a third of your container.This makes sure you have enough drainage and soil for your plants.

Let’s get Planting

Take your ferns and decide the placement before putting them in. Try to make sure the taller plants are in the back and shorter in the front. Remember that the plants will grow so leave some breathing room for them. Start with your largest plant, start by making a well in your dirt for where you want the plant to be. Remove the plant from the pot and put it in the well in the soil, use some more soil and check that it’s secure. Make sure the leaves aren’t touching the edge of the container, that can trap moisture and cause the leaf to rot or mold. Go ahead and plant the rest of your plants finishing with your smallest. Remember to leave space if you want to add any decorative elements! You can use a paint brush to get any loose dirt off the leaves when you’re done.

Decorate!

Use fun stones and moss to fill in the spaces between your plants to finish the landscape. You can use decorative artificial moss to ensure some lasting color. Grab some fun plastic creatures to put some life into your mini world. We used some rainforest toys to add to our terrarium. At this point you can seal off your terrarium and voilà! You’ve just created your own living world!

You can observe your mini-world and watch the water cycle in action. After a few days, you should start seeing condensation on the glass, indicating your terrarium’s water cycle has started. If you want to get a little high-tech, you can move on to the next (optional) step.

Get the Data

Of course a terrarium from Weather Underground wouldn’t be complete without its own personal weather station (PWS)! Our resident PWS master built a mini weather station so we could record the humidity and temperature of our Wunder-rarium.

That plastic tube, if you remember from the beginning, is for the USB cable used to power the weather station. You can also use batteries but you will occasionally have to take the station out of the terrarium to charge the battery. Take a look at the full instructions for a DIY mini-PWS.

Helpful Tips

• If your plants look dry, open your container and spray the plants.
• If there’s too much condensation and your terrarium looks foggy, open your container for a few hours to allow some of the moisture out.
• Occasionally prune your plants to promote growth, also prune back any dead looking or rotten leaves.
• Make your terrarium festive! Add different decorations to make your terrarium suited for every season.