Common Terrarium Mistakes and How to Avoid Them

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People often make common mistakes when creating their terrariums, which can lead to the death of their plants. These mistakes can be easily avoided with a little bit of knowledge and preparation.

By reading this guide, you'll learn how to avoid the most common terrarium mistakes so that your plants thrive and flourish inside their home. 

What is a Terrarium Plant?

Terrariums are plants that enable you to grow plants without soil or in a soil-less environment. Terrarium enables you to design and create bantam ecosystems of little plants and other cosmetic elements inside a glass enclosure. Terrariums bring contained, natural elements to your home or office and can last for several years with proper care. 

Terrarium Plant
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You can think of terrariums as an enclosed garden such as a fishbowl, but instead of housing fish, they house plants and other organisms like mosses and mushrooms. 

Common Terrarium Mistakes

Choosing the Wrong Plants

Not all plants make good terrarium plants. You should only choose small plants and be able to thrive in a closed environment where they will be deprived of light and natural conditions. Succulents, mosses, ferns, and tiny cacti are good candidates for a mini-ecosystem such as this one.

While it's possible to grow almost anything in a terrarium, choosing plants that will thrive in the terrarium you're creating is important. If you're designing a closed terrarium, select plants that prefer a moist environment. Also, make sure to combine plants with the same light requirements. Low light plants generally work best.

Too Much Light

Most plants that are suitable for terrariums do not require extremely bright light. If placed in direct sun or extremely bright light, terrarium glass can act as a magnifier and burn the plants.

Temperatures inside the terrarium can rise promptly, and before you know it, the terrarium can become as steamy as a sauna. Most plants can't tolerate this kind of heat, so it's best to keep terrariums out of the direct sun.

Too Little Light

Although most terrarium plants need bright light (but not direct sun), the plants will become lanky and begin to stretch for more sun if kept in a dark locationight. Most plants need at least some light to survive.  If you've ever seen your cacti or succulents “reach” toward the window, chances are they need more indirect light.

If your terrarium is not receiving enough indirect light, use glow lights or fluorescent lights to provide supplemental light or place the terrarium closer to a window that receives good but indirect light.

Over Watering

If the soil is kept wet for extended periods of time, the water can begin to pool in the bottom of your terrarium.  This will cause root rot and eventually kill the plants. Make sure to only water when the soil feels dry. It's easy to over water terrariums. Too much moisture is present in the terrarium into the daylight hours, so try to open the plant for a few hours for condensation to dissipate.

One way to prevent over watering is to use a spray bottle instead of a watering can. Absorb any extra water with a paper towel if you do over water. Leave the top off of your terrarium until it has dried out.

Over Fertilizing

Most terrarium plants do not need to be fertilized. You want to keep your terrarium plants small and inhibit their growth, so don't feed them because the plant will quickly outgrow their confined space.

Dirty Glass

Leaving the top on your terrarium for weeks will allow it to get dirty and inhibit airflow. If you need to leave your terrarium closed up, clean the glass with some water and vinegar or window cleaner once every week or two. If the glass is too dirty or foggy, it will be difficult for light to reach your plants.

Use a damp piece of newsprint or a lint-free cloth. Do not use any harsh cleaning products on the inside of the terrarium because the chemicals in the cleaning products could harm your plants. While cleaning the glass, don’t forget the leaves. Learn some best ways to clean household leaves before you do it.

Failure to Remove Dying Plants

When a plant has become too large for the space it's been allotted and is beginning to die, you must remove it before its decaying process can affect your other plants. When plucking out the dead foliage, be gentle so as not to disturb any nearby live leaves.

Failure to Remove Dying Plants
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Use a small shovel, terrarium tool, chopsticks, or long spoon to remove the plant. Be careful not to disturb the roots of other plants. Replace the plant with one of a similar size and the same moisture and light requirements. Be sure to surround the roots with soil, leaving no air pockets.

Too Close to Heat Sources

The heat generated by a radiator or heating vent can kill your plants quickly. If you place your terrarium on or near a radiator or other heat source, most terrarium plants won't survive. In tight quarters, you might put it near one of those sneaky heat sources if you're not careful.

Planting Succulents in Closed Terrariums

Succulents do not require high humidity levels. They thrive in high light and low moisture environments. Because closed terrariums trap moisture inside, succulents can rot or suffer root rot in these conditions.

If you're using a closed container with succulents or cacti, be sure to open it for several hours each day to allow fresh air to circulate and release excess moisture. Note that even a large jar will be too humid, airflow is important and air must be able to circulate around succulents.

Overgrown Plants

Plants that are too large won't thrive in a terrarium. Larger plants often have trouble remaining upright and may require staking, so they should be planted outside of the container. When planting succulents in closed containers indoors, always remember to use small-sized varieties which will not grow up or out of their space. Don't let your terrarium plants to become leggy and overgrown.

Overgrown Plants
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You want to be able to admire individual plants and see the other decorative elements inside the terrarium. To keep your terrarium plant neat and tidy, trim it when it becomes overgrown and has crowded the terrarium. You can also prune their roots to keep them small.

FAQs on Common Terrarium Mistakes and How to Avoid Them

How do you maintain a terrarium?

For moss terrariums, they need light water once a week. For plant heavy terrariums, water them twice a week. Use a terrarium gun or a terrarium water bottle with a pointy nozzle to help guide the water. Make sure your terrarium isn't in direct sunlight to avoid the plant overheating and drying out. 

What are the components of a terrarium?

A terrarium has four main layers. These include gravel, moss, soil, and decorative layer. You can use your terrarium different plants as long as you keep the humidity levels are high and the water stress on the leaves are reduced.

Final Thought on Common Terrarium Mistakes and How to Avoid Them

As you can see, terrariums are low maintenance and ask less attention than most other house plants. However, they do require episodic care, and to maintain a healthy environment for your plants, try to avoid the common mistakes listed above.


Kristina Perrin

Kristina Perrin

Kristina is an expert DIY home remodeler and mom to three. When she's not cooking or experimenting with new recipes, you can find her working on new home improvement projects or writing about her favorite kitchen appliances or DIY projects on Kitchen Infinity blog.

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