The Ultimate Closed Terrarium Care Guide

A closed terrarium can be a stunning addition to your home, providing both beauty and functionality. With some careful attention, these plants can thrive for years to come.
A two closed terrarium.

Closed terrariums, also known as gardens under glass, provide a unique design while creating tiny eco-systems of attractive plants and other decorative elements in a transparent glass enclosure. Terrariums play a critical role in bringing nature indoors, and if taken care of properly, they can provide you with a beautiful indoor landscape for many years. And what is even more interesting is the fact that most of them are low-maintenance and require less attention to thrive compared to other houseplants.

So, how do you take care of your closed terrarium? Closed terrariums will do best when positioned in good natural light rooms with an average temperature of 20 degrees Celsius. If your terrarium looks wet and foggy, open the lid for a couple of hours until the visible fog clears. Monitor it closely for any signs of mold or fungi, and check for humidity levels. If it looks dry, use a spray bottle to mist the plants and soil lightly. Open the windows and doors of the room where you have positioned your closed terrarium during winter to prevent excessive humidity. In terms of water, most closed terrariums only require occasional light misting and should never be overly watered since it can cause root rot or mold growth.

This blog post discusses key tips and tricks for caring for your closed terrarium. Read on to find out everything you need to know.

How Do Closed Terrariums Work?

Before diving into how to care for your closed terrarium, it is crucial to understand the science behind how they work. Understanding how the eco-system works will help you maintain it properly.

Closed terrariums are self-contained ecosystems that rely on the water cycle, photosynthesis, and respiration by their inhabitants to keep them healthy and thriving.

The inside of the glass enclosure creates a moist environment in which humidity levels are higher, and temperatures are warmer than the surrounding air.

This allows moisture to condense, form droplets, and collect on the walls of the glass enclosure, which then filter back into the soil, providing water for the plants.

Closed terrariums also benefit from the transpiration of plants, which involves releasing water vapor into the air. The water vapor plays a critical role in maintaining humidity levels inside the terrarium.

Plant on a closed terrarium near the window.
Understanding how the eco-system works will help you maintain it properly.

The soil within the terrarium plays a critical role in supporting healthy microbial processes that nourish the plants. Moisture from plant transpiration and evaporation recirculates in the terrarium as “rain“, keeping the soil moist.

The terrarium is designed to absorb small changes that help it to maintain a healthy balance.

However, nature takes care of most of the issues in a closed terrarium. The ecology isn’t complete on its own since it requires light and occasional watering to keep the plants in great shape.

What Plants Do Well in a Closed Terrarium?

The plants you choose to put in your closed terrarium will determine the success of your little ecosystem.

Generally, ferns and other moisture-loving houseplants are great for a closed terrarium since they thrive in more humid environments. Small succulents and cacti also do well in a closed terrarium as long as they are not overwatered.

You can also go for trendy plants such as Baby Tears, Pilea, and Peperomias. Exotic epiphytes and low-growing nerve plants are good choices as well.

A woman smiling while holding a closed terrarium.
It is also essential to select plants of similar sizes so that the enclosure does not become overcrowded.

When selecting plants for your closed terrarium, ensure they are compatible with the environment.

Research each plant you are considering and consider whether it can survive in a more humid environment. It is also essential to select plants of similar sizes so that the enclosure does not become overcrowded.

Key Closed Terrarium Care Tips

Now that you understand how closed terrariums work and which plants are suitable, it is time to learn how to maintain them. Here are some tips for keeping your terrarium in good condition:

Watch Your Watering

Close terrarium plants are highly sensitive to excess water. In fact, overwatering them is riskier than underwatering. It is relatively easy to overwater your closed terrarium but quite challenging to fix the damage that follows.

Therefore, it is good to understand your terrarium’s watering needs and only add water at the right time. Use a spray bottle or mister to water your plants as evenly as possible.

The presence of heavy condensation on the glass wall is a vital sign of overwatering, but it is not the only one.

A jar converted to a closed terrarium.
Overwatering them is riskier than underwatering.

Keep in mind that your soil should never be saturated. Your plants only need a light misting to thrive. If the soil appears dark and wet, open up your terrarium and let it dry before things get out of hand.

Although the individual care of your closed terrarium plant will mostly depend on the plant species you have, it is relatively safe to maintain consistent light moisture for better results.

If you use a drainage layer, check how full it is. Ideally, you should have no water pooling in there. If there is water, you need to open your terrarium and let it evaporate.

Provide Adequate Light

Since closed terrariums are mostly lightproof, they require artificial light for plants to grow.

Depending on where it is placed, you may want to get a small LED lamp or a fluorescent light that provides enough illumination.

LED lights are the ideal choice since they do not generate too much heat that can damage your plants’ delicate environment. Also, you need to keep the light on for about 8-10 hours a day for better growth.

Watch Out for Signs of Mold

Mold is the biggest enemy when it comes to taking care of your closed terrarium. Mold tends to thrive in relatively hot and humid environments. It only takes a couple of weeks for it to ruin your beautiful environment.

However, a single mold spot in your closed terrarium doesn’t spell a disaster because mold is part of a natural decomposition cycle.

A woman brushing the plant in a Terrarium.
It is always good to tackle the mold at its source.

The spot will always disappear after a couple of weeks, and everything will be fine. Getting some air into your terrarium can hasten the process.

You can also deal with small patches of mold using a Q-tip and hydrogen peroxide. All you need to do is wipe off the patches, and you are good to go. It is always good to tackle the mold at its source.

Monitor Temperature and Humidity Levels

The temperature and humidity levels in your closed terrarium should be closely monitored. The ideal temperature range for terrariums is between 70 and 80 degrees Fahrenheit.

You can monitor the humidity levels with a hygrometer or by feeling the soil with your finger. If it feels cold and wet, you are probably good to go. You should also aim to keep the humidity level between 40 and 60 percent.

If the humidity level gets too low, you can increase it by adding a light mist of water or simply placing a wet sponge in the terrarium.

Provide Ventilation

Ventilation isn’t a big issue with closed terrariums since the air that plants produce is automatically recycled in the ecosystem. Typically, plants produce oxygen during the daytime but consume it at night.

However, the balance isn’t perfect, and you need to intervene to keep things in check. Consider opening your terrarium for a couple of hours every two or three weeks to keep the ecosystem fresh.

This is also the perfect time for other routine maintenance tasks. Once you are done with everything and put the lid back, check the rate at which condensation forms on the glass wall.

If you don’t see any signs of condensation after a couple of days, consider misting your plants to restore balance.

Should I Prune My Closed Terrarium Plants?

Most closed terrarium plants are relatively easy to care for since they grow slowly in limited conditions. Pruning is a must-do task that keeps your terrarium looking healthy and attractive.

However, you must inspect your plants objectively before you decide to prune them. Some plants may require selective pruning of some of their leaves and branches to get rid of dead or dying foliage.

A african violet plant in a terrarium exposed to sunlight.
Pay close attention to how much light each plant receives.

Furthermore, you must appreciate the fact that your plants grow at different rates. Therefore, you will be pruning each plant at different times.

Pay close attention to how much light each plant receives. The primary objective is to ensure no plant puts out leaves that block others from receiving their fair share of light.

You should also consider pruning leaves and branches that have started touching the glass wall. These leaves attract condensation and are more prone to fungal and mold issues.

Choose Appropriate Plant Sizes

It is also essential to select plants of similar sizes so that the enclosure does not become overcrowded.

If your closed terrarium is too small, you should opt for miniature plants that only require a little space, like mosses and ferns.

Final Thoughts

Closed terrariums are a great way to bring nature indoors and create a unique living environment. They look beautiful and provide numerous benefits, including better air quality, lower stress levels, and improved concentration.

Caring for your closed terrarium is essential to maintain its beauty and ensure the health of your plants. Ensure you monitor temperature, humidity, and ventilation and always keep an eye on signs of mold buildup.

Also, select appropriate plant sizes so your terrarium won’t become overcrowded. You can always have a beautiful, closed terrarium with a little effort and care.

Last update on 2023-10-05 / Affiliate links / Images from Amazon Product Advertising API

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