Tips & Tricks For Caring For Terrariums

Terrariums are the next level of the indoor plant game, providing green thumbs everywhere a chance to cultivate a miniature environment right in their own home.

Though terrariums are fairly straightforward in concept, they do require a little more care and attention than most indoor plants do. On top of ensuring the plants are getting enough light and water, terrarium owners also need to keep an eye out for humidity levels, rot prevention, plant growth rate and even signs of mold.

Don't let these things detract you, though, as once you get the hang of your terrarium you will find that it's an incredibly rewarding slice of greenery that is sure to brighten up your home. To get you started, here are some terrarium care tips that you can use to troubleshoot your own terrarium or plan on how to make one for yourself! 

Terrarium care tips

Choose the right kinds of plants

The first step to ensuring your terrarium plants stay healthy and happy is to know which plants are suited for which terrariums.

Succulents, for example, are better suited to open terrariums. A closed terrarium would create an environment with too much humidity for succulents to thrive in, though that moist environment is perfect for ferns and other tropical greens.

You also want to make sure that you choose a plant that will fit in your terrarium well. A good rule of thumb is to start with plants small enough that they don't touch the sides of the terrariums — this includes plants that will grow vertically. Choose plants that will grow slowly or can be easily pruned to ensure they stay healthy in their limited space.

Signs of underwatering & overwatering

As with most indoor plants, understanding the signs of under watering and overwatering is key to keeping terrarium plants healthy. Most of the time, over-watering is a greater concern than underwatering, as excess moisture can create the perfect environment for mold and fungus to grow in an already humid and moist environment.

Closed terrariums can regulate water extremely well if the conditions are right, as long as you start with enough water in the system. A well-watered closed terrarium will have condensation on the inside of the glass during the hottest parts of the day, and the soil will have a light sheen of moisture on the top. If you're not seeing any condensation at all, or if you see any dead leaves or dry soil, you may need to add a little bit of moisture into the environment.

There is also such a thing as too much of a good thing when it comes to watering terrariums. Excessive moisture and water can cause root rot and mold, not to mention it can potentially incubate fungus gnats and other pests in the warm and moist soil. If the condensation on the inside of your terrarium features heavy droplets of water and the soil is dark and wet, then there's too much water in your terrarium and you will need to let it dry out for a while before closing it again.

Ensure proper amounts of light

Tropical plants and succulents both need a decent amount of light to grow, though they can range from requiring bright indirect light to low light and everything in between. 

The trick with terrariums, though, is that the glass acts like a magnifying glass or greenhouse, which can scorch the plants inside if they are too close to a bright light source. Alternatively, if the glass is too thick and the plants inside too dense, then your plants may also not be receiving as much light as they need to grow.

A good rule of thumb is to place your closed terrariums in bright indirect light. You can also utilize timed lighting systems to make sure your terrariums don't get more light than they need each day, or place them by a north-facing window!

Watch for mold

Mold is a natural part of the decomposition process, even in a closed terrarium. Most of the time it will not affect your plants or your mini ecosystem, as mold targets dead and decaying plants rather than your healthy ones, and it's not uncommon to see mold blooms pop up when you introduce new plants or do maintenance on your old ones. 

If the mold is bothering you or becoming more of a nuisance than you'd like it to be, then there are a few ways you can remove mold from your terrariums or prevent it from growing in the first place. 

Trim, prune & remove plants

Closed terrariums require a little more maintenance and housekeeping when it comes to maintaining plant health, especially when overgrown and dead plants are concerned.

Plants need light and water in order to grow and thrive, both of which can be compromised if a plant grows too large for its small terrarium space. Keep an eye out for plants that grow to the edge of the container or are taking over the space — also watch for plants that are getting too bushy or are growing to the top of the closed terrarium. 

Ideally, you want to keep your plants around the same size as they were when you first planted your terrarium, give or take a little bit of space. You can do this by occasionally pruning leaves or even roots to slow a plant's growth.

Finally, you want to make sure to remove any dead leaves or plants as soon as possible. Terrariums don’t have the capacity to break down dead organic matter in the same way that a forest floor does, so any dead leaves will likely sit there and rot with nowhere to go. You don't want to compromise your living plants by introducing rot from a few dead leaves, so remove any dead matter as soon as you can.

Keep the glass clean

Terrarium plants require light to grow just like any other plants, and a dirty terrarium can restrict a lot of that light. 

Keep your terrarium glass clean by gently wiping the interior with a lint-free cloth and purified water. You can also prevent residue buildup by watering your terrariums with mineral free water to prevent calcium buildup in the soil and on the glass!

Use these tips to help you understand how your terrarium works, what you can do to keep it healthy and, of course, how to help it thrive!

Good luck!

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Featured photo courtesy Unsplash/Maud Bocquillod