5 Common Terrarium Mistakes (and How to Avoid Them)

Terrariums are an enchanting way to bring a slice of nature indoors, blending creativity with the joy of plant care. While they’re famously low-maintenance, a few common mistakes can lead to problems if you’re not careful. Don’t worry, though—with a little guidance, your miniature world will thrive. Here’s how to avoid the most frequent terrarium mishaps and set yourself up for success.

1. Overwatering: Less is Always More

One of the easiest ways to upset your terrarium’s delicate balance is by overwatering. Terrariums don’t have drainage holes, so excess water can quickly lead to soggy soil, root rot, and an unhappy ecosystem.

How to avoid it:

• Use a mister rather than pouring water directly onto the soil.
• Only water lightly when the soil appears dry—remember, closed terrariums recycle moisture, so they rarely need watering.
• If you’re using one of our Happy Houseplants Terrarium Kits, the included mister ensures precise control, helping you avoid this common pitfall.

2. Poor Plant Selection: Match Their Needs

Not all plants are suitable for terrariums. Mixing plants with different light, humidity, and water needs often spells trouble. For example, pairing a desert succulent with a humidity-loving fern is a recipe for disaster.

How to avoid it:

• Stick to plants that thrive in similar conditions. Popular choices include mosses, fittonias, and small ferns.
• If you’re new to terrariums, choose a pre-curated selection like the plants included in our terrarium kits, which are specifically chosen for their compatibility.

3. Lack of Ventilation: Let It Breathe

While closed terrariums are fantastic for tropical plants that love humidity, some plants struggle without proper airflow. Stagnant air can lead to mould growth and unhealthy plants.

How to avoid it:

• If you notice condensation building up inside your terrarium, open the lid briefly to allow fresh air to circulate.
• For plants that prefer airflow, consider an open terrarium design instead.
• Remember, every terrarium is unique, so tailor ventilation to the needs of your chosen plants.

4. Too Much Sunlight: Don’t Fry Your Plants

It’s tempting to display your terrarium in a sunny spot to show it off, but direct sunlight can quickly turn it into a sauna. The glass container traps heat, which can scorch plants and dry out the substrate.

How to avoid it:

• Place your terrarium in bright, indirect light. A spot near a window with filtered light works best.
• Avoid direct sunlight at all costs, especially during summer months.

5. Skipping the Charcoal Layer: Don’t Forget the Basics

The activated charcoal layer is often overlooked, but it’s a crucial part of any terrarium’s ecosystem. This layer keeps the environment fresh by filtering impurities and preventing unpleasant odours.

How to avoid it:

• Always add a thin layer of activated charcoal between the drainage stones and the substrate.
• Our Happy Houseplants Terrarium Kits include pre-measured charcoal, so you’ll never forget this important step.

Setting Yourself Up for Success

At Happy Houseplants, we believe creating a terrarium should be fun and stress-free. That’s why our terrarium kits are thoughtfully designed to eliminate guesswork. From curated plants to perfectly measured materials, we provide everything you need to create a thriving tiny world.

Looking for More Tips?

Dive deeper into the art of terrariums with our interview with Worcester Terrariums and explore the creative possibilities of these miniature ecosystems. Share your creations with us on Instagram using #HappyHouseplantsTerrariums—we’d love to see your masterpieces!

For more expert advice on houseplant care and styling ideas, check out the Happy Houseplants blog. With a little knowledge and the right tools, your terrarium will become a captivating addition to your home.