How to make an open terrarium

Terrariums are one of my favourite plant decorations to do. They are so decorative and actually very easy to care for as long as you find the right plants. There are different types of terrariums. Closed terrariums create their own mini eco-system by reusing water and oxygen. Because of its very humid environment, they are perfect for tropical plants. Open terrariums allow more air circulation for plants like cacti, succulents and air plants. In this post I will guide you how to make an open terrarium. Do you want to learn how to make a closed terrarium, you’ll find my guide here.

What plants can I use?
The first step is to find the right plants. Open terrariums are perfect for cacti, succulents and air plants.. However, I will not recommend you to mix cacti and succulents in the same glass container. Succulents need more water than cacti, so it will never be a perfect match. For my open terrarium I have chosen three different types of cacti that I really like.

What glass container can I use?
You can use any glass container you like. Only requirement is that they are clean, waterproof and light can shine through. A visit to your local second hand shop will give you lots of options for finding the perfect container. But keep in mind that containers with smaller openings are harder to plant than containers with large openings. Also large openings allows more air circulation, which is very important for your cactus or succulent to survive.

Step 1: Pebbles

Because terrariums don’t have drainage, you will need to make a layer of pebbles of 3-7 cm in the bottom. Drainage layers help ensure excess water doesn’t stay in the soil and cause root rot. Pebbles can be bought in most plant shops or in aquarium stores.

Step 2: Activated charcoal

Next layer is 1 cm of activated charcoal, which filters the air and water and keep the terrarium clean. You can buy activated charcoal in every aquarium store.

Step 3: Potting soil

For potting soil I use cactus potting soil. It has superior drainage and will dry out quickly after watering, which forms a better basis for cactus roots than regular soil and keeps roots and stems from sitting in moisture. You can buy cactus potting soil in most plant shops and garden centers.

Step 4: Plants

At last you plant your terrarium. If you have chosen cacti for your open terrarium, you can either use tweezers, gloves or an old newspaper around the cactus, so you won’t hurt your self planting it the terrarium.

Step 5: Topping

For completing the look of my terrarium I have topped the soil with a layer of white pebbles. You can also use other decorative items as small figures, driftwood, seashells etc. It is up to you how you want to decorate your terrarium.

How to take care of my terrarium?

Watering
Succulents or cacti should be watered very sparingly, just as you would with these types of plants in any container, and keep an eye on any accumulated water. Remember, terrariums have no drainage holes, so when they feature arid plants, try only adding a dropperful of water at a time. Air plants will need to be taken out of the open terrarium, soaked in water for 20 minutes each week, then allowed to thoroughly dry out before they’re returned to the terrarium

Fertilizer
You don’t need to fertilize your terrarium un less your plants shows signs of nutrient deficiency, and you can see it is not because of need for water. Use fertilizer specified for cacti.

Light
Air plants thrive best in indirect light, while cacti grows best in bright sunny spots. Succulents thrive in bright indirect light. Always remember to choose plants with same need for light for your terrarium.