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A completed flask terrarium against a lilac background with decorative moss scattered around.
Make a Flask Terrarium
Make a Flask Terrarium
Make a Flask Terrarium

Make a Flask Terrarium

London Terrariums
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  • Botany
  • Type: Kit + Online Course

Learn how to make a terrarium using this unique shape and add a bit of chemistry to your interiors.

The Flask Terrarium is a unique shape that London Terrariums will teach you to master. The familiar shape and charming green contents evoke a chemistry lab meets rainforest. With a small, elongated spout, the results are well worth the steady hand and careful execution needed to complete this project. Both its iconic silhouette and ‘ship in a bottle’ novelty make the Flask Terrarium a beautiful living ornament in any home.

In step-by-step instructions and photographs, Emma Sibley from London Terrariums will take you through the steps to create your terrarium, with plants, pebbles and moss. You'll also get to grips with the terrariums history and their recent resurgence, understand how they create their own water-cycle and self-contained ecosystem, and you'll learn exactly how to care for them. You’ll even learn how to make your own tools from household items in order to best create your demijohn terrarium.

By the end of the course, you will have your own miniature garden to watch grow and develop over time in your home.

With UNLIMITED ACCESS 24/7, you’ll be able to drop in and out of the course at your own pace, and refer back to it anytime. By the end of this course, you will be able to:

  • Expertly clean and prepare your jar
  • Combine pebble, moss and plants in the optimum quantities
  • Select and use specialist terrarium-making equipment and materials
  • Understand how terrariums create their own water-cycle and self contained ecosystem
  • Care for your finished terrarium
  • Make professional standard terrariums from household jars

Expert Emma will share with you her foolproof step-by-step method, so you can make your own professional terrariums at home.

She will also share with you top care tips and common mistakes to avoid, so you can keep your terrarium healthy and happy. With this course + kit, you'll learn a life-long skill and enjoy making your own custom terrarium from scratch, for the same price as buying a ready-made one.

You can try out a free taster course with Emma and learn how to take care of your terrarium.

Making Made Easy with Yodomo

About this online terrarium course

How do I learn with Yodomo online courses?

You will receive an email up to 15 minutes after purchase with details on how to access your course, and if you are a first-time user, how to set up your account. Your courses will then be available to access 24/7 on any device, simply by going to My Courses at and logging into your account.

How is the course taught?

Yodomo courses are taught by select instructors, who are experts in their field. Each course breaks down complex craft skills into easy-to-follow step by step guides, which combine video, photography and downloadable PDFs.

You can learn anytime, anywhere, on any device with Yodomo, simply by going to My Courses and logging into your account.

Is this course suitable for beginners?

This terrarium is easy to complete and suitable for every level. Creating your own simple plant hanger is made easy with step-by-step guidance and tips by expert maker Emma Sibley of London Terrariums. From understanding the science behind these self-sustaining ecosystems to the best techniques for building your terrarium, Emma provides top tips and easy-to-follow directions that will allow your terrarium to thrive.

Course curriculum


  • What you'll make
  • Meet Emma Sibley
  • Terrariums: A Short History

What you’ll need
The Science of Terrariums
Selecting Your Plants

Step 1: How to make your homemade tools

    • How to make your tools
    • The sponge brush
    • The Patter
    • The funnel

Step 2: Clean the Vessel

Step 3: Funnel stones into the Vessel

Step 4: The Activated Charcoal

Step 5: Add Compost

Step 6: Preparing the Plants

Step 7: Adding the Plants

Step 8: Add Moss (Optional)

Your Finished Terrarium and Course Tips

    • Your finished terrarium
    • Emma’s top tips

What do I need for this course?

You can source the required materials from most garden centres. Contact us for advice if you’re unsure of where to find these items or post in our support Facebook Group.


  • Flask vessel & cork (we suggest about 2 Litres)  
  • Cork base for your flask 
  • Selection of moisture loving houseplants (e.g. Fittonia. Ivy, Baby’s tears, button fern, FIcus Pumilla, Muehlenbeckia) 
  • Compost Tub and Basket compost (about 0.7 Litres) 
  • Carpet moss 
  • Washed small stones (Garden gravel or aquarium gravel works very well in Boiling Flask terrariums) 
  • 1 heaped teaspoon activated charcoal (found in health food stores) 
  • Funnel (can be made from half a broken plant pot) 
  • Teaspoon 
  • Water spray bottle 
  • Water 
  • Radiator brush and sponge brushes (sponge end steam bent over the kettle) 
  • Cork at the end of a stick (for patting down the soil) 
  • Long tweezers, with bent end 
  • Kitchen roll 

Course preview

Make a flask terrarium course preview

Yodomo online courses - supporting you at every step

Join the Yodomo Makes Facebook group, where you can post any queries or questions you have, and an instructor, Yodomo team member or member of our community will be there to support you.

Meet your instructor, Emma Sibley from London Terrariums


    Emma says, "Fundamentally, it's not only about creating aesthetically beautifully objects. For us it is the deeper fascination with how plants behave and the exciting part terrariums play in the history of horticulture."


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    Emma Sibley of London Terrariums standing in her shop front in New Cross.

    London Terrariums

    London Terrariums is run by Emma Sibley. From making terrariums for friends and family to the shop opening in 2017, London Terrariums is where you can buy ready-made terrariums, kits or attend a workshop. Emma is a member of the British Cactus and Succulent Society.