Tovah Martin: photo: Susan Johann

With most outdoor garden chores winding down, I turn my attention indoors – to  my houseplants. But indoor gardening can be way more than  plants growing in pots.  With a little imagination, you can turn a few plants, some pebbles and glass into a captivating vignette – in other words, a terrarium.

A few months ago, I read a new book by horticulturalist and writer, Tovah Martin, entitled “The New Terrarium.” I have always found terrariums fascinating. I made one as a child one summer out of moss and ferns, and it was so lush and green and mysterious inside. I kept it by my bed and looked at it – or into it – every day.

After inviting Tovah to lead a terrarium workshop for our Master Gardeners (she said yes!) I asked her a few questions about the book, and her obvious interest in this facet of indoor gardening.  Here’s part of our conversation:

Why are terrariums so appealing? Is it because they are like little “parallel universes?”

“Parallel universes is certainly an apt description.  I like to call them ‘small worlds.’  There’s an element of fantasy to a terrarium – like someone shrank the ecosystem.  But there’s also the creativity factor – a terrarium is a design challenge in miniature.  And everyone can succeed with a terrarium – it can even survive in your office cubicle.  Plus, it’s the ideal venue for soaking up stress.”

Are they enjoying a resurgence in popularity?

“Absolutely – terrariums have gone through several spikes in popularity – first in the mid-1800s, then in the 1970s, and now.  The current trend features a sleeker, simpler terrarium compared to its more fussy predecessors.”

What made you want to write about them?

“I’ve been growing terrariums for many, many years.  Actually, Clarkson Potter came to me with the project (I was recommended by another of their authors – Ken Druse), but I jumped at the opportunity.  The book definitely fills a gap.  And I was lucky to team up with Kindra Clineff, who created truly brilliant photos.”

Can you name a few plants that are best suited to terrarium culture?

“Ferns and tropical mosses (selaginellas) are some of the easiest terrarium plants.  Other very appropriate plants are rhizomatous begonias, orchids, peperomias, pileas, and members of the African violet family.  Basically, you want a plant that likes high humidity and indirect light.  And the plant should remain miniature.”

Tovah Martin's new terrarium book

Are there some plants that are not suited?

“Yes, plants that prefer sunny and dry growing conditions are not going to thrive – succulents and alpine plants quickly perish in a terrarium.  Most herbs also do not succeed – mints are an exception, they like shady, moist conditions, so they can be grown in a terrarium.”

What are the most important guidelines for a successful terrarium?

“Location, location, location.  Grow a terrarium in indirect light  –  direct light can quickly bake (read that fry) the plants in a terrarium.  Correct planting is also critical – firming the plants into the soil is a crucial step.  Basically, you follow all the same rules that govern planting out in the garden.”

Can you describe some common mistakes and pitfalls?

“Many people think that misting is necessary.  Actually, misting is a really bad idea in a terrarium because the environment is already moist.  Keeping the plants inside a terrarium clean is also critical.  Grooming, removing past-prime flowers, and cleaning the glass are all necessary for terrarium hygiene.”

Is your house full of them?

“Everywhere.  I counted 22 at one point, all sorts of shapes and sizes, but I finally ran out of room and sold some at lectures.  Now they’re beginning to stack up again.  It’s hard for me to part with a terrarium once I’ve planted it.  I guess that I don’t want to lose the small world I’ve created.”

Do they make good office accessories?

“They’re perfect for the job.  Not only do they soak up stress, but they require almost no care.  And they’re contained, so they aren’t messy.  Plus, they love fluorescent lights.”

What sort of set-up would you recommend to a beginner?

“I think that a simple jar with a mouth large enough to fit your hand into and a lid is the ideal vessel.  Apothecary jars are perfect for the purpose.”