DIY: Glass Jar Terrarium

London, U.K.-based author and green thumb Emma Hardy shares a DIY project from her latest book, The Winter Garden (Cico Books, $20).

Terrariums are a lovely way to create small gardens inside the house, and are often used to grow succulents and ferns. Displaying flowering plants in an open-topped glass jar creates a pretty indoor garden that will bring color and beauty into your home.

You will need:

• Large glass jar with a wide neck
• Gravel
• Ground charcoal (pet stores should stock this)
• Potting compost
• Scoop
• Helleborus niger (choose an alpine variety with a small root ball), viola x wittrockiana (pansy), humata tyermanii (bunny fern). *Or, ask your local plant store what’s in season in your region.
• Moss
• Soft paintbrush

Step 1: Clean and dry the jar thoroughly before you start. Carefully place a layer of gravel in the bottom of the jar (adding it in handfuls rather than pouring it in, so that it does not shatter the glass). The gravel should be about 3⁄4 inches (2 cm) thick and evenly spread over the bottom of the jar.

Step 2: Sprinkle charcoal powder over the gravel, completely covering it. This will help to absorb odors from the potting compost, ensuring that the terrarium does not smell.

Step 3: Check that the potting compost is damp before using—water it if necessary, letting it drain slightly before using it. Add the potting compost to the jar, making
 a layer about 2 inches (5 cm) thick. Add it using a small scoop or your hand rather than pouring it in, so that
 it does not make too much mess inside the jar.

Step 4: Take the hellebore out of its pot and carefully remove any excess soil from around the roots. Make a shallow dip in the potting compost inside the jar and place the hellebore in it, spreading the roots out a little and anchoring it in place with a little more potting compost if necessary, so that it sits firmly upright.

Step 5: Take the pansy from its pot and plant in the jar in the same way, placing it toward the back of the jar, next to the hellebore.

Step 6: Add the fern, again removing excess soil from the roots, and plant toward the front of the jar, adding more potting compost if necessary. Firm around all three plants so that they sit firmly in the compost.

Step 7: Tear the sheet of moss into pieces and place them on the surface of the potting compost, around the plants. Make sure that all the potting compost is covered, adding smaller pieces of moss if necessary.

Step 8: Using the soft paintbrush, clean up the inside of the jar and brush any bits of potting compost from the leaves and flowers to tidy them up.

Aftercare
Make sure that the potting compost remains moist but not too wet (stick your finger into the compost to check), watering sparely when necessary. Keep the terrarium indoors in a light spot and deadhead the pansy regularly. With the right conditions, the plants should keep flowering for several weeks or even months, but the foliage will look lovely too.