Hi folks - some friends showed an interest in my new hobby of creating terrariums, so thought I'd post some instructions for anyone who'd like to try. They're expensive to buy, but surprisingly cheap to make yourself! Have fun!
Making Your First Terrarium
What You’ll Need:
Some basic tools – here is a pic of what I use. They’re only really needed when you’re using a container with a narrow neck. I found the long-handled tongs in a pet shop, sold for use with aquariums.
Glass container, with or without a top
Clean gravel or small stones. For a prettier effect I tend to go for coloured gravel or even glass pebbles, available almost anywhere. But if you’re near a beach or river, smooth washed pebbles are easy to find.
Activated charcoal (Sold in Pet Stores for use in reptile houses, or online)
Sterile potting mix
Sheet moss, often called Sphagnum moss, available quite cheaply from Garden Centres or Pet Stores, or online.
Other types of good-looking moss for filling between plants. This can be quite difficult to find in shops. Can be bought online, but quite expensive. I suggest gathering your own. A walk in the woods or by a river can be productive, or if you have a garden try checking the more shady areas – you could be surprised!
Decorative elements (optional). I like to theme my creations by adding small figures, etc. Check the pics at the end.
Choose a Container
Choosing your container and plants is half the fun of making a terrarium. There are many specialized terrarium containers that you can buy, even some that look like miniature Victorian greenhouses or conservatories that sell for a small fortune.
But you can use almost any transparent container with or without a lid to create a terrarium. I find mine mainly in Charity Shops or at Car Boot sales!
A wide opening allows you to fit your hand into the container to add drainage material, soil, plants, and decorative elements (shells, figurines, or ornaments), but a narrow opening is probably better for a sealed terrarium, and the tools shown earlier will help to work with this type.
Choose the Plants
Most garden centres stock miniature plants for terrariums, and they are also available cheaply online. Choose plants with various foliage forms and heights. Most small plants will do well in a terrarium, but here are some examples of commonly used ones:
African Violet, Pothos, Small Ferns, Fittonia (comes in many colours!), Prayer Plants, Creeping Fig etc. Succulents also do well in a terrarium.
Add Drainage Layers
A terrarium container does not have drainage holes, so you’ll need to create a drainage layer to keep water away from plant roots. Start with a 1 -2 inch layer of gravel or crushed stone at the bottom of the terrarium. A tall, narrow terrarium will require a deeper layer of drainage stones than a broad, shallow container.
Add Moss and Potting Mix
Then add a layer of sphagnum moss over the stones to keep the next layer, the potting soil, from being washed down into the drainage layer.
Next, add a 1/4-inch to a 1/2-inch layer of activated charcoal on top of the stones to help with drainage and control any odours.
With a large spoon or small trowel, add slightly damp potting soil on top of the moss. Do not use a potting soil mix with fertilizer already added as terrarium plants don't need the extra fertilizer, what they need comes from natural decay.
Add as much potting mix as you can—at least a couple of inches. Make sure to keep the soil level low enough so that the plants will fit inside the container with room to grow.
Prepare the Plants
Before planting, decide on the design of your terrarium. Choose the spots where you'll place tall and short plants and where you'll create mounds and dips in the soil to create interesting contours.
Remove the plants from their nursery pots. If a plant is rootbound tease the roots apart or use a pair of small garden snips to trim off some of the longer roots. Removing some roots will slow a plant’s growth, which is essential when growing plants in the confines of a terrarium. Also, trim off any yellowed or damaged leaves.
Shake off any excess soil left on the plants. Use a long spoon or your fingers to dig a planting hole for each plant. Place each plant in its hole and gently pat the soil down to eliminate air pockets and secure each plant firmly in the potting medium. If the terrarium has a narrow opening, use chopsticks or long tweezers to place the plants into the terrarium. Put a cork on the end of a skewer or chopstick to tamp down the soil.
At this stage I like to fill the spaces between the plants with the more good-looking mosses. When you start to collect some, you’ll be amazed at the varieties available!
Then just get creative and decorate the inside of the terrarium with small figurines, shells, decorative stones, or anything else that comes to you!
Water the Terrarium
Use a spray bottle or small watering can to water the plants so they are just damp, but not soaking wet.
Use the spray bottle to clean off any dirt clinging to the glass sides of your container, which you can then wipe clean with newspaper or a paper towel. Never use glass cleaner on the inside of a planted terrarium because it can harm the plants.
And that's about it! Have a go, and if you do, please post your work here. Here are some pics of my efforts so far. Sorry about the quality - not a great photographer.