Terrariums Pt. 2-Care and Planting

By Melanie Mathieson
Gardening Guru

Now that you have purchased your supplies using the tips from Part 1, you are ready to get started with the planting process.
Wash the container well with soapy water and rinse it completely to remove any soapy residue. It the container was previously used for another use, wash it thoroughly as suggested above, wash with a ¼ household bleach to ¾ warm water solution, then rinse thoroughly. The cleaning and rinsing step is imperative, as a dirty terrarium will grow bacteria and/or mould over time, which will eventually cause a decline of the environment and possibly kill the plants.
•Sheet Moss – This is the first layer to install, if you are using (remember I recommended this for larger containers only). Wet the moss first so it is slightly wet to the touch but not waterlogged and then layer it into the bottom of your container. Sheet moss can be cut with scissors or torn to fit.
•Pebbles or Gravel – Make sure to clean the pebbles and/or gravel before placing in as the second layer. Clean this layer using the same instructions as for the container. Placing the pebbles in a colander helps to make the task a more manageable. Arrange the pebbles on top of the sheet moss until about 2.5 centimetres thick. Make sure they have not squished the sheet moss too flat. If this happens take out the pebbles and remove the sheet moss, then place the pebbles in as the first layer.
•Activated Charcoal - As this is the crucial component for keeping your terrarium healthy (it keeps the water from going stagnant), sprinkle a generous amount over the pebble layer until all pebbles are covered and the layer is about 1–1.5 centimetres thick.
•Sheet Moss – Reinstall your sheet moss over the charcoal if the pebble layer was too heavy.
•Soil - Premix your soil, for a terrarium containing green plants, by adding five parts of potting soil mix directly from the bag into a mixing container and adding one part each of vermiculite and perlite. If you only have one or the other, add two parts of the vermiculite or perlite. For a cacti terrarium mix ¾ potting sand with ¼ potting soil. Depending on the size of the terrarium and the length of the plants’ roots, you should be adding at least 5 to 8 centimetres of soil. Measure the depth of the roots of the plants you plan to use to make sure you have enough soil to cover the roots completely. Gently pack the soil down to remove air pockets and level the surface. Dig little holes into the soil where you’ll put the plants.
•Plant the Plants – Remove the plants from their containers. Break away all excess soil but making sure not to disturb or tear away the tender roots. Plant in the desired location within the terrarium making sure the plant is snuggly and completely surrounded by the soil in the terrarium. Continue planting until all plants are inserted.
•Water – For the first watering, water slowly allowing the soil to fully absorb the water. You may have to water a few different times to ensure the soil is very moist but make sure it is not waterlogged. It is best to water gradually over a few days, than all at once, risking the chance of overwatering and flooding your terrarium. If your terrarium is open, water the plants occasionally when the soil is dry to the touch and you cannot see any water present in the pebble layer. Open terrariums with succulents need to be watered once a month and with cacti usually every 1-2 months.
Airtight terrariums only need to be watered after the initial watering when the condensation on the inside of the glass is completely gone. Make sure that with a cactus terrarium there is no condensation buildup on the glass. If this occurs you have overwatered and the terrarium needs to be exposed to the air until the soil and the glass dry out.
•Decorating – This is the last and most fun step. You can add a layer of sheet moss on top of the soil to keep everything green and tidy. You can also top the soil with another layer of pebbles, glass stones or gravel, or leave the soil exposed. Terrariums can be decorated with miniature figurines, pieces of driftwood, shells, rocks or other decor items. It is your terrarium so decorate however you wish, just ensure the elements you insert, are cleaned beforehand.
Terrariums are great because they are low maintenance, but in order to remain so they must be placed in an ideal location. All plants need light and plants in terrariums are no exception. However, since glass is magnifying, choose a location where your plant will receive plenty of indirect light but is away from direct sun exposure. Cacti, succulents and some tropicals need more light, so a location near a window is good. Low light tolerant tropicals and other plants can be placed in a more out of the way area like in an office or a livingroom and used as a decorative element in a room. Optionally, you can choose the artificial lighting within a room as your light source, just ensure that it is a enough for the types of plants you have. If the light is inadequate you will see yellowing plants very quickly.
Terrariums should be kept inside, in a heated room in an area that avoids extreme temperatures or sudden changes in temperature. If your terrarium is airtight, it is a good idea to occasionally air it out. If your plants are wilting or there is excessive condensation on the sides of the terrarium allowing the container air out will help- to dry and freshen up the terrarium’s environment.
If you see weeds, mouldy soil or plants, or sick plants, immediately remove the affected area(s). You should also be careful to remove any wilting parts of plants, including old flowers. If the entire soil area becomes mouldy you may have to air the terrarium out and then replace the top layer of soil. Be careful not to overwater once the soil is replaced.
Using these tips you should have good success and be able to enjoy your own terrarium for many years. Always be careful not to let the terrarium get too dry or water it too much. Even temperature, light and water are your keys to success.