School holiday activity - create a terrarium

Looking for something to keep the kids occupied these school holidays? Rather than plonking them in front of the television, why not get their hands a little dirty with this fun terrarium project, supplied by kidsgardening.org.

A terrarium is a miniature garden grown inside a covered glass or plastic container. It is a low maintenance way to incorporate plants into your classroom or home and an excellent tool for teaching children about the water cycle as it demonstrates evaporation, condensation and precipitation. In the presence of light and heat, water evaporates from the plants through transpiration and from the soil. Since it is an enclosed environment, when the water vapor hits the side of the container, it condenses. Once enough water accumulates or the temperature decreases, the condensation will then precipitate down the sides of the container back into the soil.

You will need:

• an enclosed container
• pea gravel or small rock
• potting soil
• small indoor or tropical plants
• charcoal (optional)

Instructions:

1. Find an appropriate container. Glass jars, fish bowls and tanks, clear plastic bottles and food containers can all make fine terrariums. Just make sure there is enough room to reach your hand into your container for planting and maintenance.
2. Clean the container using soapy water and rinse well. Dry completely.
3. Cover the bottom of the container with ½ inch (for small containers) to 1-1/2 inch (for large containers) of pea gravel for drainage. This mimics the bedrock found under our soils and allows access water to drain from the soil. You can also add a few granules of filtering charcoal (not the type used for barbecuing) to the top of the gravel to help remove odors. The charcoal is optional and is not needed if your terrarium maintains proper moisture levels.
4. Next fill the container to approximately one-third to one-half full with moist potting mix. The amount of soil you put in will depend on the size of the container (you need to have enough room for plant roots). You should use a sterilized potting soil mix to avoid problems with molds and fungi (small bags of potting soil are available at most garden centers). The moisture level of the soil when you put it into your terrarium is very important. Pour the soil into a bowl or tub and mix with water until the soil is moist enough to cling together in a ball when pressed into the hand. If water drips from the soil when pressed into a ball, then it is too wet and you should add more dry potting soil to your mixture. Once you find the perfect balance, place the soil in your container. Try to avoid getting soil particles stuck on the sides of the container above the soil level.
5. Next add your plants. You need to look for plants that are small, slow-growing, and perform well in humid environments. How you arrange the plants will depend on the size and location of the terrarium. If you will be viewing the terrarium from one side, then place the tallest plants in the back and shortest plants in the front. If your terrarium will be viewed from all sides or you plan to rotate it, plant the tallest plants in the middle and the shorter plants along the outside.

There is a wide range of plants to choose from. Most garden centers have an area reserved for indoor plants and you can usually find a variety of plants in 2 to 4 inch pots.