Build a mini rainforest

When I was a kid (it’s a while ago now!) we built a mini rainforest in my science class which illustrated how the rainforest water cycle worked. This got me to thinking about doing the project again!

The basic idea is, grab a container (an old jar or maybe a small fish tank) and fill the bottom with an inch of sand/gravel. Over the top of that put an inch of soil and compost.

Grab a few plants African Violets seem a popular choice, but ferns are great as well. If you really want to be impressive, grab an orchid and stick that in there as well.

Carefully plant your ‘rainforest’ vegetation and give it a good old watering.

Now put something over the top of the fish tank or jar, cling film if its a small jar or a piece of cover glass if its a fish tank and put your new mini rainforest somewhere light. Make sure it isn’t in to much direct sunlight or the poor plants will cook in there!

Don’t forget to put a nice big rock in there for decoration

Now sit back and watch as your mini rainforest starts the cycle of taking up water from the soil through ‘transpiration’, using the nutrients they need along the way and then releasing the water back into the system through ‘evapotranspiration’ as the water evaporates into the air. The water droplets on the surface of the tank or jar are caused by the water in the air ‘condensing’ on the cold glass and then drop back down to the soil for the roots to take them back through the plant again.

This cycle is important for plant life, but it’s also important for sustaining the land. The process works like a huge filter (like the one that you might have had in the fish tank you are using now).

If you see a bit of mold appearing in the jar then lift the lid off and let some air in to circulate. You shouldn’t have to water your rainforest for 4 weeks or more!

If you have done this project before at school or at home, then we would love to hear from you and see pictures of your own mini rainforest. Just use the comments form below to tell us about it.

If you need some instant inspiration, check out these pictures on flickr! Thanks to Katie Mancine for the permission to use the terrarium image in this post.