When you set them up correctly, they are the easiest things to take care of because they take care of themselves. But before we get into the nitty gritty of terrariums, let’s go over some basics. There are two kinds of terrariums, open and closed. Open terrariums are ones without lids, or that have holes. These allow new air into the container, and often need more care because of the evaporation effect. Closed terrariums are the ones you might have studied in school. They are a closed system, and therefore have the capabilities of watering themselves, and give that whole ‘ecosystem-in-a-jar’ look. Either way, terrariums need the right start, otherwise they’re just a pain to deal with. Open terrariums are best for succulents or ‘dry’ plants, while closed terrariums are great for water-loving ones. Now, substrate is key when you build up your terrarium! It’s not just dirt, but a lasagna of charcoal, bark, soil, and gravel. Charcoal is something that I feel not enough people utilize in terrariums, and it might just be the most important. In a terrarium (especially a closed one), you have a cycle of water going down into the soil, settling down in the bottom, evaporating up to the lid, and then condensing and dripping back down onto the soil. But if you don’t have charcoal, the water doesn’t stay fresh. Charcoal is like your filter, so put it at the bottom of the terrarium, followed by a thin layer of bark, and a thicker layer of soil. After your lasagna is ready, put your plants in place, and after arranging everything put a top layer of wet sheet moss or even live moss. The wet moss is your supply of water for the terrarium, so only add more water if you notice there isn’t condensation. Be careful not to overwater! Fill in bare spots with gravel to keep everything in place. Pinch back your plants when necessary, and watch the cycle of nature do its thing. It’s that easy. If you’ve never owned a terrarium before, or want to buy all the products necessary but don’t want huge bags of charcoal and orchid bark, then try our Terrarium Kits. They have everything you need, and come with really great detailed instructions.