First assemble all your supplies! 1.Glass jar or container with a lid and thin walls or sides. 2. Pebbles or grit: This will serve as your water drainage at the bottom of the terrarium. I typically put in about a 1/2 to 1 full inch of pebbles. 3. Activated charcoal to clean and purifie the water you add to the terrarium. I put a thin layer over the gravel: about 1/4 cup. 4. Potting soil: You need to use seed starting soil, which is semi-sterile. Do not use soil from your garden or backyard. I put in soil about 1 to 3 inches deep. 5.Moss: You can use pretty much any type of moss you can find, but do not use mosses that self-compost: the easy way to spot these is to look on the bottom of the moss for any dead leaves or other dead things that are composting instead of roots. Steps to making your terrarium 1.Put in gravel (1/2 to 1 full inch). canning jar terrarium 2.Add charcoal (about 1/4 cup) 3.Drop in dirt (1 to 3 inches deep), and make a hill-like shape out of it inside your terrarium. 4.Add the moss and ferns (other non-roting objects like clay or special rocks.) 5.Water the roots of the plants and add lid. 6. Find a good place for your terrarium. Terrarium Placement and Care: Place your terrarium in indirect or filtered sunlight. If it’s in a full sunlight, it will grow too fast and/or bake. Water terrariums about once every three months with an eyedropper, that’s all the water it needs! Don’t put much water in—just a little bit. You will know if it needs water if the terrarium looks or smells dry.