Things You'll Need
Instructions
Prepare your box to hold the soil and water. Any size box will work, as long as you have enough soil and vegetation to fill it. If you only have a cardboard box, line it with some tin foil to ensure the water won't eventually eat away the box. A plastic box will work best.
Line the bottom of the box with rocks about three deep. Then take biome-appropriate soil or sand and fill the box about halfway up the sides. If you're doing an evergreen forest biome, take some soil you think you would find there. A desert biome might require some sand.
Plant biome-appropriate vegetation in the soil. Again, think about the biome you are trying to create -- a palm tree might not grow in a tundra biome. Plant the vegetation as you would in a garden, covering the roots and keeping the plant firm in place.
Water your plants from time to time and watch the biome grow. If you overwater the biome, consider poking holes in the bottom with scissors to let your biome drain and stay healthy.