A paludarium is a cross between an aquarium and a terrarium, encasing a miniaturized world of unusual landscapes and plants in a tropical environment. Children, such as Martha's friends Kemper and Signe, often find that paludariums offer the ideal terrain to place such toys as plastic dinosaurs and alligators.

Tools and Materials
Glass tank
Glass divider
Silicone sealer
Smooth pebbles
Gravel
Ground carbon
Soil
Small tropical plants

Making a Paludarium How-To
1. Insert the glass divider with a thick line of silicone sealer (available at pet stores) so that it divides the tank in two; test it to be sure it's leakproof. You can camouflage the divider by gluing small pebbles to the front of the tank.

2. Set up the terrarium portion of the tank by covering the bottom with a 3/4-inch layer of clean gravel, followed by a 1/4-inch layer of ground carbon, and a layer of soil. The layer of soil serves as the base of your landscape and can be used to transform the terrain, like creating a hill. Once it's arranged, lightly tamp the soil, and dig small pits just large enough for the plants. Place plants into the holes, being careful not to damage the roots and planting them no deeper than they were in their pots. Once they're in place, be sure to prune away dead or yellowing leaves, trim plants that are growing too large, and replace any ones that aren't thriving. Mist the plants daily.

3. To assemble the aquarium portion, place a well-cleaned layer of gravel or rocks on the bottom of the tank, and add enough water to come near, but not over, the top of the glass divider. Add any plastic animals you'd like to include.

4. To make sure your paludarium thrives, don't place it in direct sunlight, and keep it away from direct heat sources. Be sure the tank has a lid made from Lucite, Plexiglas, or other acrylic plastic that will fit snugly. Remember that terrariums, and by extension the terrarium portion of your tank, most often fail due to overwatering. If, however, you water your plants and they still seem dry, moisture is evaporating. Check the lid to make sure it has a tight fit. If the walls get so foggy it's difficult to see inside, leave the lid ajar to let the moisture evaporate.