Use a log that is at least six inches tall and at least six inches in circumference. Choose a log that has a rotten center if possible; this will make it easier to hollow out. Select a larger log if you want to use multiple plants or one bushy plant.
Put on a pair of leather gloves. Cut one end of the log with a hand saw so the log will stand on its end without wobbling. Use a vise grip to hold the log while cutting.
Hollow out the top half of the log by drilling holes in a circular pattern with a drill and a hole saw bit. Hollow out the log until you are one to two inches away from the bottom of the log. Use a hammer and chisel to remove the wood between the holes.
Flip the log over so the bottom is facing up. Drill a drainage hole in the center of the bottom of the log with a drill and drill bit. Make multiple holes around the bottom of the log for larger planters.
Flip the log so the hollow top is facing up. Pour a thin layer of small pebbles in the bottom of the log. Cover the pebbles with a layer of soil.
Place your plant into the log planter. Spread out the root system carefully. Add more soil to the bottom of the log so the top of the roots is just below the rim of the top of the log. Pour more soil around the plant's root system and water thoroughly.