What you need:
A (glass) pot with a hole in the bottom
A smaller pot, e.g. a jam jar
A 100% cotton T-shirt
Scissors, wire cutter/pliers
Roll of wire
Thick wire for the hanging system
How to make it
Use wire to make a sturdy ring around the larger pot, and twist three loops into it that will take the fabric strip in due course. Create a ring with loops for the smaller pot as well; the wire must be tight enough that the pots cannot slip through the ring.
Cut four strips out of the T-shirt approximately 1.5 - 2 cm wide and at least 40 cm long (you can always trim them later) and tie three of them to the loops. Tie the ends of the fabric strips together. Cut out another three strips to attach the small pot to the larger pot, also 1.5 - 2 cm wide and at least 25 cm long.
Use the stick to carefully push the fourth fabric strip deep into the plant's soil, place the plant in the pot and pull the fabric strip through the hole at the bottom.
Hang up the large pot and hang the small pot below it by attaching its fabric strips to the ring on the large pot.
The small pot should hang about 10 cm below the large pot; you can place a good length of the fabric strip from the large pot in the small pot. Make sure there is always enough water in the small pot, and the plant will then take up the moisture via the fabric strip. Talk about self-sufficient!