Outdoor containers can be temporarily turned into self-watering containers while you are on vacation. This method will keep plants well-watered for approximately two weeks. Recycling plastic bottles is the most economical way to turn your outdoor containers into self-watering containers. Collect and save plastic bottles, preferably two liter soda bottles and one gallon milk jugs. Garden centers and discount stores carry glass and plastic tubes that can also be used.
Water your plants well one day before you leave. Wash plastic bottles and milk jugs thoroughly.
Fill two-liter bottles and milk jugs with water the night before you leave for vacation. Leave ½ inch head space.
Place one two-liter bottle upside down in the potting soil per outdoor container. Push it at least 2 inches into the potting soil. Pack the soil around the top of the bottle. If your container is large, use a milk jug.
Cover the outdoor containers with plastic drop cloth. Use bricks to hold the edges of the drop cloth in place. This will minimize evaporation from the soil and prevent the watering containers from emptying too quickly.