Keeping houseplants watered while you are away is always a concern for plant lovers. Although you may be able to get a friend to stop by and water the plants, that requires giving someone else access to your home and arranging for keys to be exchanged. Making an inexpensive watering system for your plants from plastic pop bottles allows you to take care of your plants without the security risks that come from having others enter your home when you are not there. The same system can also be used to reduce plant care duties on a regular basis.
Wash and dry the soda bottles. For very large plants, you can use a 2-liter bottle, but for most plants in small-to-medium pots, a 20-oz. bottle is ideal.
Remove the label with scissors or a sharp knife. Remove any residue left behind by washing the area with a scrub brush. If it is difficult to remove, allow the bottle to soak in warm, soapy water for 20 minutes and scrape the remaining glue from the bottle with a knife.
Mark a line around the bottle 2 inches from the bottom. Cut the bottom off the bottle, following your marking. Use a sharp knife or puncture the bottle and cut with scissors. Discard the bottom of the bottle.
Place the cap on the bottle. Drill four 1/4-inch holes evenly spaced around the neck of the bottle, approximately 2 inches from the cap. Add 2 or more holes to the cap, if desired. The Oklahoma State University extension Office recommends four holes in the bottle to provide a slow release of water. More holes cause water to release into the soil more rapidly.
Insert the bottle into the soil in the plant pot so that the holes rest beneath the soil level. Submerge the bottle up to the cut rim if you like. If you intend to use the bottle for watering on a regular basis, submerging the bottle to the cut rim improves appearance.
Fill the bottle with water. The water will gradually drip into the soil, keeping soil moist. Refill the reservoir regularly to provide a constant source of water.