Whether you are watering outdoor garden plants or indoor potted plants, using milk jugs allows for a slow continuous watering that is beneficial to both the plant and the soil. When water is available in the form of a fast, hard rain, less water penetrates into the soil. Slow applications of water allow the plant's roots to absorb more water to maintain growth and sustenance. Watering plants with milk jugs is also an excellent "green" option for using plastic containers.
Using a funnel, fill a milk jug with sand and place the cap on the top of the jug. If the cap is not present, hold your hand over the top to prevent the sand from spilling out.
Using the nail and hammer, poke several holes (about five to seven) in one side of the bottom of the milk jug. The holes should be relatively close together and nearest the outside edge of the bottom of the milk jug. Additionally, the smaller you make the holes, the more water will be absorbed by the plant.
Continue filling milk jugs with sand and poking holes until all the milk jugs you plan to use for watering are completed.
Fill the watering jugs with water, holding your hand over the area with holes, and set the jug as close to the plant as possible without disturbing stems or growth. The side of the jug that has the holes punched in it should be closest to the base of the plant.
Allow jugs to empty on their own, preferably in the late evening or overnight.