When space is limited in the garden, it is sometimes necessary to be a bit creative. Utilizing old bottles to grow short-term vegetables such as lettuce allows you to grow vegetables indoors or on a balcony. The most effective way is to use the hydroponic method. Hydroponics is a way to grow plants without soil, instead providing the plant the nutrition it needs through a liquid nutrient solution. The plant is held in a soil-less growing medium such as perlite to hold the roots in place and absorb the nutrient solution.
Rinse the bottle so that it is clean to prevent poisoning the new plants says the University of Hawai'i. Rinse several times to remove dish soap. Do not use bleach, as this is harmful to plants.
Cut the plastic bottle at the shoulder so that the mesh pot sits inside the hole without leaving any gaps. A mesh pot is a small pot with holes in the side that allows water to enter and exit; these are available at most garden centers.
Mix the nutrient solution with water according to the dilution rate indicated on the solution's packaging and fill the bottle with the solution. Nutrient solution is a liquid fertilizer available at most gardening centers.
Fill the mesh pot with perlite or vermiculite. Slightly moisten the medium with the hydroponic solution says the University of Arizona, and plant your seeds at the recommended depth.
Place the net pot through the top of the bottle so that the growing medium is in the solution. The pot should cover the hole at the top of the bottle to prevent insects from entering and multiplying in the nutrient solution, warns the University of Hawai'i.
Place the bottle in an area with eight to 12 hours of sunlight, or according to the light requirements of the plant you are growing.
Replace the nutrient solution every four to five weeks.