Select a healthy, vigorous stem for propagation. The plant should be disease-free and of a variety known to produce good-quality fruit, if desired. For fruiting, both male and female varieties must be propagated.
Using hand pruners, take cuttings that are between one-eighth and one-quarter of an inch in diameter and about 4 inches long. Each cutting needs to have at least two leaf nodes -- the raised bumps along the stem that leaves grow from.
Remove all but the topmost leaf from each cutting with the pruners. Cut the top leaf in half to further reduce the amount of moisture that can evaporate from the leaf surface. This helps to prevent the cutting from drying out before roots have formed.
Stick the cutting in a moistened rooting medium of perlite or vermiculite in a gallon-size plastic pot. Leave at least one leaf node below the level of the rooting medium -- where the roots will grow -- and one above -- where the leaves will grow. Up to four cuttings can be rooted in each pot.
Using a utility knife, cut a 2-liter plastic bottle in half to use as a cover for the cuttings. Place the top half over the cuttings, and push down slightly into the perlite. This will hold heat and moisture around the cuttings.
Open the top of the plastic bottle every few days, and spray the leaves with a fine mist from a spray bottle. Keep the cuttings in indirect light in a warm location until roots have formed.