Guavas (Psidium guavaja) are delightfully aromatic, tropical fruit produced on low-maintenance trees. They tolerate minimal frost and can be grown in U.S. Department of Agriculture plant hardiness zones 10 through 12. Guavas are easy to grow and propagate themselves to excess in some areas -- they are considered invasive in parts of Florida and Hawaii. The easiest way to grow guavas at home is from the cuttings of another tree.
Select a healthy tree of known fruit quality to propagate. Straight, vigorous branches have the highest success rates when used for cutting material.
Make cuttings about 6 inches long from wood that is 1/4 to 1/2 inch in diameter.
Remove all but the top two leaves from each cutting. Cut the top two leaves in half to reduce moisture loss while the cutting is forming roots.
Fill gallon-size pots with a sterile rooting medium such as perlite, and wet it down thoroughly. Plan on one pot for every four cuttings.
Dip the bottom half of the cuttings into rooting hormone, and stick them halfway down into the rooting medium.
Cut a 2-litter bottle in half, and place it over the cuttings inside the pot with the lid facing up. Push the bottle down an inch or so into the rooting medium to trap air and moisture around the cuttings.
Place the potted cuttings in bright, indirect light in a location where they will stay as warm as possible day and night -- 75 to 85 degrees Fahrenheit is ideal for stimulating root formation.
Open the lid of the plastic bottle, and spritz the cuttings with water. Repeat every two or three days until roots have formed. When the cuttings begin to grow new leaves from the top, sufficient root formation has occurred and they can be transplanted to individual pots.