Petunias are versatile garden plants that look lovely when in bloom. They are also completely edible. Available in nearly every colour, the bloom is used as a garnish for finger foods in some areas. This annual flower is extremely frost resistant and can, if sheltered, spend winter outdoors in some areas. A gardener wishing to propagate petunias can do so by starting them in the early spring from seed or by starting them from a fresh cutting.
Prepare a pot with a mixture of light, porous potting soil.
Pre-moisten the soil. Mix it so that it is moist throughout, but not saturated at any point.
Cut a section of green growth from the parent plant. New growth will work best. The cutting should be 5 to 7.5 cm (2 to 3 inches) long, taken from directly below a leaf node. A good cutting will include three to six nodes. A node is the point from which a plant leafs and is often just a little bump on the stem if leaves have not yet emerged from it.
Remove all but three or four of the leaves. These leaves should be left at the very top of the cutting.
Remove any flower buds or seeds from the cutting. These elements will sap large amounts of energy from the cutting if they are allowed to remain; removing them ensures that the plant can grow a healthy rooting system.
Prepare two more cuttings in the same way.
Place three cuttings into the prepared pot. About 2.5 cm (1 inch) of the cutting should be placed below the soil.
Pack the soil tightly around the cutting. Compact the soil to remove all air pockets.
Water the cuttings thoroughly after they are set.
Place the pot in a window that does not receive direct sunlight or outside in the shade.
Allow two weeks before you start checking the roots. If you intend to move flowers to an outdoor garden or a different pot, the plants are ready for transplanting when the roots reach a length of 2.5 cm (1 inch).