Cuttings, along with bud grafting, layering and division are all forms of asexual propagation. Asexual propagation produces an exact copy of the original plant. Both herbaceous plants, which die to the ground at the end of the growing season, and woody plants can be propagated through cuttings. Strawberries are particularly easy to propagate through cuttings, because they produce small, individual plants on runners that can easily be used for cuttings.
Use a knife with a sharp blade. This will make it easy to get a clean cut that is less likely to injure the original plant.
Sanitise the blade of your knife before you take the cutting. Use a solution of 1 part bleach to 9 parts water or straight rubbing alcohol to clean the blade.
Cut the runner where it joins the parent plant. There will be a small strawberry plant at the other end of the runner.
Pinch off any blooms or buds that are on the cutting plant. This allows the plant to dedicate its energy to forming a strong, healthy root system.
Dip the bottom of the plant in rooting hormone. Rooting hormone is readily available at gardening centres. It encourages rapid root development, and some types include a fungicide that improves the survival rate of your cuttings.
Plant the cutting in slightly damp, sterile rooting medium. Keep the soil moist and continue to pinch off any buds through the first growing season after cutting. After several weeks the root system should be established well enough that you can transplant the cutting into your strawberry bed.