Growing aloe vera from a leaf can take several weeks to a few months. After cutting a healthy leaf from the plant, it is important to let the cut end dry for a few days to prevent rotting. Once the leaf is ready, you can place it in well-draining soil and water it sparingly. Keep the plant in a location with indirect sunlight and be patient. It may take a few weeks for roots to form, and then new growth will gradually appear. With proper care, the aloe vera plant will continue to grow and thrive over time.