One or more nurseries are present in Pittsburgh. A nursery or a plant nursery is the place where plants are grown and propagated, usually for sale. These nurseries are primarily for retail sales. The nurseries usually grow the plants in the greenhouse. The plants reared themselves can also vary widely. These nurseries are also important in branches of agriculture, forestry and conservation biology. The sales may be seasonal in nature. Ornamental or garden plants are usually the most popular items for sale in Pittsburgh. The plants are propagated asexually by budding, grafting, layering, or other nursery techniques. They may also be sent by mail to the customers, in the form of cuttings or seedlings.