Culinary oregano is a signature flavor of many Italian, Mexican and Spanish dishes, and you can easily grow it in the home garden to use for cooking. Growing oregano is easy! Plants can be started from seeds, divisions or cuttings.
Oregano seeds require some light to germinate, so cover only slightly with soil. Start seeds indoors and transplant when temperatures remain above 45 degrees F. Oregano is one of those ‘Mediterranean’ herbs that like well-drained soil, on the lean side, and full sun. Divide plants when the centers begin to die out or the stems become too woody. You can also divide plants simply to make more plants. Once the plant has reached 4-5 inches tall, you can start cutting sprigs for use. Harvesting before the plant blooms will yield the most flavorful leaves. You can begin harvesting when plants have reached 4-5 inches in height. Cutting stems all the way back to the ground will encourage more stems and a fuller plant.
SOURCE:http://www.gardenoholic.com/grow-care-oregano-garden/