Oregano needs only a moderately fertile soil to thrive in, though drainage and friability are important. Plant outdoors 12 inches apart after all danger of frost has passed. Plants are easily started from seed, stem cuttings, or mature root division.
Oregano appreciates being hoed regularly and neighboring weeds should be kept under control. Mulching with hay helps keep plants clean outdoors. Oregano lends itself well to container and hydroponic methods of cultivation.
When flowers appear, oregano is ready to be harvested, unless continuous picking of leaves during growth prevents flowering. About six weeks after planting, trim oregano shoots to within one inch of the center which will stimulate lush, bushy growth.
Oregano usually grows to a height of 12 to 18 inches (30 - 45cm).
Oregano plants should be spaced between 12 and 15 inches (30 and 38 cm) apart.
Preferred pH Range
Oregano will grow in a pH range between 6.0 (mildly acid) and 9.0 (strongly alkaline) with a preferred range between 6.0 and 8.0.
Sow direct in spring when soil temperature is at least 15 degrees C; or sow in starter cubes or plugs 6 weeks before field planting; or sow indoors six weeks before last frost.
Seed Germination Period
Oregano seeds will germinate in soil in approximately 8 to 14 days.
Oregano thrives in well-drained, sandy, and relatively dry soils.
Sun & Lighting Requirements
Oregano grown outdoors prefers full sun.
Oregano will grow indoors satisfactorily under standard fluorescent lamps, and exceptionally well under high output T5 fluorescent plant lights, compact fluorescent, or high intensity discharge (metal halide or high-pressure sodium) plant growing lights. Keep standard fluorescent lamps between 2 and 4 inches from the tops of the plants, high output and compact fluorescents approximately one foot above the plants, and HID lights between 2 and 4 feet above the plants, depending on wattage.
Have an oscillating fan gently stir seedlings for at least 2 hours per day to stimulate shorter, sturdier, and more natural plant habit.
Water regularly, being careful not to overwater. Allow soil to go completely dry between waterings.