How to Grow Oregano Indoors

Growing oregano (Origanum vulgare) indoors offers convenience for picking and protects plants from poor weather and most pests. Providing aromatic leaves for the kitchen and potpourris, oregano grows outdoors in U.S. Department of Agriculture plant hardiness zones 4 through 9, and grows best in a full-sun site. It requires a period of adjustment to indoor light levels and can die if moved directly indoors from a sunny spot. When growing indoors, oregano requires supplemental lighting for healthy growth. A variable herb, oregano varieties grow 12 to 24 inches tall and 10 to 20 inches wide, and bear tiny, tubular, purple, pink or white summer flowers.

Plant pots with drainage holes

Well-draining potting soil

Fluorescent light or 400-watt metal halide lamp

24-8-16 fertilizer

Fill a terra cotta plant pot that's large enough to just accommodate the root ball with well-draining potting soil, such as an equal mix of peat moss and sand.

Place oregano growing outdoors in a partly shady spot for two to three weeks to prepare it for moving indoors. Place the pot in a spot in full shade for a further two to three weeks. Move the pot indoors when new growth appears.

Place oregano 8 to 10 inches below a fluorescent light or 3 feet below a 400-watt metal halide lamp for 10 to 16 hours each day.

Water actively growing oregano when the soil surface is dry, applying water until it runs through the drainage holes. Allow the plant to drain thoroughly before returning it to its drip tray. Reduce watering in winter when growth slows or stops, and apply water when the soil is dry 1 inch below the surface.

Mix 1/2 teaspoon of water-soluble 24-8-16 fertilizer with 1 gallon of water or follow the manufacturer's instructions. Water the oregano with the solution once every two weeks when it is actively growing.

Repot your oregano plant if you notice its roots growing out the drainage holes of the original pot or if you have to moisten the potting soil more frequently. Tap the original pot gently on a hard surface to loosen the root ball, remove the oregano plant and place it in a pot that's about 1 inch larger in diameter than the original. Fill in the gaps with potting soil and add water until it runs through the drainage holes.

Harvest oregano leaves when the plant is 6 inches tall by pinching off the desired number of leaves with your thumb and forefinger. Sterilize your pruning shears by wiping the blades with rubbing alcohol; then remove the top one-third of growth in June if the plant is growing vigorously. Sterilize the pruning shears again after use.

If you're unable to provide artificial lighting for the oregano plant, place it on a south-facing windowsill indoors and rotate the pot 180 degrees every two or three days to promote even growth.

If you're using a light, add a timer to the outlet so you don't have to remember to turn the light on and off each day.