Rosemary (Rosmarinus officinalis) features highly fragrant, evergreen foliage that delights the eye and the taste buds. This perennial herb grows in U.S. Department of Agriculture plant hardiness zones 8 through 10, but you can enjoy rosemary any climate by growing it in a pot indoors. Rosemary often declines quickly indoors because of dry air and minimal sun. Keeping the plant alive requires special attention to both the growing location and basic plant maintenance.
Plant rosemary in a pot that has at least one bottom drainage hole so excess water can drain freely from the soil. Use a standard soilless potting medium that drains well but doesn't dry out too quickly.
Set the pot near a window that receives all-day, direct sunlight. Avoid locations near heat vents because the dry air can damage or kill the plant. A cool, slightly humid location provides for the healthiest indoor growth. Create humidity by spraying the plant weekly with water.
Feel the soil in the pot every two to three days. Water the rosemary when the top 1 inch of soil just begins to feel dry, but before the soil dries out completely. Allow the water to drain from the bottom of the pot for about 30 minutes after each irrigation, and then empty the excess water from the drip tray.
Apply a soluble all-purpose fertilizer every two weeks. Dissolve 1/4 teaspoon of a 24-8-16 or similar fertilizer in 1 gallon of water. Water the rosemary with this solution to provide additional nutrients.
Pinch back the top 1 inch of each stem in spring when active growth resumes. Pinching encourages branching and a fuller plant. Cut back the plant by 1/3 of its height in summer after it finishes flowering.