Rosemary thrives best in soils rich in alkaline and is especially respondent to lime. If your rosemary is drooping or losing leaves, add some lime juice to the soil and it will rejuvenate itself. It does not respond well to commercial fertilizers and should be fed only a slow-release type of plant food once a year. Use a light, sandy soil and keep it well drained.
Many rosemary plants fail from overwatering. Keep the soil dry to the touch on the surface and water it only when it becomes dry about 2 inches deep. Avoid growing rosemary in outdoor gardens in regions with heavy rainfall. Use plant sticks that indicate soil water levels to accurately monitor the moisture in the soil.
While rosemary can withstand hot and dry periods, it does not grow well in humid climates, extended freezing temperatures or high winds. A sheltered sunny location is perfect for growing rosemary. Rosemary grown outdoors should be planted in a garden area that is protected from the wind by other plants or other obstructions. Indoor rosemary plants grow best in areas free from fans, vents or air ducts.
A little rosemary goes a long way in recipes, so if you harvest only what you need and readily remove dead branches, one plant will normally provide enough rosemary leaves to meet your culinary needs for life. If you are growing rosemary in your garden, carefully dig up the plant each season and reposition it, as it thrives best when rotated in soils enriched by nutrients from other garden plants. To control overzealous rosemary plants, cut them back right after they flower.
Rosemary is easy to propagate, so if you are having problems with it dying, use several healthy cuttings from a healthy salvaged plant or donated by a friend and plant them in different types of pots. The cuttings normally take root within a few days. Experiment with soils that have varying alkaline levels and expose the plants to areas that get different amounts of sunshine.