Rosemary (Rosmarinus officinalis) is a Mediterranean herb that thrives in warm, sunny, and dry conditions. In its native environment, it grows in well-drained, sandy or rocky soils with plenty of sunlight. When growing rosemary indoors, it’s essential to replicate these conditions as closely as possible. The plant prefers temperatures between 60-75°F (15-24°C) and dislikes high humidity or overly wet soil, which can lead to root rot.
Rosemary requires a container with excellent drainage to prevent waterlogging. A terracotta or clay pot with drainage holes is ideal because it allows excess moisture to evaporate. Use a lightweight, well-draining potting mix, such as a cactus or succulent blend, or amend regular potting soil with perlite or coarse sand to improve drainage. Avoid heavy, moisture-retentive soils, as they can suffocate the roots.
As a sun-loving plant, rosemary needs at least 6-8 hours of direct sunlight daily. Place it near a south-facing window where it can receive the most light. If natural light is insufficient, supplement with a grow light positioned 6-12 inches above the plant for 12-14 hours a day. Insufficient light will cause leggy growth and weaken the plant.
Rosemary prefers to dry out slightly between waterings. Overwatering is a common mistake—wait until the top inch of soil feels dry before watering again. When watering, soak the soil thoroughly until water drains from the bottom, then empty the saucer to avoid standing water. Reduce watering frequency in winter when growth slows.
Indoor environments, especially in winter, can be too humid for rosemary. Ensure good air circulation by placing the plant in a well-ventilated area or using a small fan. Avoid misting the leaves, as this can promote fungal diseases. If your home is very dry, a pebble tray with water beneath the pot can provide slight humidity without over-saturating the soil.
Rosemary is not a heavy feeder, but occasional fertilization can support growth. Use a balanced, water-soluble fertilizer diluted to half strength every 4-6 weeks during the growing season (spring and summer). Avoid fertilizing in fall and winter when the plant is dormant, as this can lead to weak, spindly growth.
Regular pruning encourages bushier growth and prevents the plant from becoming woody. Trim the tips of the stems by 1-2 inches every few weeks, focusing on new growth. Avoid cutting into old, woody stems, as they may not regrow. Harvesting sprigs for culinary use also doubles as pruning.
Indoor rosemary is susceptible to pests like spider mites, aphids, and whiteflies. Inspect the plant regularly and rinse pests off with a gentle spray of water or treat with insecticidal soap. Prevent fungal issues by avoiding wet foliage and ensuring proper airflow. If root rot occurs due to overwatering, repot the plant in fresh, dry soil and trim affected roots.
Rosemary can be propagated from cuttings for new plants. Take a 3-4 inch cutting from a healthy stem, remove the lower leaves, and dip the end in rooting hormone. Plant it in moist, well-draining soil or place it in water until roots develop. Keep the cutting in bright, indirect light and maintain consistent moisture until established.
In winter, rosemary may enter a dormant phase with slower growth. Reduce watering and avoid fertilizing during this time. If temperatures drop below 50°F (10°C), protect the plant from drafts or cold windows. In spring, resume regular care and consider repotting if the plant has outgrown its container.
