Catnip (Nepeta cataria) is a perennial herb in the mint family, Lamiaceae. Known for its stimulating effect on many felines due to the compound nepetalactone in its leaves, this aromatic plant is native to Europe and Asia. It typically grows 2 to 3 feet tall and wide, forming a bushy habit. Beyond attracting cats, catnip also draws beneficial pollinators like bees and butterflies, making it a versatile garden addition.
Planting Catnip
Catnip can be started from seeds, cuttings, or starter plants. For seeds, cold stratification (freezing overnight, then soaking in water for 24 hours) can improve germination. Sow seeds about 1/8 inch deep in a seed-starting mix, keeping the soil moist until germination, usually within two weeks.
For cuttings, take 4 to 6-inch stem pieces, remove lower leaves, and place them in water or moist soilless potting mix. Roots typically appear within a week, and the cutting is ready for transplant once new foliage grows.
When transplanting seedlings or starter plants, space them 18 to 24 inches apart for proper growth and air circulation. Catnip spreads aggressively, so planting it in a container or raised bed can help manage its growth if grown directly in the ground. For indoor plants, choose a container with drainage holes, at least 8 to 10 inches wide and deep. Plant catnip outdoors in spring after the last frost.
Ongoing Catnip Care
Light Needs
Catnip thrives in full sun, needing at least six hours of direct sunlight daily. Insufficient light leads to leggy growth and sparse foliage. In regions with intense summer heat, afternoon shade can prevent heat stress or scorched leaves. For indoor plants, place them near a sunny window with ample direct light.
Soil Requirements
Catnip is adaptable and tolerates various soil types, provided they offer excellent drainage. It can grow in poor, rocky, and dry soils, but thrives best in well-draining sandy or loamy soil. An ideal soil pH ranges from slightly acidic to slightly alkaline, between 6.0 and 7.8. Incorporating compost during planting enhances soil quality and provides initial nutrients.
Watering Frequency
Once established, catnip is drought-tolerant, preferring well-draining soil. Overwatering causes root rot. Water about once a week, allowing the top inch of soil to dry completely between sessions. Adjust frequency based on seasonal conditions, increasing it during hot, dry periods and reducing it in cooler months.
Temperature and Humidity
Catnip grows well in temperatures from 55 to 85 degrees Fahrenheit (13 to 29 degrees Celsius). It struggles with extreme heat and high humidity. In humid climates, ensure good air circulation to reduce fungal growth risk. Catnip tolerates cold temperatures down to -22 degrees Fahrenheit, but prolonged freezing can cause damage.
Fertilizing
Catnip has low nutrient requirements and needs minimal fertilizing. Mixing compost into the soil at planting provides an initial nutrient boost. If soil quality is poor, or to encourage growth, apply a light balanced liquid fertilizer (e.g., 10-10-10 NPK) in spring. Fertilize sparingly; excessive fertilization can reduce the oil content that attracts cats and may lead to burnt roots.
Harvesting and Pruning Catnip
Harvest catnip leaves and stems when the plant reaches 12 to 18 inches tall, ideally on a dry morning when oil levels are highest. Cut the entire plant at the base or trim stems just above a leaf node to encourage new growth. To dry, bundle stems and hang them upside down in a well-ventilated, dark area away from direct sunlight for one to two weeks, or use a dehydrator on a low setting. Once dried, store catnip in freezer bags to preserve its aromatic oils.
Regular pruning promotes bushier growth and prevents legginess. Pinching back young plants or trimming the top one-third encourages side shoots and denser foliage. After the first bloom, pruning can encourage a second flowering. Deadheading (removing spent blooms) stimulates continuous flowering and prevents aggressive self-seeding. In fall, after the first frost, cut mature plants back to a few inches from the soil for spring regeneration.
Common Catnip Problems
Catnip is a robust plant, but it can encounter some common issues. Pests like spider mites, aphids, thrips, whiteflies, and flea beetles may affect it. Spider mites are identified by fine webbing and tiny black spots, causing leaves to appear dry and yellow. Aphids are small, sap-sucking insects that can stunt plant growth.
Catnip’s strong scent can deter some pests, making it a companion plant for certain vegetables. Solutions include washing them off with a strong water jet or using insecticidal soap. Fungal diseases like Cercospora leaf blight cause small flecks with yellow halos on leaves, leading to browning and plant decline. Good air circulation and avoiding overwatering help prevent fungal issues.