Growing Nepeta cataria, commonly known as catnip, indoors is a forgiving project for any herb enthusiast or cat owner. The plant is a member of the mint family and is naturally vigorous. Cultivating catnip in a container indoors is often the preferred method, as its outdoor growth habit can be aggressive and invasive due to prolific self-seeding. Growing it inside allows for year-round access to fresh leaves and provides a controlled environment.
Starting Your Indoor Catnip
The initial setup requires a container with adequate drainage holes, as this herb is highly susceptible to root rot. Terra-cotta pots are often recommended because their porous nature helps wick away excess moisture from the soil. The ideal planting medium is a high-quality, well-draining potting mix, such as a slightly sandy blend to mimic its natural preference for drier conditions. Drainage can be enhanced by incorporating perlite or coarse sand.
Catnip can be started from seeds, which sometimes require stratification to encourage germination, or from an established cutting. Starting from a cutting or purchasing a small transplant offers a much quicker path to a mature plant. To start from a cutting, select a healthy stem of new growth, remove the lower leaves, and place it directly into the prepared potting mix or water until roots form. This method establishes a new plant more efficiently than seeds.
Optimizing the Growing Environment
Catnip thrives when it receives a substantial amount of light, which is the most significant factor for successful indoor growth. The plant requires a minimum of six to eight hours of direct light daily to maintain a dense shape and maximize the production of its aromatic oils. A sunny, south-facing window is the best natural location, but supplemental artificial light may be necessary during winter months.
If natural light is insufficient, supplementing with full-spectrum LED or fluorescent grow lights is necessary to prevent the plant from becoming “leggy.” Lights should be set on a timer to provide a consistent 14 to 16 hours of light exposure per day. The ideal indoor temperature range for catnip is between 65 and 75 degrees Fahrenheit, aligning well with typical household temperatures.
Proper watering technique is crucial to avoid root rot. Only water the plant once the top inch of soil has become dry to the touch, then water thoroughly until it drains from the bottom of the pot. Good air circulation is also important; moderate humidity levels are preferred, but stagnant air can encourage fungal diseases like powdery mildew.
Sustaining Growth and Harvest
Regular pruning is necessary to maintain a bushy plant and encourage continuous new growth, which is more potent than older foliage. Once the plant reaches about six to eight inches in height, pinch or snip back the growing stems and any flower buds that appear. This practice prevents the plant from putting energy into seed production and keeps the leaves concentrated with the nepetalactone compound.
Indoor catnip is generally hardy but can occasionally attract common houseplant pests like spider mites or aphids. A non-toxic approach to pest control is recommended, such as gently wiping the leaves with a damp cloth or using an insecticidal soap or neem oil spray. Consistent inspection of the underside of leaves helps catch any small infestations before they can spread.
The best time to harvest catnip for maximum potency is when the plant is just beginning to flower, as this is when the concentration of essential oils peaks. Use clean shears to cut entire stems, leaving a few inches of growth on the plant to encourage quick regrowth. The harvested leaves and flowers should be air-dried in a cool, dark, and well-ventilated area for one to two weeks, then stored in an airtight container to preserve their aromatic qualities.