The herbaceous perennial Nepeta cataria, commonly known as catnip, is widely recognized for the euphoric effect it has on felines and is also used in herbal remedies for its calming properties. This member of the mint family, native to Europe and Asia, produces fragrant foliage and small flowers. Cultivating this plant begins with understanding its reproductive structure, which means recognizing its seeds.
Visual Characteristics of Catnip Seeds
Catnip seeds are diminutive, generally measuring between 1 and 2 millimeters in length. They are small enough that a single flower head can yield many. When fully mature and dried, the color typically ranges from dark brown to black.
They possess a distinctive shape, often described as oblong or teardrop-like, and are sometimes slightly flattened. This shape distinguishes them from perfectly round seeds.
The seeds develop inside small, three-sided fruit structures called nutlets. These nutlets form after the small, typically white or lavender, flowers have finished blooming. The texture of the individual seeds is generally smooth or only very slightly ridged.
Locating and Collecting Seeds
Catnip seeds are produced within the spent flower spikes that form along the upper stems of the plant. To successfully locate them, a gardener must wait until the plant has finished flowering and the seed heads have completely dried out. The clusters of flowers, which were once soft and colorful, will have turned brown and become brittle.
The seeds are held securely within the dried calyxes. This drying and browning process signals that the seeds inside have matured and are ready for harvest. Collecting them involves carefully cutting the dried flower stalks and placing them into a paper bag or container.
To extract the seeds, the dried flower heads can be gently shaken inside the bag, causing the minute seeds to fall out. Alternatively, the dried material can be lightly crushed by hand to fully release the contents. This yields the small, dark seeds mixed with dry plant material, which then needs to be winnowed out.
Key Steps for Successful Germination
Catnip seeds often possess a natural dormancy that requires specific conditioning to ensure reliable sprouting. The most effective method for breaking this dormancy is a process called cold stratification, which simulates the natural conditions of winter.
One way to achieve stratification is to place the seeds in a damp paper towel or a small amount of moist sand and refrigerate them for a period of two to six weeks before planting. Alternatively, a shorter treatment involves freezing the seeds overnight, followed by a 24-hour soak in water. This preparation significantly improves the rate of successful germination.
When planting, catnip seeds should be sown very shallowly, as they require light to germinate effectively. The recommended planting depth is often no more than an eighth of an inch, meaning the seeds should be barely covered with soil. A well-draining soil mix is preferred, as catnip naturally thrives in conditions that prevent waterlogging.