Celery (Apium graveolens) is a slow-growing biennial crop typically cultivated as an annual, and it is often started indoors due to its lengthy growth cycle. The tiny seeds and slow germination (up to two weeks) make early identification of young sprouts important for successful cultivation. Gardeners must accurately recognize the fledgling plant to avoid accidentally removing it while weeding. Identification begins with the very first leaves that emerge, which look nothing like the mature vegetable.
The First Leaves: Cotyledons
The initial growth above the soil surface consists of the cotyledons, or seed leaves. Celery seedlings emerge with two cotyledons, classifying them as dicots. These structures are extremely small, thread-like, appearing as two tiny, slightly elongated parallel lines of bright green tissue.
These first leaves are not true leaves and do not possess the characteristic shape of the mature foliage. Their primary function is to store nutrients and begin photosynthesis, providing the young plant with energy for establishment. The delicate appearance of these cotyledons can cause new gardeners to easily overlook them or mistake them for a stray blade of grass or a weed.
Appearance of True Leaves
The definitive identification stage begins with the emergence of the true leaves, which develop from the plant’s growing point, or apical meristem, after the cotyledons. The first set of true leaves typically appears several weeks after germination, highlighting the plant’s slow initial growth rate. These structures are the first to resemble the mature foliage, only in miniature.
The true leaves are pinnately compound, meaning they are divided into multiple leaflets arranged on either side of a central stem. This structure gives the foliage a characteristic miniature, fern-like or parsley-like appearance, with lobed and serrated edges. Under strong light, the thin stems may exhibit a slight reddish or purplish coloration, particularly at the base, which is an identifying feature in certain varieties, such as ‘Giant Red’ celery.
Distinguishing Celery Seedlings from Look-Alikes
Differentiating celery seedlings from common weeds relies on observing the fine details of the true leaves and stem structure. Once true leaves develop, celery seedlings maintain a smooth, delicate texture, lacking the fine hairs or rough edges often found on common weed seedlings (such as chickweed or certain clovers). The distinct fern-like structure of the true leaves is a reliable visual cue that contrasts sharply with the rounded or heart-shaped leaves of most weed cotyledons or the simple, unlobed leaves of grasses.
While the intense aroma is a defining feature of the mature plant, a secondary identification tool is the faint celery-like scent released when crushing a true leaf, even in very young seedlings. This aroma, caused by compounds like butylphthalide, is absent in non-celery weeds. Observing the delicate, hairless stem and the unique, miniature, pinnately compound foliage provides the most accurate method for confirming the seedling’s identity.