Celeriac, often called celery root, is a variety of celery cultivated for its swollen, subterranean stem base rather than its stalks. Despite its gnarled exterior, the flesh offers a refined, nutty, and earthy flavor with subtle notes of celery and anise. Knowing when to harvest this slow-growing root is important, as timing directly influences its sweetness, texture, and ability to keep well in storage.
Signs the Celeriac is Ready
Celeriac is a long-season crop, requiring 90 to 120 days after transplanting to reach maturity. The ideal harvest window usually opens in the late fall, around October or November. The primary cue for readiness is the size of the root, which should be approximately three to five inches in diameter.
Harvesting at the correct size prevents the root from becoming woody or hollow. A slight yellowing of the outer foliage can signal that the plant is directing its final energy reserves into the root. Exposure to a light frost is beneficial for flavor development.
Light frost triggers a natural conversion process within the root, changing starches into sugars and resulting in a sweeter taste. However, a heavy or deep freeze will damage the root structure, causing it to crack or rot, which ruins its texture and storage potential. The goal is to harvest shortly after the first light frost but before the ground freezes solid.
Techniques for Safe Removal
Once the celeriac has reached the desired size, harvesting must be executed carefully to avoid damaging the edible bulb. Celeriac anchors itself firmly in the soil with a tight mass of feeder roots. The root cannot simply be pulled out by the green stalks, as this will likely cause the stalks to snap, leaving the root stuck.
The proper method involves using a garden fork or spade to gently loosen the soil, known as undermining. Insert the tool several inches away from the root on all sides, pushing down to break the surrounding soil and sever the fine feeder roots. This action releases the tension holding the root in place.
After the soil is loosened, carefully lever the entire plant out of the ground, taking care not to puncture or bruise the bulb. Any significant damage to the root during lifting will create entry points for pathogens, leading to rapid decay and making it unsuitable for long-term storage.
Cleaning and Trimming After Harvest
Immediately after lifting, the roots must be prepared for either immediate use or preservation. First, gently brush off any large clumps of excess soil clinging to the bulb. Avoid washing the root at this stage, as introducing external moisture significantly increases the risk of mold and bacterial rot during storage.
Next, the green foliage and stalks need to be trimmed back to focus the plant’s energy on the root and reduce moisture loss. Use a sharp knife to cut the stalks down to about a half-inch above the crown. Simultaneously, the fine rootlets extending from the bottom of the bulb should be trimmed close to the surface.
Any roots that were nicked or bruised during removal should be set aside and consumed within a few days. Only perfectly intact, undamaged bulbs should be designated for the long-term storage process to maximize shelf life.
Maximizing Freshness Through Proper Storage
To maintain the celeriac’s quality, the storage environment must mimic the cool, moist conditions of late fall soil. Ideal conditions are a temperature near freezing, specifically between 32 and 40 degrees Fahrenheit, combined with high humidity (90 to 95 percent). These requirements slow the root’s respiration and prevent dehydration.
For long-term preservation, celeriac stores well in a traditional root cellar or a cold, dark basement. The trimmed roots should be layered in a container filled with a damp medium, such as moist sand, peat moss, or sawdust, which helps maintain high humidity. Under these cold, damp conditions, the roots can remain fresh and firm for three to six months.
For shorter storage of one to two weeks, the trimmed roots can be placed in a perforated plastic bag inside the refrigerator crisper drawer. The plastic helps retain moisture, while the perforations prevent the buildup of ethylene gas, which can accelerate spoilage.