Sunchokes, also known as Jerusalem artichokes, are the edible tubers of a sunflower species, Helianthus tuberosus, prized for their subtle, nutty, and slightly sweet flavor. They are easy to cultivate and thrive in various soil conditions, making them a popular choice for home gardeners. The quality and flavor of the harvest depend on the timing and method of extraction, as the tubers’ thin skin makes them prone to moisture loss once removed from the soil.
Optimal Timing for Harvesting Sunchokes
The flavor of sunchokes is primarily influenced by the timing of the harvest, which should occur after the first hard frost of the year. Low temperatures trigger a biological process within the tuber, converting starches into fructose, a simple sugar. This conversion enhances the sweetness of the sunchokes and is also believed to improve their digestibility.
After a substantial frost, the plant’s tall, leafy stalks will naturally die back and turn brown, signaling that the plant’s energy has been redirected to the underground tubers. The tubers are best left in the ground until needed, as the soil acts as the most effective natural storage mechanism, protecting them from drying out. In regions where the ground does not freeze solid, sunchokes can be harvested from late autumn through early spring, digging them up only as required.
Preparing the Plants for Digging
Before digging, the tall, woody stalks must be cut back to clear the workspace and identify the tuber location. Using sharp shears, cut the stalks down to four to six inches above the soil line. This short stub serves as a clear marker for the plant’s base, which is necessary because the tubers spread well beyond the central stalk.
Removing the dead plant matter prevents interference with the digging process and allows better access to the soil. Wait until the stalks are completely dry and brittle, indicating that the plant has finished transferring energy to the roots, to ensure clean and efficient tuber extraction.
Techniques for Extracting the Tubers
The physical act of harvesting must be done carefully to avoid damaging the knobby, irregularly shaped tubers, which are brittle and bruise easily. A digging fork or pitchfork is the preferred tool over a spade, as the tines minimize the chance of slicing through the tubers. The sunchoke root system spreads widely and often relatively shallowly, sometimes extending eighteen inches or more from the main stalk.
Insert the fork into the soil at least eighteen inches away from the remaining stalk stub, digging deeply before gently prying the soil and root mass upward. This technique is designed to lift the bulk of the tubers without impaling them. After lifting the main clump, search the surrounding soil by hand or with the fork, as many individual tubers spread far from the main plant.
To ensure a continuous supply, leave a few smaller, unblemished tubers in the ground for regrowth. Sunchokes are highly prolific, and even a small, overlooked tuber is enough to start a new plant the next spring. Selectively leaving some behind prevents overcrowding while guaranteeing a perpetual yield.
Cleaning and Storing the Harvest
Once harvested, the tubers do not require a curing period like potatoes. They must be handled quickly to preserve their moisture content. The thin skin causes sunchokes to lose hydration and shrivel quickly if left exposed to the air. Immediately brush off the majority of the clinging soil after harvesting, but do not wash them with water, as this accelerates spoilage.
For long-term storage, maintaining a cool temperature and high humidity is key to counteract the thin skin. Place the unwashed tubers in a perforated plastic bag or an airtight container layered with a slightly dampened material, such as peat moss or sand. This container should then be stored in the coldest section of a refrigerator or a root cellar, ideally near a temperature of 32–36 degrees Fahrenheit. If stored properly in this cool, moist environment, sunchokes can retain their freshness for several months.