Rhubarb is a unique perennial vegetable, often utilized in the kitchen as a fruit because of its distinctly tart flavor. It is one of the first garden crops to appear in spring, making it a highly anticipated addition to early-season cooking. However, understanding the correct time and method for harvesting rhubarb is crucial for the plant’s health and the safety of the consumer.
Only the leaf stalks, or petioles, are edible. The large, fan-shaped leaves contain high concentrations of oxalic acid and anthraquinone glycosides, making them toxic. Ingesting the leaves can lead to symptoms like kidney damage, nausea, and difficulty breathing, so they must be removed and discarded immediately after harvesting the stalk.
The Critical First Year Rule
Harvesting rhubarb too early can severely weaken the plant. When a rhubarb crown is first planted, it needs an entire season to establish a robust root system. These roots are the plant’s energy reservoir, necessary for long-term health and productive harvests for years to come.
A new rhubarb planting should not be harvested at all during its first growing season. If the plant is exceptionally vigorous and was planted early in the spring, a gardener may take one or two small stalks very late in that first season. Patience is rewarded, as it ensures the plant can sustain heavy harvesting later. By the second year, a light harvest for three to four weeks may be taken, with a full harvest commencing in the third year.
Seasonal Timing and Stalk Readiness
The annual rhubarb harvest window typically begins in early spring, usually in April or May, depending on the climate. This is when temperatures rise and the stalks rapidly emerge, becoming plump and tender. The best way to determine readiness is not by the calendar but by the stalk’s size and appearance.
Stalks are ready to harvest when they are firm and approximately 7 to 18 inches long. If the stalks appear thin or spindly, it is a sign that the plant’s energy reserves are low, and harvesting should be paused or avoided entirely. The color of the stalk (red, pink, or green) is determined by the variety and does not indicate ripeness or flavor.
Proper Harvesting Technique and Quantity
To maintain the health of the perennial crown, pull and twist the stalk, rather than cutting it with a knife. Grasp the stalk near its base and pull it firmly to the side with a gentle twisting motion until it separates cleanly from the crown. This ensures the stalk is fully removed, preventing a small stub from being left behind.
Leaving a stub creates an entry point for pests and diseases, and the remaining tissue can decay, increasing the risk of crown rot. Never remove more than one-third to one-half of the plant’s stalks at any given time. Leaving sufficient foliage is necessary for photosynthesis, allowing the plant to replenish energy stores for the following season.
The harvest season must conclude by mid-summer, typically late June or early July. As temperatures increase, the stalks become less palatable, developing a tougher, woody texture. Stopping the harvest allows the plant to focus energy on storing carbohydrates in the roots, preparing it for winter dormancy and ensuring a plentiful crop the next spring.