Rhubarb is a hardy, long-lived perennial vegetable often used as a fruit. Its ability to return year after year makes it a valuable addition to any garden. Achieving consistent production depends greatly on proper planting technique, particularly the depth at which the root structure is placed. Ensuring the crown is not buried too deeply is important for establishing a healthy, productive plant.
Site Selection and Soil Preparation
Rhubarb thrives in full sun, meaning at least six hours of direct sunlight daily, though it tolerates light afternoon shade in hotter climates. Since it is a permanent fixture, choose a dedicated space away from annual vegetables. The plant grows large, often reaching two to four feet in height and width, so proper placement is necessary to avoid crowding.
The most important soil requirement is excellent drainage, as the fleshy crown is susceptible to rot in soggy conditions. While it performs best in a slightly acidic to neutral pH range (6.0 to 6.8), the soil must be rich in organic matter. Rhubarb is a heavy feeder, requiring a continuous supply of nutrients to produce large stalks and leaves.
Before planting, the soil should be prepared deeply, ideally to a depth of at least 12 inches, to accommodate the extensive root system. For heavy clay or poor soils, amend the site with substantial amounts of aged manure or finished compost to improve structure and drainage. This initial effort in soil enrichment is beneficial for long-term plant health, as the plants will remain in this location for many years.
Planting Rhubarb Crowns
The best time to plant rhubarb crowns is in early spring, as soon as the soil is workable and the roots are dormant, or in late autumn after the foliage dies back. Planting crowns (root divisions from a mature plant) is the most common method and provides a quicker path to harvest than growing from seed. Dig a wide planting hole, about 12 inches deep and 12 inches wide, to comfortably spread out the roots.
The definitive instruction for planting depth is to ensure the growing buds, or “eyes,” are covered by only a shallow layer of soil. Position the crowns so the top of the bud is covered with just one to two inches of loose soil. Planting the crown too deeply is a common error that can lead to crown rot, delaying or preventing successful establishment.
After placing the crown with the buds facing upward, backfill the hole and gently firm the soil to remove air pockets. Rhubarb plants require significant space to reach full size, so crowns should be spaced approximately three to four feet apart. This generous spacing prevents overcrowding, which can lead to reduced stalk thickness and overall production.
Initial Care and Waiting for Harvest
Immediately after planting, water the crown thoroughly to settle the soil and begin establishment. Throughout the first growing season, newly planted rhubarb requires consistent moisture and should be watered regularly during dry spells. Apply a layer of organic mulch, such as compost or straw, around the plant to suppress weeds and conserve moisture, but avoid burying the crown itself to prevent rot.
Rhubarb uses its first year to establish a robust, deep root system, which serves as the energy reservoir for future harvests. Therefore, the most important instruction is to resist harvesting any stalks during the entire first year. Harvesting too early depletes the energy reserves stored in the crown, compromising the plant’s long-term health.
In the second year, only a minimal harvest of a few stalks should be taken. The plant should not be fully harvested until its third year when the root system is mature. Consistent watering during dry periods and an annual top-dressing of compost or balanced fertilizer in early spring will support growth. Promptly remove any emerging flower stalks, as they divert energy away from stalk and root production.