Rhubarb is a hardy perennial vegetable, typically used as a fruit for its tart, edible stalks. This long-lived plant is a favorite in temperate climates, providing one of the first fresh harvests of the spring season. Achieving a robust rhubarb patch depends on proper planting during specific seasonal windows to ensure successful root establishment. Knowing when to plant is the first step toward a bountiful, low-maintenance harvest.
Optimal Timing for Planting Crowns
Planting rhubarb via crowns—pieces of the root system with at least one bud or “eye”—is the most recommended method for home gardeners. This technique bypasses the slow start of seeds and ensures the new plant is genetically identical to the parent stock. Crowns must be dormant during planting to prevent shock and encourage healthy root growth before active foliage production begins.
The primary window for planting dormant crowns is in the early spring, immediately after the ground is workable and before new growth starts. Planting at this time allows the root system to establish itself in the cool, moist soil before summer heat arrives. A soil temperature of at least 50°F indicates suitable conditions.
A viable alternative is late fall planting, which should occur after the foliage has died back and full dormancy has set in, typically four to six weeks before the ground freezes solid. Fall planting allows the crown time to develop root structure throughout the winter for an earlier emergence the following spring. When planting, set the crown with the bud facing up, covered with only one to two inches of soil to prevent rot.
Timing for Starting Rhubarb from Seeds
While crowns are preferred, growing rhubarb from seed is a cost-effective alternative that requires more patience. The primary drawback is genetic variability, meaning resulting plants may lack the desirable color, flavor, or vigor of the parent variety. Furthermore, the time to a full harvest is significantly longer compared to planting crowns.
To grow from seed, start them indoors approximately eight to ten weeks before the average date of your last expected spring frost. Starting them early provides the young seedlings with the necessary head start to establish a strong root system. Once the seedlings are about four inches tall and the danger of hard frost has passed, they can be transplanted outdoors.
If you choose to direct sow, do this in the spring as soon as the soil is warm enough to work, though this results in slower establishment. Seeds planted directly into the garden will require careful thinning to select the strongest performers. The initial year of growth from a seedling is entirely focused on root development.
Preparing the Planting Site
Rhubarb is a permanent addition to the garden, often producing for 10 years or more, so site preparation is important. The site must be in full sun to partial shade, receiving at least six hours of direct sunlight for optimal stalk production. Excellent soil drainage is required, as the crowns are susceptible to rot in waterlogged conditions.
The soil should be loosened deeply, ideally one to two feet, to accommodate the extensive root system. Incorporate a significant amount of organic matter, such as well-aged compost or manure, into the planting area. Rhubarb is a heavy feeder, and this amendment provides the necessary nutrients for long-term productivity.
Rhubarb grows best in slightly acidic to neutral soil, with a pH range between 6.0 and 6.8. If your soil is heavy clay, consider planting in a raised bed amended with coarse materials to ensure water moves away from the crowns. Removing all perennial weeds from the area before planting is also important, as they compete with the young plant for resources.
Initial Care and First Harvest
After planting, initial care focuses entirely on establishing a robust root system. Consistent moisture is necessary during the first year, particularly during dry spells, so water the plants regularly and deeply without allowing the soil to become waterlogged. Applying a two- to three-inch layer of organic mulch, like straw or shredded leaves, around the plant helps conserve soil moisture and suppress weeds.
Rhubarb may produce a flower stalk, or “bolt,” which should be removed immediately by cutting or snapping it off at the base. Allowing the plant to flower diverts energy away from the roots and stalk production, weakening the crown. Removing these stalks ensures the plant’s resources are focused on vegetative growth.
The most important rule is to avoid harvesting any stalks during the first year of growth. This allows the newly planted crown to dedicate all its energy to root establishment, which is necessary for long-term health and future yields. In the second year, you may take a very light harvest of just a few stalks if the plant appears vigorous, but a full, sustained harvest should only begin in the third year.