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BEFORE YOU START Soil pH: 6.0–6.8
In-row spacing: three to four feet (3-4') (depending on variety size and vigor)
Between rows: fix to six feet (5–6')
Select a permanent location with full sun and deep, well-draining, fertile soil. Rhubarb thrives in soil that is rich in organic matter. To increase organic matter, work two to three inches of well-aged compost into the top six to eight inches (6–8") of soil before planting.
Eradicate all perennial weeds before planting.
Plant as soon as possible in the spring, after your soil has warmed to 50°F. Planting too early, in cool, damp soil, can delay development or cause roots to rot. Do not fertilize at planting or during the first season.
It is advantageous to have your Agricultural Extension Service perform a crop-specific soil test eight to ten (8-10) months before your planned planting date. Early identification of precisely what nutrients or amendments are needed, and how much, allows optimized application. Some amendments require time to take effect, and some are less effective when applied to the soil surface.
Plants require a dormant season and temperatures below 40ºF to break dormancy. Some varieties are larger and generally more vigorous and require wider spacing. Growing plants too closely together produces smaller crops and increases disease pressure.
PLANTING Set divisions in the grounds so the buds are positioned a half inch (½") below the soil surface, pointing up. You will find the buds nestled in a protective layer of dark papery husks. When planting, ensure there are no air pockets beneath the division and press the soil firmly around and over the division to eliminate any air pockets. Be careful not to break the buds. Irrigate well after planting to settle the soil and reduce transplant shock.
IRRIGATION Check soil moisture regularly and be very careful not to overwater. Maintain adequate moisture levels, especially immediately following planting. Plants should receive one to two inches of rainfall or equivalent per week, throughout the growing season. Newly transplanted plants require more frequent watering than established plants. If leaves appear wilted or limp, this is often a sign of inadequate watering.
FERTILIZATION Rhubarb needs a high amount of organic matter, so add an inch or so of well-aged compost or composted manure in the early spring. A crop-specific soil test is the best way to determine fertilizer requirements. A general recommendation is to apply one to one and a half pounds (1–1 ½ lbs) of 10-10-10 fertilizer per 100 square feet. Apply a lesser amount of 10-10-10 if you apply compost in the spring. It is best to divide the fertilizer into two to three applications during the spring and early summer, with the first application made before new growth starts. Do not fertilize after July 1, as late fertilization can generate tender new growth that will be more susceptible to winter injury. Test your pH and fertility every two to three years to maintain optimum levels.
MAINTENANCE Snap off flower stalks immediately, so plants spend all energy on foliage development. To maintain stalk size and productivity, divide plants after four to five (4–5) years. Dig when plants are dormant, in very early spring, and take care not to damage the buds while cutting or replanting. Divide the roots of the most vigorous plants into pieces about two inches (2") wide, being sure each piece has good bud development. Use these to establish your new bed. Follow the planting instructions above. Temperatures over 85°F stress rhubarb; plants may appear to go dormant during the hot summer months.
HARVESTING DO NOT EAT THE LEAVES as they are poisonous. Do not harvest rhubarb the first year. Harvest lightly (a few stalks per plant) the second year. In the third year, you may harvest stalks that are one inch in diameter for a period of six to eight weeks. As stems get shorter and thinner, stop harvesting for the season. Leave the remaining stalks to make food for the crown and next year's production.
Harvest by holding the stalk near the base and using a pulling and twisting motion to snap the stalks at the base. You may use a sharp knife to cut stalks. Cut as close to the base as possible without damaging the crown. Remove the leaf and the base of the stalk before storing. Only harvest about one-third to one-half of the stalks at a time from each plant. Though some harvesting in the fall is acceptable, rhubarb is typically harvested from early May to early June. A late-summer harvest may reduce the spring crop.
