How to Grow Rhubarb
Do not fertilize close to planting time or during the first season. Plant in the early spring, in well-prepared, weed-free soil. To increase organic matter, work two to three inches of well-aged compost into the top six to eight inches of soil prior to planting. Good drainage is absolutely necessary. If you have heavy or slowly draining soil, you must plant rhubarb in raised beds. Set divisions in the grounds so the buds are positioned ½ inch below the soil surface, pointing up. You will find the buds nestled in a protective layer of dark papery husks. When planting, be sure there are no air pockets beneath the division, and press the soil firmly around and over the division to eliminate air pockets. Be careful not to break the buds.
Fertilizer requirements are best determined by a soil test, but a general recommendation is to add an inch or so of well-aged compost by early each spring or 1–1 ½ pounds of 10-10-10 fertilizer per 100 square feet. It would be best to divide that amount of fertilizer into two to three applications during the spring and summer with the first application before new growth starts. Do not fertilize after July 1, as late fertilization generates tender new growth which will be more susceptible to winter injury. Check your pH and fertility every two to three years.
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 large 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 lead and the base of the stalk before storing. DO NOT EAT THE LEAVES as they are poisonous. Only harvest about 1/3 to ½ of the stalks at one time from each plant. Though some harvesting in the fall is acceptable, rhubarb is typically harvested from early May to early June.