Harvesting Rhubarb

Rhubarb is a common perennial crop grown for it’s large, thick leafstalks. One of the most common reasons for a lack of success growing rhubarb is harvesting too much or harvesting for too long of a time. Since rhubarb is a perennial crop it draws on the food reserves stored the year before for vigor and strength to leaf out and grow in the spring. An established planting of rhubarb can be harvested for approximately 8 weeks and begins as soon as the stalks are large enough to use. Harvest only the largest and best stalks. They should break off easily if pulled slightly to one side.

After harvest season, be sure to leave the stalks that develop to grow so the plant can store food for the next season. Following harvest, it’s also important to fertilize the rhubarb with a fertilizer containing mostly nitrogen such as nitrate of soda. Other high nitrogen fertilizers can be used, just follow the directions on the label. A fertilizer application should have been made in the spring as the plants start to leaf out. If the rhubarb starts to make a seed stalk be sure to remove it so the plant puts more energy into food reserves.

Summer is the wrong time to rejuvenate a rhubarb bed however rhubarb should be rejuvenated every 5 to 10 years or if productivity has been decreasing over the last few years it is time to consider rejuvenating the bed in the early spring. You can dig up and divide the crowns in the sections and then replant. Remember not to harvest the first year after rejuvenating.

Have questions? Contact our office where our Horticulture Extension Agent will assist you with questions.

Phone: (316) 321-9660

Email: callae@ksu.edu