RHUBARB PLANTING GUIDE

HOME GARDENER

Rhubarb is a cool season, perennial plant that is very winter hardy and resistant to drought. Its crop is produced from crowns consisting of fleshy rhizomes and buds. Following a season of growth, the rhubarb crown becomes dormant and temperatures below 40-F are required to stimulate bud break and subsequent growth.  Once planted, rhubarb plantings remain productive for 8 to 15 years. DO NOT EAT RHUBARB LEAVES, THEY ARE POISONOUS!

SITE SELECTION - Rhubarb tolerates most soils but grows best on fertile, well-drained soils that are high in organic matter. A clean planting site is essential for the cultivation of rhubarb since no herbicides are registered for use on rhubarb. 

SITE PREPARATION - Rhubarb is rather tolerant of soil acidity but does best in slightly to moderately acid soil. The crop can tolerate soil pH as low as 5.0; however, maximum yields are attained at a pH of 6.0 to 6.8.

PLANTING - Plant rhubarb roots in early spring. Space rhubarb roots 3' apart in rows and 5'- 6' between rows.  Much smaller than this will seriously crowd the plants and result in a diminished bed and increase the likelihood of spreading disease.  Plant the roots with the crown bud 2 inches below the surface of the soil. Place plants in the ground with buds pointing up. The hole for the crown should be dug extra large and composted manure or peat moss can be mixed with the soil to be placed around the roots. Give the plant 1/4 cup of 5-10-10 worked in to the top 10 inches of soil at planting time. Firm the soil around the roots but keep it loose over the buds. As the plant starts to grow, remove the flower/seed stalks as they are seen.  Seed stalks restrict the plant's growth.  Rhubarb needs cold to trigger spring growth. Rhubarb tolerates very cold (-20 F) very well.  

FERTILIZER, IRRIGATION & WEED CONTROL - Rhubarb responds well to fertilizers. The quality of the crop harvested depends to a large extent on the care and fertilization received.  Home gardeners should give each plant 1 cup of 10-10-10 fertilizer each spring, applied in a circle around the plant when growth starts. Fertilize each year and cultivate shallowly as often as necessary to remove weeds. Water the crowns after planting and maintain good moisture throughout the establishment period. Good garden drainage is essential in growing rhubarb. For home gardeners, planting in raised beds helps ensure against rotting of the crowns. Small areas of perennial weeds can quickly build up to serious proportions. To prevent this, all perennial weeds should be killed the year before planting. The bed should be cultivated (hoeing) in the spring and after cutting. Rhubarb is relatively free of insect and disease problems.

HARVESTING -   Refrain from harvesting rhubarb the first year. Each plant needs time to build up food reserves in the root to produce thick, robust stems.  See the Chart below for harvesting times:

When harvesting rhubarb, the first step is to cut the stalks at the soil line or simply pull them out individually. All of the stalks (1 inch and larger in diameter) of a plant may be harvested over a 6-8 week period. After the stalks are cut, the leaves may be removed. Some Fall harvesting is acceptable.  Rhubarb hit by a frost or freeze can still be eaten provided the stalks are still firm and upright. If the stems appear soft and mushy, do not eat them. If in doubt about the safety of eating the stalks, don't. Cut those stalks off and discard them. Allow new stalks to develop before eating.


DIG and DIVIDE - It is normal to reset a bed after 4-5 years.  Established clumps will have to be trimmed every 4 to 5 years or when the stalks get small and spindly or when the crown is visibly crowded. This will help the plant to keep growing nice thick stems. This is done by digging around and trimming the crown down to 4 or 5 buds. You can also use this opportunity to divide your plant into more plants. You may encounter rot in the crowns from excessive water in the crown area. If so, destroy these plants.