Learn how you can plant and care for rhubarb with this gardening tutorial. As rhubarb is likely to be in one position for many years, ground preparation is very important. Plenty of organic matter in the form of garden compost or rotted manure should be worked into the soil and base of planting hole.It's also time to cover any clumps of rhubarb outside that you want to force into early growth. The idea is to exclude light from the new shoots which forces them to grow tall and light pink in color. Depending on the weather, it will be around 6-8 weeks until we can harvest.