The roots of madder are used to make reds that can then be altered by changing temperature or ph. The end result also depends on the age of the root. For deeper reds, harvest the roots when they are at least three years old. Dry the roots for a deeper red. Fresh roots provide a more orange-red. Madder can spread in the garden, so keep it contained. Plant in full sun and free-draining soil. Better reds are obtained with calcium-rich soil, so add lime during autumn or winter.