Rhodiola Rosea Culture

I have some questions with respect to the Rhodiola rosea which I grew from your seeds(S5040). How old does the plant have to be before the roots are harvested ? I harvested one 2-year old plant and found the roots to be quite small and white. "The Rhodiola Revolution" by Brown and Gerbarg, describes the roots and the tea from them as *red* ?

The plant has to be a multi-stemmed plant before it is big enough to harvest. The time taken to reach this varies greatly depending on how well the plant likes the conditions provided.
According to experiments done in Russia, it will grow fastest at intensive under light culture, reaching harvestable size in 245 days. This is 1.5 to 3 times faster than for plants grown expertly in a field. The greatest increase in rhizome weight occurred about half-way through the growth period that is from days 137 to 245 in the under light trials.
My guess is that under your conditions you would have to let the plants get to four years of age before harvesting.
According to my reading there are two strains of this plant, one with white roots and one with yellow roots. My guess would be that the yellow roots produce the red tinted tea.