Farming Madder

I just received info that you may be able to supply me with madder, Rubia tinctorium. This is traditionally used in painting, specifically the root, as the colouring matter or pigment of rose and red lakes (transparent glazing colours). I use the product now, as it is produced by Windsor and Newton (already processed, and ground in oil paint). Though they offer only a single product, and I am aware that much can be done with the colour of madder according to how it is processed.
Could you please supply me with whatever info you have the time for: ordering, growing, etc.? I would like to 'farm' it myself for the above purpose.

There is not much known about madder as a commercial crop. It is a perennial, rated hardy to zones 5 to 10, and it is very easy to grow. We found that it competes well against weeds on our farm which is in zone 5 with sandy soil. There are 42-44 seeds per gram and typical germination percentages are 50-75%. It grows 25-100 cm high and spreads 25-100 cm wide. In several years of growing it in rows we have not noticed any pest or disease problems.
Because the seeds are a little slow to germinate, taking 11-22 days to germinate, we recommend sowing in plug trays and then transplanting the plugs to the field.
What the economics of the crop is we have no idea. We have no yield information available.