Purple Basil Growing Too Slowly

I am a greenhouse grower (13,000 sq ft). One of the crops that I produce is basil. I have made several attempts to produce a purple basil which is used by some of the more up-scale restaurants as a garnish. The problem that I have is that the purple varieties that I have tried grow very slowly. Is there a more vigorous variety?

Purple varieties grow a little slower than similar green varieties, but we have not noticed a large difference. Among the purple leaf varieties we carry – Purple Bush, Dark Opal, Rubin and Purple Ruffles – the last two are your best choices. Dark Opal has deteriorated as a variety over the past decade and is no longer completely purple. The Purple Bush variety is a small-leaf variety which is not suited for your market.
In general, we have noticed that variegated and purple strains of herbs tend to grow more slowly than similar green varieties. We assume that purple and variegated varieties do not have as much chlorophyll, the green pigment in leaves needed for photosynthesis. We have not seen any studies to support this theory, but it may help explain the slower growth of purple basils.