Outcast Cardamine Ship

[Python 72]

Outcasts rely on cardamine to survive, it is their blood etc and when they travel too far away without having any, they suffer disease death and all other manner of dastardly things. Currently the only source of Cardamine available is that on Malta, from where the entire Sirius wide supply is drawn from.

Since the Outcasts have no other viable planets under their control, I was wondering whether they could grow cardamine in biodomes, which would allow them to construct colony ships like the jinkisu, though probably on a smaller scale. These colony ships as I will call them would allow easy long term expansion into more hostile parts of space, without reliance on links back to the Outcast homeland. This ship could provide another RP extension for Outcast players other than the militaristic avenue.

So is there any lore reason why this isn't possible? can cardamine not grow anywhere else, have they not tried? can they not get hold of biodomes? Any ideas?