Hi Venus ash trap,
You live in the UK?
You won't need extra lighting, you can get a cold frame from somewhere like B&Q Do-it-all etc and your Purps,VFTS will do well in full light in your garden. Even better is they will get the required dormancy outside. Please look at my website at the link below. All my Sarras go through the winter unheated. You can get a cold frame for around £30 and costs nothing to run!