imp: I think there is too much of a big deal made over soil. These plants are literally weeds, they will grow through cracks in tarmac if you let them. I have always used bog standard seedling compost to start my plants off and it has worked fine every time. The only thing I would suggest is not to use soil from the garden as it will have hundreds of insect eggs and bugs in it, which will end up living off your plants. BTW - I live in England and I haven't had a good session for ages!