I'm going to be growing courgettes from seed and I'll be starting them off in pots in a greenhouse. Will sieved soil from my garden be good enough? I know it needs to be low-nutrient.
Also I've got an e-book about the science behind growing plants if anyone's interested, it's pretty accessible.
http://www.mediafire.com/view/ro8oozlz68gciiq/Botany_for_Gardeners_by_Brian_Capon_%28Timber_Press,_2004%29.pdf