well, i displayed a couple of flyers around town tho' i know it'd draw more attention if they were displayed in out of town garden centres but as i don't drive, it would have to be those who go into libraries and s/markets to draw the pubic in (tho' one is at a busy plant stall in the indoor market).
winecap: i'm not part of the City Farm, I just know someone who's part of the gardening team and I've volunteered my time this Sunday (they're always crying out for volunteers as their funding is limited yr upon yr). I think last year were their first year in hosting the event, but they had their tables set out with under different headings - veg (these are sub-divided), flower, annual, perennial etc., They also had a corner for children to take part in an art activity with seeds with glue - lentils, pulses of various colours etc.,