Sow now for a riot of colour in June?
I am holding a large garden party on 15th June and would like my garden to be a riot of colour! I have bought a lot of packets of annual seeds - cosmos, petunia, busy lizzie, marigolds etc, but many of them state to sow March - April for flowers in July. I have tried sowing some cosmos on a windowsill in the hope of getting them to flower earlier, but they have come up really leggy and I don't hold out much hope for them. I have a greenhouse but it is unheated. Am I wasting my time sowing earlier? Are there any seeds I can sow now for flowers in June?