SeeDs to sow now
It's all in the timing. Late Summer is perfect for sowing hardy annuals. You're aiming to get good, solid, happy little plants by the time the days shorten and the weather chills. If you sow too late, they don't get the growing in that they need to before the winter. Too early and you'll have a panicked plant pumping out flowers in order to set seed this autumn.
Lots of seeds like direct sowing (putting them straight into the soil outside) so don't be afraid to treat them a bit mean. I'm doing a mix of direct sowing and into trays this year because my field will be full of blooms for cutting right up until the first frosts. If this drought carries on, just make sure you keep them moist until they've germinated and got a good root system established.