How to Sow Annuals
The big advantage of growing brightly colored annuals is that you can try out new fun ideas and combinations each year. They are easily raised in spring, and keep impatient gardeners busy before the rest of the garden takes off.
From: DK Books - Containers for Patios
Step 1: Prepare Pots
Fill new or clean pots with seed-starting mix, adding some horticultural or sharp sand to improve drainage, and give them a quick tap to settle the mix. Make sure that there is a gap below the pot rim to allow for watering.
Step 2: Water the Soil
Water the soil with warm water using an upturned spray. Hardy annuals can be left outside once sown, but half-hardy annuals need a warm, bright windowsill indoors, away from direct sunlight.
Step 3: Plant the Seeds
Take a few seeds, and space them out on the soil. Cover them with sifted potting mix to the depth given on the seed packet. Really tiny seed is best mixed with fine sand before it is scattered over the soil.
Step 4: Label Pots
Clearly label each pot with the name of the seeds and the sowing date. This is particularly important when you do all your sowing on the same day. Place pots on a windowsill or in a greenhouse to germinate.
Many small seeds need light to germinate. Perlite allows in light, and keeps them moist.