When basil flowers start to drop and the flower pods turn brown, it's time to collect seeds. Only pollinated flower pods will have seeds in them so dont expect to find seeds in every pod. This is why having bees and beneficial insects in the garden is important.

Cut away the browning stems, and start unwrapping the pods to find the seeds.

It doesn't get easier than this. Now is great time to plant basil seeds, so start collecting!