Most of us are soon heading out to buy our annuals to plant when all danger of frost is past in our area. Some of us may have already started our seeds indoors. I do not start any seeds indoors, but there are some seeds that I direct sow onto my garden once the soil has warmed up.
I just can't resist buying seed packets when I see them, mainly some leaf lettuce and New Zealand spinach that I grow in pots on my deck in the hope of outwitting the rabbits. I also rake or rough-up the soil in some of my flowerbeds once the ground is warm enough and scatter the seeds of annuals such as celosia, cleome, zinnias, and marigolds, as they are so easy. I just scatter them in what I think will be the bare spots in my perennial beds, and then I throw a little potting soil over the area to camouflage them so that the birds don't gobble them up.
Cosmos seeds are easy using that method too, and I look for the shorter varieties of those.
Sweet alyssum, a low-growing edger, also grows easily from seed, as does the lovely blue clary sage. It will bloom happily from June until frost. I don't bother to pull up the seedlings to thin them when they appear. I just cut them to the ground with nail scissors.
There are usually enough spring showers to keep the plants growing and many may even self-sow next year.