Work the soil 6 inches deep, breaking up all clumps at the planting site using your garden spade. Add just enough compost or peat moss to aerate the soil if your soil is heavy clay; Sweet Alyssum does not require additional fertilizer.
Rake the area to level the ground after using the spade. Water the area lightly with your garden hose, just enough to soak the soil 3 to 6 inches deep.
Spread seeds by hand and then cover with a thin layer of soil--use just enough soil to prevent the seeds from blowing away.
Thin the seedlings by hand to at least 6 inches apart when they are 4 inches tall.
Manage sprawling plants, as well as plants that have spent blooms, by clipping them back with garden shears. This will not harm the plants and they should easily come back and bloom again.
Water your Sweet Alyssum only when the top inch or two of soil has dried. Over watering these plants can lead to rot.