Select and prepare a bed for the thrift seeds six to eight weeks before the first expected frost of autumn. Choose a sunny bed with good drainage away from overhanging shrubbery or dense vegetation.
Break up the soil in the chosen bed using a rotary tiller or a handheld soil cultivator. Loosen and work the soil to a depth of at least 6 inches. Remove stones, sticks or other debris present in the bed.
Smooth out the surface of the soil. Sprinkle small pinches of thrift seed across the surface of the bed as evenly as possible. Do not cover the seeds, as light aids germination.
Water the bed thoroughly after sowing the thrift seeds. Use a garden hose with an adjustable nozzle set to "shower" when watering the bed. Wet the soil to a depth of 3 inches. Maintain moisture at that depth during germination.
Watch for signs of sprouting in two weeks. Thin the thrift seedlings to one every 6 inches as soon as they grow to 2 inches in height.
Spread a 1-inch-thick layer of straw between the thrift plants to protect the roots during the autumn and winter. Remove the straw in spring when soil temperatures reach 55 degrees Fahrenheit.