Prepare a soil bed for spring planting of your yarrow lawn. After the last hard frost, till the soil up to a depth of at least 6 inches. Remove all roots, weeds, rocks, soil clumps, other plants and any other debris from the soil. Rake the soil surface until it is level and relatively smooth.
Mix 1/2 lb. of common yarrow seed with 1/2 lb. of clean sand for every 1,000 square feet of planting soil. Combine the two in a bucket, churning gently with your hands to combine evenly.
Hand-cast the sand and seed mixture evenly over the surface of the soil.
Nestle the seeds into the soil surface by walking with a weighted lawn roller over the entire seeded area. You want the seeds in direct contact with the soil but not buried deeply in the soil.
Water lightly with a fine mist to wet the soil surface or hold off if rain is anticipated in the coming days.