Place the seeds in a re-sealable plastic bag with a couple of moist paper towels when outside temperatures stay above 55 degrees Fahrenheit at night. Seal the bag and place the seeds in the refrigerator for seven days. Lupine seeds seem to germinate better after cold treatment.
Scratch through the coating with a nail file on one side of the seed and place in warm water to soak for three hours. Check the seeds in the water. The lupine seeds that sink to the bottom are ready to plant. Fish out the floating seeds and scratch them again. Soak the floaters in warm water again until they sink.
Dig the soil to a depth of 12 to 20 inches with a shovel in an area with full sun or light shade. Lupines grow best in dry sandy or gravelly soil but do not survive constantly damp and heavy soil. Break the soil up with the edge of the shovel and rake smooth. The deep soil supports the long taproot that lupine flowers develop which anchors the long flower spike and lets the plant survive drought conditions.
Lay the seeds on top of the soil, spacing the seeds 12 inches apart. Cover the seeds with 1/8 inch of soil and sprinkle water over the planting area. Keep the soil moist throughout the germination process. It takes 15 to 75 days for lupine sprouts to appear when the soil is 55 to 70 degrees Fahrenheit.