Place the seeds in a resealable plastic bag with a couple of moist paper towels when outside temperatures stay above 55 F (15 °C) 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 (30-50 cm) with a shovel in an area with full sun or light shade.
- Lay the seeds on top of the soil, spacing the seeds 12 inches (30 cm) apart. Cover the seeds with 1/8 inch (1 cm) 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 55-70 F (15-20 °C).