Prepare to plant the bulbs in the fall. After the summer weather has faded into fall, and the nights have gotten colder, it's time to plant your bulbs and start dreaming of spring again. You want to plant the bulbs before the first deep frost, which hardens the grounds and makes it much more difficult to dig holes for the bulbs. The bulbs should be planted when the soil is still at least 60 °F (16 °C).[1]