The required planting depth is based on the size of the bulb. The general recommendation for bulb planting is to dig a hole that is 3 times the height of the bulb.
It has a ruler that measures and shows the exact measurements. It is able to create a hole and then fill it up after planting. When you squeeze the sides, it releases the soil into a pile beside the hole.
To plant these bulbs, dig a small hole and loosen the soil at the base. You can dig an extra 2-3 inches to loosen up the soil. This will help with root growth.
If you plant your bulbs too shallow, they risk being discovered by squirrels or chipmunks. They could also be vulnerable to dramatic changes in the weather that causes sudden thawing and freezing.