Layering

• 1). Construct a raised bed or berm—1 to 2 feet high--or excavate the site several inches deep if a raised bed is undesirable. Either of these options will allow you to layer gravel, compost and sand to prevent access to the bulbs, according to the Virginia Tech Extension.
  
  
• 2). Cover the soil with 2 inches of sharp gravel and cover that layer with 6 inches of mature compost, which is compost that has been processed for at least 2 to 4 months.
  
  
• 3). Lay bulbs on top of the compost layer and space them three times the width of the bulb apart. For example, 2-inch bulbs should be spaced 6 inches apart.
  
  
• 4). Spray all of the bulbs with a vole repellent and allow them to dry before covering them with the next gravel layer.
  
  
• 5). Cover the dry bulbs with 2 inches of sharp gravel, then another 4 to 6 inches of compost, soil or sand. Virginia Tech recommends sand because it’s cheaper and more weed free.
  
  
• 6). Cover the bed with 6 inches of pine needles or shredded pine bark mulch for winter protection. Once leaves and shoots begin to emerge in the spring, remove some of the mulch.
  
  

General Protection

• 1). Surround each bulb with a handful of sharp, crushed gravel at planting time.
  
  
• 2). Place groups of bulbs in wire mesh baskets planted in the ground.
  
  
• 3). Spray bulbs with a pre-plant vole repellent.