Build a nesting block for bees.

Time: 
Morning

Honeybees are crucial to producing about one-third of all the food we eat. The list of crops that simply won’t grow without honeybees is a long one: apples, cucumbers, broccoli, onions, pumpkins, carrots, avocados, almonds…and it goes on. (Download NRDC's Bee Facts for a full list). Without bees to pollinate many of our favorite fruits and vegetables, the United States could lose $15 billion worth of crops. Are we speaking hypothetically? Well, no. Researchers estimate that one-third of all honeybee colonies in the United States have already disappeared.

One of the biggest challenges bees face is finding suitable nesting sites. The majority of our roughly 4,000 species of native bees (honeybees are a European import) are solitary—essentially, single mothers raising their young alone. Having no hive to defend, they’re not aggressive and rarely sting.

About 70 percent of native bees are ground nesters. A small patch of bare earth—as little as 1 square foot—in a sunny spot is all they need. The remainder are mostly wood nesters: they will occupy holes in trees bored by beetles or will move into nesting blocks like the one shown here. Female bees will lay their eggs in the holes, then seal them; their offspring will emerge the following spring to carry on.

Recruit your kids to help you make a nesting block to put in your garden or yard. It’s easy. The Xerces Society offers these simple instructions:

  1. Start with a piece of wood at least 4 inches thick and 8 inches long. Use untreated lumber and avoid cedar, which is toxic to insects.
  2. Drill a grid of holes varying from 3/32 inch to 3/8 inch in diameter, spacing them approximately ¾ inch apart. Drill deep holes, even going all the way through the block, to maximize the nesting depth.
  3. Attach the block to a backing board and install a sloping roof that extends in front of the block to shelter the holes from the elements. Mount the backing board on a sturdy fence, post, tree or building in a site where the holes will get only gentle morning sun.
  4. As an alternative, prepare nesting tubes: Any hollow plant canes, reeds or stems with an internal diameter of 2 millimeters to 1 centimeter can be used for this purpose. Even cut bramble and rose stems have pith into which tiny bees can burrow. Cut canes and stems into sections 10 to 20 cm long. If using bamboo canes, be aware that they have sealed nodes, and cut them so that long hollow sections are exposed. 
  5. Bundle the tubes with garden twine, string or wire.
  6. Hang them up. Place and anchor your nest on a sunny or partly sunny shelf in a shed, or improvise a similar situation. Make sure the nest is protected from the rain.