It is now time to put your blocks and tubes with liners in your Mason Bee House - just the blocks and/or tubes with liners in the house for now.
There may be some mason bees out there in the wild looking for a home.
Reminder: Don’t forget to tape the back on the block. Mason Bees like to go into dark holes. If you have lost your back, you can put layers of foil tape used to seal heating vent/piping on the back of the block.
DO NOT PUT COCOONS OUT YET!
WHEN DO I PUT OUT COCOONS?
Watch the weather! Look for several days with 50-55 degree temps and no heavy rains in the forecast before putting out your cocoons. That is usually late-March- mid April. All cocoons should be out no later than April 15th.
Put out 1/2- 1/3 of your cocoons at a time. Put out a minimum of 25 cocoons each time. You should have a mix of small cocoons (males) and larger cocoons (females). If you have more than 75 cocoons you can put out 1/3 at a time.
NOTE: Do not fill the emergence tube more than half full.
While still watching the weather - Wait a week or two before putting out the next batch. We are hedging our bets on weather and looking for success.
On your trip home, keep the cocoons cool. DO NOT put by a heater vent and keep your car interior cool. IF you have a trip longer than 30 minutes, put the cocoons in a cooler or devise a way to keep them cool. Be aware that subjecting them to extreme temperature fluctuations can cause them to start to emerge before you are ready to put them outside. Cold storage helps increase survival of the bees that emerge in the spring. Even though the bees in the cocoons are dormant, they are alive, and respiring, which uses energy. The cold storage helps the dormant bees use their stored energy at a slower rate than those over-wintering at higher temperatures.
Keep the cocoons in a refrigerator (vegetable bin- a “moist zone”) at 38-39° F and 60-70% humidity to ensure the bees remain dormant. Place a dry paper towel in a container and put the cocoons on the dry paper towel. Put a smaller container with a damp paper towel (not dripping wet) in the larger container (holes in the lid). This adds extra moisture. Check the paper towel weekly and moisten as necessary. IF the cocoons develop surface mold, wash, rinse and air dry them before returning them to the refrigerator. Only use 1 tsp to 1 gallon of water for one minute. (half the strength and time used in the initial cleaning). Dry the cocoons (do not use a hair dryer) and return the cocoons to the refrigerator until you put them out.
Putting out Cocoons. Watch the 7-10 day weather forecast. You are looking for temps of 50-55° for 3 or more days in a row with no heavy rain in the forecast to decide when to put our cocoons. Put out 1/3 or 1/2 of your cocoons in late March- mid April and the rest 1-2 weeks later. All cocoons should be out by the very first week of April.
Use the OSU Extension publication “Nurturing Mason Bees in Your Backyard in Western Oregon” EM9130 (page 5 for cleaning info) for a review and information about Mason Bees.
For the Willamette Valley- check with your extension office for dates in your area.
January- June Provide water, MUD and early flowering plants. Mason Bees prefer natives.
Mid to late Feb Put out Mason Bee blocks or tubes in your houses. (not the cocoons yet).
Depending on the weather, Mason bees nesting houses, blocks and tubes can be put out in mid or late February, but by early March at the latest. A local population of Mason bees that did not emerge from your nesting system may be looking for “holes” to place their eggs.
Late March to Put 1/2 to 1/3 out your cocoons in late March and the rest 1-2 weeks later. Mid April (25 Minimum in each batch) The weather will determine when you put out the cocoons. Look for temps of 50-55° for 3 or more days in a row with no heavy rain forecast. All cocoons should be out no later than mid April. Do not fill the emergence tube more than half full. If your cocoons are in your refrigerator, where they should be they will be OK there while waiting for good bee weather. Another factor to consider- Are lots of flowers available now & for the next couple months?
October Harvest cocoons from blocks or tubes.
Registration opens in Sept. Preregistration is required due to space limitations.
October – March Store cocoons in your refrigerator. (In frost free refrigerators, add a small cup of water with a damp paper towel that acts as a wick near the cocoons to maintain humidity in the container).
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about Mason Bees and other pollinators.
 Optimum height of bee house from ground is about 3-6 feet. Yes it can be higher.
 It should be high enough to be above the splash zone, but don’t install it too high- you will want to watch the bees in action!
 The bee house should be placed on a wall that receives morning sun, such as the South-East wall of your home. If you don’t have great morning sun, give them as much as you can, bees survive in the wild without this. Your bees just do better with it!
 You also need to think where the afternoon sun is as you do not want the nesting box to be in direct sun in the afternoon, it will get too hot for the bees and may kill them.
 The opening of the bee house should face away from prevailing winds and rain as much as possible: in order to keep the holes and liners dry.
 Don’t place your house too far under a porch, as bees may not be able to find the house easily.
 Don’t place the bee house over a pond or water source. Your bees haven’t taken swimming lessons, and many could drown.
 Place the bee house away from your bird feeder, bees make tasty morsels.
 Have a water/mud supply nearby or put some clay soil with water in the area. Mason bees need mud to enclose their cocoons.
Females build and tend their own nest.
They need early blooming plants, water, MUD!
Mason bees are so-called, because they use mud in the construction of their nests, however, it is actually the common substitute name used to describe bees belonging to the genus ‘Osmia’ which are part of the family ‘megachilidae’. They are sometimes called Blue Orchard Bees.
Female Mason Bee cocoons are laid in the holes first and then the male cocoons. Female Mason Bee cocoons are 3” or deeper in the holes.
Depending on the crop 1 (0ne) Mason Bee can pollinate as much as 75-200 Honey Bees. A mix of honey bees, bumble bees, and mason bees can increase the yield and quality of a crop.
Have plants that bloom for every season to help all pollinators. Keep in mind: Hybrids may not produce much nectar or pollen. Double flowering plants don’t allow easy access to nectar or pollen. Native plants are a great choice.
Bees like white, yellow, purple and blue flowers.