Mason Bee Keeping


Thanks everyone!
@zendog. Yes, placement is important but so is timing. I’m placing it under the eave of a shed so it should be in the shade from about noon on, and it is white, which I can also cover with a piece of aluminet. Since it is put out early - when fruit trees are blooming, warmth is an asset initially. Probably good to monitor this, though. I have a thermometer which telemeters data to the house so I can watch all this. I’m more concerned about freezing them than baking them. :blush:

The nesting blocks will be removed from the ‘bucket house’ about 6 weeks after the last release of the bees (if you are staggering releases). In my zone this should be before our days become uber hot - I’m estimating late May/early June. I’ll place them in fine netting in a smaller bucket in the garage such that the wasp predators can’t get access to them. My main concern here is our humidity and the fungal issues that that can favor, so I may bring them in the house.

I would like to get some of them out early enough for pollinating, and, if need be, bring the bucket in at night if we get a late arctic dip. I’m also considering some type of heater, but haven’t thought that through enough. I noticed early in the thread folks were concerned about cold getting their mason bees with weather shifts. So that is where I may need more thought and a plan.


Bringing the bees in early in June avoids most problems with predators.

The mono wasps will be in the cocoons with the bees, but they hatch later, to parasitize the larvae/pupae. Once the bees have hatched in the spring, get rid of all the unhatched cocoons and make the bees use clean new houses or tubes. They won’t want to do this, pheromones call them to their old nests, but too much disease and pests there.

Most springs in a cold snap I worry about the bees freezing or starving because they hatched when no food was available. Amazingly, they seem to survive anywayhow


This might bee useful. :blush:


I do not see much discussion on leaf cutter bees, are they just not practical to raise for pollination purposes?


I believe they are, but my understanding is that the masons come out earlier. Here, I seem to have abundant pollinators when it is warmer, but wind up taking a paintbrush to my plums, et al because cold weather pollinators are not around.
The leave cutters kinda tear up some foliage, if that matters to you. :blush:


i put out both.


bumbles are out on 50 deg. days here and continue even after some frosts.


I had both mason bees and leaf cutter bees in my mason bee tubes when I opened them this fall. The leaf cutter were from the wild.
I let my bees stay out until after freeze up. I wash my mason cocoons and them put them in a small styro container with a pad of moist towel and place them in my fridge. The leaf cutter are supposed to stay warmer.


How does one wash a mason bee cocoon?? Soap and water and very carefully? Or is there anything else to it? Reminds me of a song my parents used to always sing, called Bringing Home a Baby Bumble Bee. Ever heard it?


you put them in warm water and swirl them. They are very resilient you can rub them gently between your fingers to get the crud off. Here is a picture of them floating, if they sink they usually are dead,have a hole, or a wasp larvae inside.

The following directions are from Mason Bee Central web page.

Place the loose cocoons in a cool bucket of water and swirl them around for several minutes, this will separate most of the mud and many mites. Remove the cocoons, dump the water and repeat with clean water. Do this until the water stays fairly clean. Now prepare a 5% unscented bleach solution and swirl the cocoons around in itfor 5 minutes. Rinse with fresh cool water, let them dry on a paper towel at room temperature and you are finished.


Crown bees has many videos on various aspects of mason bee keeping. The videos are on their website and also on YouTube.


Too much moisture in storage can cause the cocoons to mold - this is survivable, but really ugly


So buy some tiny towels and make sure they get a chance to dry their britches before going back to bed…


I put a little bit of paper towel in a small plastic cup and just keep it slightly damp. The cocoons are in another lidded plastic cup with holes punched in the top. They don’t seem to mould or dry out.


i just took out my 40 or so reeds full of cocoons i had put in my unheated garage on a shelf. every single one had a exit hole in it and as i split the reeds the cocoons were all dust! is it possible for them to hatch early!? there aren’t any pests that i know of in there and the pail was high on a shelf. it looks as if they hatched. never had this happen before. i counted all the cells in these reeds. had they survived i would have had about 200 cocoons! guess ill have to buy some more now.


Sounds like something got them. I don’t think they ‘hatched’. I’m curious what size the ‘exit hole’ was. Could actually be an entrance hole of whatever got to them. :frowning_face:


If the exit hole is small, it was likely mono wasps. They consume the bee larva inside the cocoon, then leave via a small hole as adult wasps


they were fairly small holes. but wasps in all of them? not even 1 viable cocoon in almost 200. at least they probably died in the garage.


I’m thinking that if you had an infestation of mono, that they were able to overwinter last year. So I wouldn’t count on their being dead, and take precautions for next year.

I mean look how many are on this mono trap.
Do I understand correctly that you saw none of this last year?


On some of crown bees videos, they show and explain that reeds of different sizes are much more attractive to mason bees than blocks. I have also found this to be true. Your diagram looks like you drill holes in a block.
John S