How to Help the Mason Bees

Many people don’t yet know about the industrious little mason bee, although his popularity has grown a lot since our honey bee has been facing issues. The Mason bee is much smaller than the honey bee but it pollinates about 75% more efficiently. Visually, it looks more like a common housefly but it definitely isn’t, so try to look and make sure it’s actually a fly before you swat.

It’s important that we help the Mason bees and provide habitats for them whenever possible.Mason Bee 

Most everyone knows about the honey bee and how critically important its pollination duties are to the food supply we rely on.

It’s also been well publicized that our honey bee is in serious trouble due to viruses and wide spread pesticide use. They’re dying off at an alarming rate. This is why we need to help the Mason bee survive and thrive at every opportunity.

If we all take small scale action in our own backyards, we can make a real difference.

About the Mason Bee

There are over 300 different species of them in the Northern Hemisphere. Due to their size and docile nature they often go unnoticed or mistaken for flies. 

They’re always in the garden finding natural places to live, but with our help the bees will do much better and we can play a big part in helping them increase their population numbers. If you hang up a mason bee house customized just for them then you’ll give these important little creatures the boost they need to thrive and reproduce every year. 

The reward for you and your plants is, of course, that your garden gets well pollinated. You’ll have many beautiful flowers and a bountiful harvest of fruit and vegetables with these little guys helping out.

Mason bee barnSupplies 

The price options and design options are numerous when buying a commercially made bee homes. 

You can also make one of your own out of a few small chunks of wood nailed together and paper tubes. There are basic construction plans available online, but it doesn’t need to be much more than a small square frame.

One option is to buy a package of natural small bamboo sticks (not the coloured ones), they are usually very cheap. These are actually tubes that when you cut them to 6″ lengths they become perfect for the bees. See the image below for an example.

If you prefer you can purchase specially made paper tubes each year for them to lay their eggs in. Replacing them annually is required to keep them healthy and disease free. 

This image shows a Mason bee and bug house together which serves dual purpose of creating a home for the bees and other beneficial insects as well such as Ladybugs.

Bee house protectionMason Bee and Bug House done with twigs and cut bamboo stakes

Whether you buy a commercial mason bee house or make one yourself it’s very important to put a large piece of wire mesh in a dome type shape over the entire house. Secure the mesh to the tree or fence completely with a stapler so that there are no gaps for birds or mice to get in.

Woodpeckers love to eat mason bee cocoons and will happily sit on the edge of the house and peck out your little bee nursery in no time at all. Applying the mesh correctly and completely will stop the birds’ access in their tracks.

The mesh should have small 1/4″ square openings. This is to allow the bees to come and go freely but no larger predators can get at them.

How to hang the house

Hang the house filled with the empty tubes about 4′ off the ground on a tree or the side of your house in the early spring. Choose the side of your house that gets the warmest at the earliest point in the day. 

Once you hang the house, you likely won’t need to buy cocoons because the bees that are already around will begin to use these tubes on their own to lay eggs for the next year.

To increase the Mason Bee population in your area you can buy additional packages of cocoons in the early spring containing new bees that are dormant. 

Replacement Mason bee tubesWater

Mason bees and all beneficial insects need water too. It helps them stay hydrated and able to fly the long distances required to find flowers. However, mason bees also drown easily. Sitting a bird bath in the garden may seem like a good solution but it’s actually very dangerous for the little bees. 

The best way to offer water to your mason bees is to set out a glass dish or pie plate filled with glass marbles. Then fill the dish with clean water. The bees can stand on the marbles and take a drink of water safely. Wash out the dish and marbles often so the water stays crystal clean without garden debris or bird poop.

If you ever see a honey bee or bumble bee just sitting on the ground or on a plant not moving…but you can tell that it’s alive, it’s very possible that the bee is thirsty or tired. If you offer him some water he’ll likely take it, recover and then fly away.

Life Cycle

The mason bee is a solitary bee and does not live in a hive. It doesn’t make wax or honey either and they are very docile.

The males cannot sting at all and the females will only sting if they are threatened. This makes the mason bee quite safe to be around and to have in the garden doing their job, right along side the kids and family.

  • The females do most of the work 
  • The males die after mating in the very early spring
  • They don’t carve out their own places to lay eggs
  • They use holes bored by other creatures that have since been abandoned, this is why they are so quickly attracted to the paper tubes we put out for them.
  • The female spends the summer pollinating, collecting food and laying eggs
  • The eggs that are destined to be female get laid first and the male eggs second toward the front of the tube
  • Then she packs the tube with mud between the two cocoons and on the outside as well, that’s how it stays for the winter
  • The males emerge first in spring and hang around close to the house until the females emerge
  • They mate right away and then the males die

The female carries on with the work of pollinating and laying next years eggs. Then the cycle repeats again. 

Wire Mesh to Protect Mason Bee TubesMason Bee Protection

The 1/4″ wire mesh is required to keep out birds and other creatures that love to eat mason bee larvae.

Once the spring mating and egg laying season is over there is no traffic to and from the nest. Most of the tubes should be mudded over by now. This happens by about May and then the female adults die by the end of June.

Now, the little mason bee nursery needs another layer of protection.

It’s at this time that they face the Parasitic Wasp, whom also love to eat the mason bee babies. They can fly right through and past the wire mesh to eat the babies.

Organza Fabric Bag for Mason Bee ProtectionMason Bee Protection BagSo, at this time it’s important to take down the wire mesh and apply a fine fabric mesh to the bee house. The options are to buy a commercially made bag like the one to the left or make one yourself using raw organza fabric such as the one to the right.

Leave this fabric on for the summer months so the babies are protected until they mature. Once the summer is gone and the winter arrives, it’s time to take down the house and put it in the garage for the winter. Before winter storage it’s important to remove any dead tubes or those that look sick.

Store the cocoons at 32°F – 41°F (0°C-5°C). If you don’t have a garage or if it generally remains too warm then store them in the refrigerator. 

I encourage you to help the mason bee by setting up a home for them in your garden.

Leave me a comment, let me know if you need additional guidance and also tell me about your experiences with Mason Bees if you already have them.


17 thoughts on “How to Help the Mason Bees”
  1. Woodpeckers are the worst! After the mason bees had filled every tube in their second year, the woodpecker came and ate all of them before I realized what that “tapping” sound was…. Now I will protect them with a hardware cloth as recommended. It just happens suddenly when the woodpecker finds the nest. My mason bees were on the west side of my house and protected with a overhang roof. Sooo sad!! Don’t let it happen to you.

    1. Hi Jasmine

      That’s terrible, so sad to lose those babies…the birds love them just as much as we do! Thank you for your comment and helpful assistance to other readers.

  2. I received a Mason bee nesting box for Mother’s Day and looking at the mesh bag you recommend, I’m wondering how they get in and out of the box if you use it? I’m new at this and have several bird feeders in my garden. How far away does the nesting box need to be from a feeder? Thank you for your help.

    1. Happy Mother’s Day, what a very cool present to get! The fine mesh bag is only for after the bees have laid and sealed their eggs in the tubes before the winter. It’s to protect the cocoons from hungry birds and other predators after the adult bees have died.

      During the summer while the bees are active the best way to protect the nesting box is to put a cover of wire mesh over it, small wire mesh like 1/4″ squares. This will allow the bees easy access but stop the birds from getting close to the tubes. There are many ways to do this based on the design of your bee home and the types of surfaces you’re working with, but generally put the mesh completely over the house and secure it completely but leave a little space in front so that birds with longer beaks can’t get close to the tubes either.

      I’d put the nesting box a fair bit away from the bird feeders, you don’t want your bees to be unnecessarily easy food for the birds.

      The best place for the mason bee house is 6ish feet of the ground, under an overhang of your house on a sheltered sunny wall. The height will help protect them from ground predators and the sheltered sunny spot will provide them with warmth early in the day so they can warm up and fly. Their bodies do not regulate or hold their own heat and they need to be 90 degrees F in order to fly. Let me know how it goes and if you have more questions.

  3. Hi there,
    I have these tiny flies all surrounding my mason bee house. They are small but not as small as a fruit fly. They are black and have a red head. I wish I could leave a picture.
    Any ideas?

    1. Hi Lisa,

      My initial research on this suggests they are Fungus Gnats or parasitic wasps. Have you seen any of the cocoons with a tiny hole in the side?
      I’ll get back to you as soon as I can find a reasonable solution to it.

      1. Hi Lisa
        I think I’ve found the right information for you. Have a look a this article excerpt from Crownbees.com:

        “Monodontomerus, known as mono, is a very small parasitic wasp that lay their eggs inside of growing mason bee larvae. You may see the female mono wasp inspecting your mason bee house flying in a zig-zag pattern. The bee larvae finish eating their pollen loaf, spin their cocoons, and die when the mono eggs hatch. Mono larvae are then hidden within intact mason bee cocoons and can be hard to detect until the following spring as you discover why your cocoons did not hatch.”

        Here is the link to the source article for more help – https://crownbees.com/faq-central/post/mason-bees-remove-and-protect.html

  4. Hello, it seems my mason bees flew off and never returned. I live in San Diego, Ca. and I set the houses and released the cocoons late February. Did the birds eat them? Will they return? Any advice would help, thank you.
    Also, I had to buy modeling clay, is that appropriate?

    1. I think a few things might have happened here. Most likely they just left but if the cocoons weren’t protected with fine mesh netting, then the birds would have gotten them as well. Also, the modeling clay isn’t the same as natural mud, it wouldn’t have been usable to them. They need a wetter, softer, muddy texture for them to use it easily.

  5. Hi, Stacy,
    I am blessed to have the gentle Mason bees and recently purchased a Mason bee house but IS IT TOO LATE TO HANG THE HOUSE? As I began saving the precious bees from drowning I realized that I needed a water feeder with stones and just as you described they drink from being perched on the stones!

    Also I have seen yesterday a WASP drinking from their nectar and the water. WHAT CAN I DO TO PROTECT THE MASON BEES?

    THANK YOU,

    1. Hi Lora
      They appreciate the water source, well done! There’s still time, it’s ok to hang the house now.

      Wasps are a problem for mason bee larva, they love to eat them. To protect them, once the bees have laid cocoons in the tubes then cover the entire house with very fine mesh bag.
      You can make one out of tulle or buy one here and this will protect the developing babies from being eaten by the wasps.
      The adult bees are more at risk from birds than wasps.

  6. I have had my cocoons out for 6 days. I live in Florida and the weather has been 80-93 for the last 5 days. Why aren’t they hatching?

    1. The temperature has been too hot for them to hatch. The optimum temperature for them to hatch is 55-60 degrees. This would be December or January. It sounds like the weather there is hotter than usual right now. The cocoons probably have died. I’d recommend trying again when the temperature is cooler.

  7. My mason bee nest finally had about 8 tubes filled, bamboo in plastic house, covered with 1/4 mesh and something is opening and eating the contents. I saw a black wasp once and a very small (sweat) bee another time. How else can I protect the filled tubes if the 1/4 mesh isn’t enough protection?
    Thanks. Jeannette

    1. It sounds like you have parasitic wasps eating the babies, they love them. The bees are finished their active cycle by the end of spring, the house should get covered in a fine mesh asap. I’m sorry I didn’t have that info posted! Take down the 1/4″ wire mesh and just drape a fine fabric mesh bag over it (like this one).

  8. I find it interesting that often in the animal and human kingdoms the female does much of the work. But we are all here to do our parts. Great post, I learned something today!

    1. Thank you for the comment. I’m glad it was interesting for you 🙂 It’s true, there is a very important role for each of them and one wouldn’t survive without the other no matter how disproportionate the work load is. Nature has it figured out 😉

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