Hi! I've seen many designs for bee hotels, and it seems like they really just need holes to live in. If i were to drill a bunch of holes into some pine or holly logs that I have lying around, would this suffice for a bee hotel? How big should the holes bee, and how deep?do I need to make sure to provide anything else (besides flowers) to get bees to move in?
Holes between 1/8" and 1/2" work. Different sizes attract different species of bees and/or wasps. Around here, the leaf-cutter bees are most happy with 15/64, but that's close enough to 1/4" that I use the slightly bigger bit. Predatory wasps use the 1/8 and 1/2 in holes. Mason bees use 1/4" holes.
I drill holes as deep as my drill bit, or as the wood, whichever is deeper. Sometimes that is as shallow as 1.25", or as deep as 6".
Getting the bees to move in is iffy... Sometimes nothing will use it for years, or one size hole will fill up, but not other sizes. Other times, every hole will get filled immediately. Depends on what species are in the area, and how desperate they are for accommodations. Old wooden barns tend to have lots of hole nesting bees in them. Setting up a nesting box in the barn is the easiest way I have found to collect lots of bees that can be moved during the winter to a new home.
In my garden, the leaf-cutter bees really go after the sunflower pollen. The predatory wasps really appreciate carrot, parsley, parsnip, fennel, and onion flowers.
We can always count on Mr. Lofthouse to having good advice.
I thought I saw it somewhere on Permies about providing a good water source for bees where they can drink and not drown.
When I lived in Surprise, AZ my aboveground pool was a huge hazard to thirsty bees.
I found this interesting article with a water jug bowl combination used to water bees, the article talks about training your bees where to go for a drink.