What is the best bee-friendly exterior finish for hives?

I'm getting bees again! Yay! It's been a long time, maybe 15 years since I kept bees before. I have ordered a nuc which will be available around the beginning of June. In the meantime, I need to prepare a hive as all I kept was my personal gear.

As we are flat out busy here with other homestead projects, I am just going to order standard hive components for assembly rather than take the time for a home-made solution. (I think as a very out-of-practice beekeeper who wasn't overly experienced even back then, that will give me my best chance of success. Also easier to get advice from local beekeepers if my setup looks reasonably standard. I may get more creative as we expand to additional hives after I regain confidence in keeping bees alive and happy. In future, I think it might be interesting to experiment with some of the traditional frameless setups for bees, but keeping it simple for now.)

I'll need to put some kind of protective finish on the exterior surfaces of the hive boxes. I hope to have the boxes ready for the finish about two weeks before the bees arrive. Way back, I used an exterior milk-paint which is no longer available. Whatever I use now will need to be bee-friendly, presumably low or zero VOC, and compatible with organic farming. The climate here is very wet in winter (almost daily rain from late fall to early spring with a couple of weeks of snow here and there) and bone dry in summer. Does anyone have a favourite paint they would recommend for those conditions? I'm also open to finishes other than paint, provided they are sufficiently protective and bee-friendly.

both ecos and safecoat brands are supposed to be good

I like pure tung oil. takes a long time to cure, but it looks nice and protects well. I also like how it smells while it's curing.

a mix of a drying oil and beeswax is another option. boiling in straight beeswax works, too, as does heating the wood before painting melted beeswax on to improve penetration.

my favorite is kakishibu (fermented astringent persimmon juice), but that's not the easiest stuff to get ahold of in most of the world.

Thanks Bruce and Tel for those ideas.

I think I'll go for the tung oil rather than painting, as I already have some here and that will be one less store to go into in these days of COVID (the bee supply store will be a pre-order and pickup from their driveway as they're not allowing anyone inside). I bought a can of tung oil to use on the wood countertop on my kitchen island and hadn't gotten around to that project.  It should look very pretty on the beehive, which will be located next to our main veggie garden and fruit trees and highly visible from the house.

According to what I see on the internet, the advice for external use appears to be that about 5 coats of tung oil should be applied and the dry time would be about 2-3 days per coat. Does that sound right?  What I have on hand is straight tung oil, not mixed with a varnish. Is an annual touchup of tung oil required? I assume that should be done with the box removed from the hive rather than with the bees in residence? In which case I guess I'd need a spare box so as to be able to swap them out when touchups are needed.

Andrea Locke wrote:According to what I see on the internet, the advice for external use appears to be that about 5 coats of tung oil should be applied and the dry time would be about 2-3 days per coat. Does that sound right?

that sounds fine. the final cure might take substantially longer than that to finish completely, but I don't think that would be a real problem unless you expect the hives to remain wet from rain for long periods of time this summer.

Andrea Locke wrote:What I have on hand is straight tung oil, not mixed with a varnish. Is an annual touchup of tung oil required? I assume that should be done with the box removed from the hive rather than with the bees in residence? In which case I guess I'd need a spare box so as to be able to swap them out when touchups are needed.

maybe not required every year, but probably occasionally to maximize the longevity of the boxes. just keep an eye on the condition of the wood, especially when you cycle a box off the hive for harvest or some other reason. in my experience, it's rare to be using every last box. if I do find myself in that situation, I generally build more.

it's probably possible to apply another layer while a box is still on the hive, but I could see that going wrong in a lot of ways.

in any case, a hive roof with relatively large eaves will keep a lot of rain off and reduce the amount of maintenance required. several other advantages, too.

Thanks Tel. We're going into the dry season here, so I think the curing should be ok. If need be, I have a market tent shelter on hand that I can quickly pop up and put over the boxes if it looks like rain. But by the first week of June when the nuc will be coming it might be bone dry with no more rain until the fall. And until then I can keep the boxes curing under cover.

You confirmed what I suspected, that trying to touch up the boxes with tung oil when bees are living in them could go horribly wrong :)  We'll be sure to have extra boxes on hand when we get to that point.

In wet climates, protecting the box from rain is almost as important (if not more important) than painting the box. Creating a 4" overhang on all sides of the box will go a long way to extend its useful life (and the life of whatever finish you choose).  This cover can be a piece of corrugated metal cut to size, placed on the hive top, and weighted down with a heavy stone.

I had dozens of hives treated with quality tung oil (attracted, like you, by its naturalness and the original pretty look of the boxes), and after seven or so years of use I don't recommend it.  Not only you need to re-apply it at least every other year to renew protection (which can be tricky when you have bees inside), but the oily surface has created a medium for mold growth (the boxes look dirty after 1 year and black after 2 years). This is in the Missouri Ozarks, which may not even be as wet as where you are. In climates that are dry year-round, beekeepers are using linseed oil successfully, but I don't think an oil wood finish is the best choice for a climate with a wet season.  After 7 years of use, the hives treated with tung oil do not look as nice, and have not held up to the elements nearly as well as the ones painted with flat exterior acrylic house paint, which is what I'd recommend.  Having a hive roof overhang and/or hive constructed of rot-resistant wood species such as cedar is another alternative.

Thank you, Leo.

I've already committed myself to the tung oil - have four coats on there now and was going to put a fifth (and probably last) on today. Bees are coming in early June, so I'm up against a time crunch to get this done and any VOCs off-gassed. Tel, who is in a similar climate to me (about 250 miles due south), seems to have been using the tung oil successfully for a number of years. Typically here the wet weather is in the winter and the summers are bone dry, so I think mold is going to be less of a problem than in your climate - I'm guessing Missouri Ozarks would be humid in summer.

I am assuming that tung oil will need regular upkeep so as long as I don't have issues with mold and such, I will just plan for a maintenance cycle and have enough boxes etc on hand to make that feasible. If I run into problems I'll sand it down and paint.

The solution you are suggesting for increasing the overhang is one that hadn't occurred to me. Brilliant in its simplicity! I have scraps of steel roofing in my stash, and an endless supply of large rocks, so I will definitely put the larger overhang on for winter.