How I overwintered ten out of ten
I have been thinking about this post for about a month, but I didn’t dare write it until spring was here for sure. But on Thursday, when a fur-coated bumble bee alighted on the patio and a bee fly examined my shoe lace, I knew I could call it.
To be more specific, I went into September with nine Langstroths, one top-bar, and three nucs. Today, with April just a breath away, I still have nine Langstroths, one top-bar, and two nucs. Not only are my colonies still alive, they are bursting at the seams. Bees are pouring through the entrances and climbing up the walls. I am elated.
Those of you who have read my blog for a while know that “overwintering” is my main honey bee interest. I usually manage to overwinter 60-80 percent of my hives. But this year I decided to “pull out all the stops.” I tried everything I could think of to help the bees make it through the winter.
The result, of course, is no controlled experiment or repeatable design. In fact, there are so many variables it would strain the organizational capacity of Excel. So all I can do is tell you what I did and why.
Before reviewing my steps, I’ll give you a quick overview of my local climate. In one of my very first posts on this blog I wrote that “all the challenges are local” and I still believe that. Beekeeping is not performed in a vacuum, and your local climate plays an immense role in the life of your bees.
I live in western Washington in the middle of the Puget trough. The word “trough” reminds me of water, and that pretty much sums it up. It rains nearly constantly in the nine-month period from September through June. It doesn’t add up to a lot—annual averages are about 51 inches—but it rains a little bit all the time. The three-month period of July, August, and September is hot and dry, dry, dry. No rain. Zilch. Nada. Everything is crisp.
Although I live at 47°N latitude, I am in USDA hardiness zone 8, which means it doesn’t get very cold in the winter. It dips down in the teens and twenties, but doesn’t stay very long. We get snow in the lowlands, but only two or three times per year. The average winter day is 40°F and raining.
So here are the steps I took to overwinter my bees, beginning in June 2010.
• By June 30, all honey supers were off my hives.
Comment: I live adjacent to a 91,650-acre state forest and the only farm crop in the immediate area is hay. So my bees forage almost exclusively on spring-flowering trees and roadside weeds. By the time the hot dry months arrive, there is almost no forage to be had. Whatever honey I get accumulates from April until June.
• During June I collected enough swarm cells to begin four nucs.
Comment: I wanted to carry one or two extra queens into the winter in case one of my colonies went queenless. So I started four nucs with swarm cells. Three of these produced viable queens. By fall I had three healthy nucs “just in case” something went wrong with one of my colonies.
• In August I treated for mites.
Comment: First off, I never use any conventional pesticides in my hives. However, if mites are a problem I use one of the all-natural products made from thymol (an essential oil of thyme) or formic acid (an organic acid.) Unlike conventional pesticides, these are difficult and time-consuming to use.
This year I used ApiLife Var (a thymol product) which requires multiple applications over the course of three weeks. Honey supers cannot be in place. But it is the timing of treatments that is important for overwintering.
The thymol and formic acid treatments should be used when little brood is present—so later is better. But you want to treat summer bees for mites, not winter bees*—so earlier is better. You have to make a judgment call. In this case, I set aside August for mite assault.
*In case I lost you here, summer bees live an average of 4-6 weeks. Winter bees can live many months—all the way into the following spring. If you treat for mites after the winter bees are born, it is too late to protect them from viruses carried by mites. In other words, a late mite treatment will still kill the mites, but only after the viruses have been transmitted to the winter bees. This way, you have gained very little. You need to kill mites in the summer bees so the hive is relatively free of viruses when the winter bees are born.
• In September, I checked the hives for honey stores. Any hives that appeared to be short on honey were given some extra frames reserved from the harvest in June, or given sugar syrup mixed with Honey-B-Healthy, or both.
• Entrances were reduced on all hives to protect them from robbing and yellow jackets.
• All Varroa drawers were removed from the screened bottoms to provide maximum ventilation.
• The slatted racks remained in place in the Langstroth hives all winter long.
Comment: I consider slatted racks basic equipment in Langstroth-style hives, so I never remove them in any season. In summer they provide a place to hang out during hot muggy days, and the queen tends to lay eggs further down on the brood frames–apparently because this area is no longer near the “front door.”
In a traditional winter hive with the Varroa drawer in place, the slatted rack adds an insulating layer of air between the brood nest and the Varroa drawer. This will not exist in the same way with the Varroa drawers pulled out. However, during cold snaps (see “weather forecasts” below) –or other times when the Varroa drawers are in place–the slatted racks again provide a “dead air” space that helps to keep the bees a few degrees warmer.
• Each hive was topped with a quilt box outfitted with four ventilation holes and filled with wood chips.
Comment: Of all the changes I made, this one had the most visible result. In prior years I always had condensation dripping down on the bees from the inner cover. This year none of that moisture reached the bees. They were dry and happy all winter long.
Originally I had anticipated having to change the wood chips every couple of weeks. As it turned out I never changed the wood chips. The ventilation holes seemed to play a big part in preventing the chips from getting soggy. About one-inch of the two-inches of wood chips got wet in each hive.
In my opinion, the combination of more ventilation and less moisture accumulation were the two most-important changes I made to the hives.
• As always, I checked my hives every day or two. I wasn’t looking for anything in particular except for fallen trees or bear damage. Usually I just walked by each hive and flicked the dead bees off the landing board.
• It was on one of these routine checks that luck played a big part in this year’s success. On December 15, just as I was about to flick a dead bee off of hive #2, I realized it was the queen. Darn! I knocked on the hive and it was loud and robust. I examined the queen: she looked freshly dead. So I put one of my nucs in a deep brood box and, using a slit piece of newspaper, combined it with hive #2.
Comment: I still haven’t opened this hive except to add feed. But when I get near it I can hear it roar like a caged lion. Luck definitely played a role here, but pre-planning gave me the queen I needed to keep the colony alive.
• I paid attention to the weather forecasts all winter long. Three times the temperatures dropped into the twenties for an extended period (more than a day or two). In each of these three cases, I inserted the Varroa drawers under nine of the hives and put both the nucs and the top-bar hive in the garden shed.
Comment: My husband convinced me the hives would stay a lot warmer with the bottom drawers in, so in very cold weather I gave them a little help. This compromises ventilation, however, so as soon as the temperatures got back into the 30s, I removed the drawers again.
The nucs were small, so I put them in the shed which is about ten degrees warmer than the outside. The rest of the time they were outside, stacked with double-screen boards between each.
I coddled the top-bar hive because it was a July swarm that moved in by itself, and it couldn’t possibly have had a lot of stores. So, when the nucs went inside, the top-bar hive went in as well. But it, too, came out as soon as the temperature climbed above freezing.
• Right around the end of December, I added a feeder rim to each hive. I placed it just above the top brood box, but underneath the quilt box. I added sugar patties to each hive during January and February.
• In mid-February I began adding pollen substitute to the sugar patties. I continued feeding pollen-enriched patties until now.
Now that it is spring and my hives are boiling over with bees, I’m already worried about swarming. Wouldn’t you know it? If you succeed at one thing, you’ve got to worry about something else.