When are inner covers worthwhile?

[omnimirage]

I've never been taught to use an inner cover, rather to use a "hivemat" instead. I see a lot of people use inner covers, but surprisingly, I can only find a limited information on their actual uses, advantages and disadvantages. I'm wondering if it'd be worthwhile to invest in inner covers for my hives.

Under what circumstances would it be best to use an inner cover? Under what circumstances would it not be best to use one?

[Perry]

Not familiar with mats, but I think I get the idea. The inner cover serves the purpose of being able to get the telescoping cover off without destroying it. There may be some slight insulative quality to it as well, but probably not much.

[Lburou]

Perry put his finger on the prime purpose of the inner cover (the British call it the crown board). 

Inner covers have worked for me wherever I've kept bees, (very cold weather in Alaska to very hot weather here in Texas).  I use a little kerf in the edge of the inner cover to ventilate the hive.  Ventilation is, in my view, important to successful hives all year around.  It also functions as a humidity buffer by absorbing moisture when its humid and releasing it when the air dries out. 

I have also (rarely) used a seed bag in the place of the inner cover, but that reduces ventilation; and rising, humid air creates condensation on the bottom side of the plastic bag -in winter, this can be a recipe for disaster if the condensation rains back down on the cluster.

Omni, did you make a plan for fixing the joints in your hives?

[omnimirage]

Interesting to know. The mats also act as a barrier to prevent the comb sticking to the roof, but it doesn't provide these insulation/ventilation benefits.

I'm not going to fix the joints as I believe the rabbit joints are fine. I am going to replace all my working hives with ones that have screws in them, though.

[LazyBkpr]

   The inner covers I use are reversible, a shallow side on one side and a 2" deep side on the other. the shallow side is for summer, and prevents the bees from gluing the lid down as Perry mentioned. I also have a hole in the center of my inner covers that I can put a jar of syrup in, OR, put a gallon bucket over. Then it is easy to feed when they need it without actually opening the hive.

   The deep side is for winter, and allows space for winter pattys/sugar cakes etc...   winter emergency feed if they need it.  I can also store my 2" foam in the deep side for summer, and prevent some heat from entering the hive, fliup it over for winter and put the foam on the shallow side with the tele cover on top to keep the lid from condensing moisture.

   I have mats, I tried using a mat on a single hive...   First, I did NOT like the fact that it sagged down on top of the top bars, preventing the bees from crossing over the top, if they needed to get to the other side they had to go back under..
   Second, the bees glued it to the top bars wherever it touched them and required peeling off.  After that I never put it back on the hive again.
   
   I am not saying DONT use them, because we all have our own preferences...   I was drawn to them because they were cheap.  If they work for you, then go for it!

[iddee]

There's cons to the reversible inner covers, too.

http://www.worldwidebeekeeping.com/forum/index.php/topic,5795.0.html

I prefer the standard inner cover.

[LazyBkpr]

Yikes...   have had them start to build comb when we had an early spring... and I didnt get them flipped in time, just not that badly yet...   YET..  Give me time!

[apisbees]

In cold climates Inner covers are a convenient way to provide winter ventilation and an upper entrance other wise you may need to drill holes in the end of the upper super to provide them. From previous posts, you live in a region that is fairly mild during the winter so a upper entrance and added upper ventilation is not needed so the hive mats work well for keeping the bees from propolising the lid down. My recommendation If it ain't broke don't try to fix it. We use them because we have to with snow blowing up against the hive burying them and over 5 deg of frost during a long part of the winter.