Events
Heavy Man!
By John Whitaker
When we start beekeeping it is difficult to resist having a peep inside the hive every other day. For the new beekeeper this is fine as it is part of the steep learning curve that we all must go through. But for the poor old bees it is a disruption that is unwelcome. It is a disruption to both brood rearing and foraging. The retention of nest scent and heat is important for promoting the health of the bees. The Germans have a word for it – nestduftwarmebindung.
As we gain experience we learn to minimise the number of occasions when it is necessary to open the hives. I’m not advocating leave alone beekeeping. It is still necessary to check for foul brood twice a year and swarm prevention requires that we regularly look for queen cells in May and June.
As the years go by I find that I am visiting my bees more often, but I’m opening the hives less frequently. Leaning on the gate or slowly strolling about the apiary watching the comings and goings at the hive entrance can often tell us just as much about the strength and wellbeing of a colony as looking inside.
There is another non-intrusive technique that can be used to assess a colony of bees and that is weighing. It is possible to buy weighing platforms that can be put between the floor and the hive stand and which gives a continual reading of the weight of the colony. This is an expensive piece of kit and I have been tempted but my instinct of keeping my wallet deep in my pocket has always prevailed. A much cheaper and flexible option is to use a spring balance, at the cost of a couple of jars of honey. These are calibrated in pounds and kilograms. I now work in kilograms. To use a spring balance a screw eye should be put into each side of the hive floor. The spring balance is then used to gently lift the hive, easing one side off the stand. The reading on the spring balance can then be doubled to give a good approximation of the weight of the hive. A more accurate value can be obtained by weighing both sides and adding the two values together. I always remove the roof as roofs tend to be heavy and vary in weight.
If you are to interpret the weight of the hive it is necessary to have a number of data items tucked away in your head, ready for use in the apiary but not to be brought out during dinner parties.
Weight of a brood box plus empty frames – 7kg
Weight of a super plus empty frames – 5kg
Weight of bees – 7700 bees weigh 1kg, and therefore 40,000 bees weigh 5kg
Weight of honey in a super – 12kg
Weight of wax in a brood box – 1.5kg
Weight of floor plus crown board – 1kg
Weighing is particularly useful during the Spring build up. During March the weight will be continuing to decrease and it will be possible to monitor whether Spring feeding is necessary. From mid April onwards the weight should start to increase, quite rapidly once the OSR comes into flower. Later on the weighing technique can be used to assess
a) whether additional supers are required
b) whether hives have sufficient stores during the June gap
Though most beekeepers are numerate I will go through a couple of examples of the mental arithmetic required.
1) to ensure that a colony is heavy enough for the Winter. Consider a colony in a single brood box. To survive the Winter the weight should consist of
Floor and crown board 1kg
Brood box and frames 7kg
Wax in brood frames 1.5kg
Bees (15000) 2kg
Honey 18kg
Total 29.5kg – i.e. between 14 and 15kg when hefting a single side.
2) to ensure that a colony has sufficient stores to survive a dearth in June. Consider a colony with a brood box and one super. Its minimum weight should be
Floor and crown board 1kg
Brood box and frames 7kg
Super and frames 5kg
Wax in brood frames 1.5kg
Wax in super 1kg
Bees (40000) 5kg
Brood (20000) 2kg
Honey (sufficient to ensure survival for a week) 5kg
Total 27.5kg – that is between 13 and 14kg when hefting a single side
This might seem complicated but in fact you can soon do these calculations mentally, almost automatically.