A.I. Root’s Cell Size

A. I. Root

A.I. Root was a pioneer commercial foundation manufacturer. He:

  • measured natural worker cell size
  • tested various cell sized foundation for bee acceptance
  • produced foundation for over 100 years
  • and his company monitored natural comb and bee size during that time

A.I. Root says much about cell size. These measurements are interesting! They show that neither bees nor foundation are artificially enlarged. He:

  • discussed cell size before foundation was made
  • also describes efforts to arrive at a workable foundation size
  • and European efforts at bee enlargement

I gathered the following points:

  • A.I. had problems getting small cell size foundation accepted by bees before foundation was available
  • there’s no more argument about diagonal versus square areas. He measured linearly across the cells
  • his first measurements pre-date any possibly enlarged bees by decades. His son’s later measurements confirmed the first measurements. No enlargement occurred after foundation was introduced
  • the 4.83 the Roots refer to, works out to about 5.21mm to 5.375mm cell size using the text’s table! That’s the foundation size range produced in the USA today!
  • early foundation makers were not impressed with Europe’s larger bee as a better bee idea, or of the need for a larger foundation. They didn’t proceed along those lines
  • the cell size measurements taken by A.I. Root in the 1873 were later confirmed by Pritchard and H. H. Root. No artificially enlarged bees ever!

Read them for yourself and see!

These pages were scanned from the 1975 edition of the “ABC and XYZ of Beekeeping”. They aren’t included in later editions.





Cell location is critical to understanding the meaning of cell size measurements. If a single measurement is taken that represents most of the worker brood cells in my top bar hive, it would we around 5.4mm. If that measurement was taken in the broodnest’s physical center, it is about 5.1mm. The same measurement taken in the core area is 4.9mm or less.

I measured some brood cell sizes on each of the 18 natural combs in my top bar hive:

  • measurements were taken across ten cells
  • only cells actually containing brood were measured
  • max/min ranges reflect the largest/smallest values
  • averages are an average of the max/min values from all combs

Maximum Worker Cell Size
Range 5.12mm to 5.59mm
Average 5.33

Minimum Worker Cell Size
less than 4.6mm

Maximum Drone Cell Size
Range 5.87 to 7.29
Average 6.49

Minimum Drone Cell Size
Range 5.25 to 6.43
Average 5.93

From less than 4.6mm to 5.59mm, that’s quite a range for worker cell size. Is foundation too large?

Other Historical Literature

Here’s another set of  historical cell size measurements from David Heaf. What do you think? Have cell sizes been artificially enlarged?