I tried a new bee last fall - the NWC. From my readings, they tell me to beware their buildup - they build up fast, fast, fast in the spring. So, I'm sorta clueless as to when I might need to add another box. When dealing with the Italians, I was pretty safe till April, but I did do a checkerboard in February last year, I think. Can anyone tell me what I should be looking for this spring for these girls? Right now they are in a 3-high nuc, 5 frames each, mediums.