Hi steve
It's only a rough guide, to stop you emptying the whole box into a hanging basket or something. You know you're going to need a bit less than a pound, or a bit less than half a kilogram so find out what the box of FBB weighed new, guess how full it is now, tip roughly what you think you'll need into a dish or something and sprinkle it over your area, if sprinkle is what they ask you to do. You could always rig up a temporary balance like a seesaw, if you want to be ultra precise, with a bottle of water, using the known fact that a litre of water weighs a kilogram, at one end and your FBB tipped into a container at the other until the two balance. ;D
Geoff.
