A handful per square metre is all very well, but hard to do - you get another handful from the bag and can't remember where the last lot went. I always get 4 garden canes and fasten them together with twine to make a metre square, then move it AFTER I've got the next handful, so i can see where I've already been. Same applies with lawn dressings and weed and feed. If I had the money I'd get one of those fancy spreaders.