When is too early to start solids?

I havent read all the replies but just wanted to add that there is a growth spurt at 4mths that nearly drove me mad!!! DS changed all his patterns and I contemplated formula and solids and all sorts and was ready to throw the towel in with
BFing but after a week or two of extra day feeds / night feeds my supply increased and he went back to more normal patterns. Darn hard at the time but we got through it and didnt introduce solids until just before 6mths.

If you start solids earlier then I'd also recommend sticking to fruit and vegies but not the starchy ones like potato / kumara / parsnip etc until 6mths and some say even longer cos they dont have the enzymes to break it down.