There's nothing more unsightly than big black tramlines on bright blonde hair 6 weeks after you're appointment at the hairdressers.
If you want to spread out your hair appointments saving you money and the condition of your hair there are a few nifty at-home tricks you could try...
1) Naturatint in Light Dawn Blonde - This mild colourant available from Holland & Barrett has no ammonia, a little bit of Hyrdogen Peroxide and natural extracts to gently lighten hair with minimal damage. Once you mix the colour up apply only to the roots. Then after twenty minutes apply the formula to the rest of the hair for a 'brightening effect'.
2) John Frieda Sheer Blonde Lightening Spray - This isn't one to use on a daily basis as it does contain Hydrogen Peroxide and a hairdresser friend of mine says it can leave a greenish tinge on very light blonde hair if it's daily. I would advise just using on the roots. Simply spray the product onto wet hair and blow dry.
3) Batiste Dry Shampoo with a hint of colour (blond) - If these products containing 'Hydrogen Peroxide' all seem a bit scary, a simple and temporary measure is this dry shampoo. The lemon coloured powder will disguise roots until you can get to the salon again.