Probably not that great for dark hair but blondes who go to dark do this. Buy a couple of lemons and squeeze them into some conditioner. Put it on your hair and wait about thirty min. Then wash it out. It will take out the color. But, that's not what you need. You've lightened your roots with the developer and heat from your head.
Temporary hair disaster and how a lemon saved my life (long and pic heavy)
What happens is if your roots turn then it lightened them from the heat of your scalp. I would use a demi permanent color with a low volume developer because you just want to add color. Just because it was darker than your hair doesn't mean it wouldn't lighten, lift and deposit.
https://www.esalon.com/support/categ...-formulations/
You just want to deposit color. ^ If you have a beauty supply chain go there and ask for a demi permanent color, and buy a 10 volume developer. It will wash out over time and you'll have to repeat it but and least it won't turn your roots orange.