1. Lemons
Lemon juice, diluted half and half with distilled water, will lighten dark blond or light brown hair and won’t leave reddish tones unless your hair already has them.

2. Vinegar
Vinegar, like raw apple cider vinegar, will leave reddish highlights in the same hair color. Mix apple cider vinegar 50/50 with distilled water. Spray on all over to lighten all of your hair or apply with a cotton ball or brush for strands of highlights. Leave on 30 minutes and rinse out. Dry as usual. (Of all of these options, I’ve used this method the most. I have naturally reddish tones to my hair and try to keep it looking natural.)

3. Peroxide
Dilute hydrogen peroxide half and half with water as well. Apply as directed above and test after 15-20 minutes. Peroxide will lighten quickly without the worry of drying out like commercial hair bleaches. Wash out well after you get to the shade you want.

4. Chamomile
My grandmother used to swear by chamomile to lighten darker hair. She said to brew a really strong cup of chamomile tea and let it cool. Then apply to individual strands of hair for highlights, or pour over entire head for all over color. Go out into the sun and let it dry, usually about 30 minutes. Wash out and style as usual.

5. Henna
On most hair, henna will only darken, but on very dark brown or black hair, henna can lighten and leave reddish highlights. Use about 3 tablespoons of henna powder to ½ cup of boiling water. Let this sit for 12 hours or overnight. Then apply to your hair and let sit for 2-3 hours. Wash out well and style as you normally would.

Source: DIY Natural Blog Post