Summarize this article:

Purchase some celery from the grocery store and chop the leaves from the stalks. Use a food processor to chop them up until it creates a celery paste. The nutrients in celery will help straighten and improve the health of your hair. Pour the celery extract into a spray bottle and then add the water and shake the bottle. This will be the solution that you use to straighten your hair. As the solution sits, the water and celery extract will mix and should thicken. Once the solution is somewhat thick, you can use it. Saturate all of your hair. Continue to spray until your head is wet with the solution. Concentrate on the knots and curls as you brush your hair. Continue to brush your hair until it looks straight. Wrap a towel around your shoulders so that your wet hair doesn't drip on you. As you sit there, the nutrients from the solution will soak into your hair. Run cold water through your hair and use your hands to wash it out. Agitate your hair with your fingers and continue rinsing until all of the celery solution is washed out of your hair. Don't use a towel to dry your hair or it may frizz up and won't be straight. Instead, allow your hair to air dry. You can continue to brush your hair as it dries so that it doesn't curl up.
Chop up 10-12 celery leaves. Mix the celery juice and 1/4 cup (59 ml) of water in a spray bottle. Let the solution sit overnight. Spray the solution on your hair. Brush your hair with a wide-tooth comb. Let the solution sit in your hair for 30 minutes. Wash the solution out with cold water. Let your hair air dry.