Herbally Speaking,

I am sure you would love to make and create your own shampoo and body care products but don't have the time. If you add some drops of essential oils  to readymade store bought products, you can counteract some of the effects of using harsh chemicals and detergents on your hair.

Consider making your own hair rinse.  For dark hair, you can use an apple cider vinegar rinse (not for blonds & grays to use, it will make your hair darker).  The cider vinegar will rid your hair of the last of the detergent shampoo without drying your hair out or stripping it. Leave the vinegar in as a final rinse to dry (the smell will dissipate as it dries).  Rinse quickly in cold water If the smell of salad dressing does not appeal to you. The vinegar will help to make your towel softer as you wash it but can discolor or stain it over time so use a dark towel.

Stale beer is good to use as a rinse also. The protein makes it fluffy as well as a good use for stale beer left over from parties. Any remaining beer can be left outside in a shallow bowl to trap garden slugs.

Herbal teas make a good final rinse too.

The Herbs:
Calendula    makes hair shine and is great for redheads 

Chamomile helps brighten light colored hair and promotes hair growth 
Fennel    another good conditioner removing tangles 

Geranium    same as Lavender
Lavender     helps condition the scalp if your hair is dry
Lemon    will lighten blond hair and is a good scalp conditioner 
Mint    stimulates and energizes the scalp                                                         
Nettle    stimulates the scalp, treats dandruff, is also used to treat baldness
Parsley    good for dandruff and soap buildup
Peppermint Eucalyptus (Eucalyptus radiata) is good for dandruff
Rosemary    brightens dark hair, conditions the scalp and lessens oil production
Sage helps hair from graying and is a good conditioner
Thyme    a good dandruff treatment and will cut down oil production

For a change of routine consider trying one of these once a week to somewhat smooth the hair shaft and encourage stronger growth. The added break is good for your hair too.

Mayo pack: add about 5 drops of lavender or clary sage essential oil to 1 cup mayonnaise (the real mayonnaise).  Massage into the hair & scalp and let it sit for about 20 minutes before washing your hair. (Consider the vinegar rinse if mayonnaise remains in hair.)

Avocado conditioner: mash finely an avocado (or put it in a blender) and use that as a conditioner prior to your final rinse. Be sure to get out the lumps.

Protein Gel: mix 1/2 ounce plain gelatin and 1 cup mineral water until the mixture is smooth. Leave it to for a gel (not completely set). To that, add 1 teaspoon cider vinegar, 3 drops carrot oil and 3 drops clary sage oil. Massage into the hair and scalp.  Leave it on for 10 minutes then rinse thoroughly.

The normal growth of  hair is about 1/4" a month (more in some, less others).  It will take some time to see some results of nourishing your hair. When your hair starts growing faster and healthier than you expected, consider donating it as I did to "Locks of Love".