Nails have a steady growth rate of about 3.47 mm per month, according to research at the University of North Carolina, and in some cases ways must be sought to protect them from cracking and brittleness,  and according to what a nail specialist said, the rate at which nails grow cannot be changed However, nail growth can be affected by several reasons such as: temperature and hormones,  and nails can be strengthened and preserved in several ways and recipes, including:
Olive oil and lemon
Olive oil is one of the best natural moisturizers for nails, skin, and hair as well. Lemon juice contains antioxidants and vitamin C, which protects the nails , removes stains from them, and stimulates their growth stronger, and it can be used by: 
- Mix three tablespoons of olive oil with one tablespoon of lemon juice.
- Heat the mixture just above body temperature.
Soak the fingertips in the mixture for ten minutes.
- Repeat the process daily to get the best results.
Dead sea salt with water
The original Dead Sea salt contains more than 20 types of beneficial minerals, most of which have good efficacy for improving nail health. It can be used by: 
- Dissolve a tablespoon or two of sea salt in a small bowl of warm water.
- Add a few drops of moisturizing oil to it, such as: olive oil, vitamin E oil, or flaxseed oil.
- You can also add one or two drops of lemon, lavender oil, or rosemary oil - optional.
- Soak the nails with the mixture for (10-15) minutes.
- Wash your hands with warm water, dry them, and then moisten them.
- Repeat the process three times a week, to get stronger, healthier nails.
Vitamin E with essential oils
Vitamin E is one of the essential elements beneficial to the health of nails and hair, and it can be used to increase the growth of nails, by adding one of the essential oils, such as: tea tree oil, to vitamin E, and mixing them together, and then heating the mixture a little, and dipping the nails in the warm mixture, and leaving it on Nails all night. 
- Brown (23-9-2017), "20 . Top Menu Home Remedies For the Natural Nails Growth , the At Menu Home" , Www.vkool.com , Retrieved 11-12-2017. Edited.
- Michele Bender (2-8-2010), "Want Strong, Healthy Nails?" , Www.goodhousekeeping.com , Retrieved 11-12-2017. Edited.
- Janice Taylor (9-6-2015), "15 Menu Home Remedies For The Healthiest Nails You'll Ever 's Experience" , Www.naturallivingideas.com , Retrieved 9-12-2017. Edited.