There are several home remedies for split fingernails, most of which are focused on preventing new split nails from forming. The key to treating split fingernails at home is moisturizing and strengthening nails so that they don't suffer further damage.
One method for treating cracked nails is to avoid excess moisture or harsh chemicals such as soap, hand sanitizer or cosmetics. When using nail polish remover, opt for a formula with no acetone. All these substances can dry out nails and cause them to split. Additionally, keep nails trimmed and well-shaped so that they are less likely to break or catch on surfaces with which they come into contact.