How long does it take for foot fungus to begin growing?

See below. Almost immediately after contact. Often times good hygiene will stop the growth.
Varies. From a few days after exposure untilvseveral weeks or months before it becomesxobvious. Heat, sweating and your location immune system will determine how fast the fungus will spread. Initially it can be treated with over the counter creams such as lamisil, (terbinafine) mica tin. If not responsive, prescription creams or oral drugs cab clear your fungal infection.