Some people find plain white socks to be boring and want something with a little bit of flair. Tie dyed socks are a great way to be different. With tie dyed socks, you can be absolutely sure that nobody has the exact same socks as you.
Use socks that have the highest percentage of cotton. Cotton takes in dye better than other materials. Polyester socks cannot be dyed at all and Lycra does not hold color well.
Place rubber bands on the socks about 1 1/2 inches apart from each other. If you are dying short socks you can space them 1 inch apart. If you want the entire sock to be colored, meaning no white spots at all, you can skip this step.
Drip the socks with fiber-reactive dye, using the bottle that the dye came in. One drop every 1/4 inch should be enough. The more dye you use, the bolder the color will be. Three or four dye colors are plenty, but you can use as many as you like. Keep in mind that mixing too many colors together can result in a brown color.
Let the socks sit overnight. It will work best if the temperature is at least 70 degrees F. Wash the socks the following day. Some of the dye will bleed out, so do not wash the socks with other clothing.
Use dyes made specifically for fabric. They can be bought at any craft store.