Coloring is one of those things - there is no right time to start, you kind of just have to dive right in and see if your kiddo is ready. Some people start as early as 9 months, others wait till their kiddo hits the one year mark. If your toddler shows interest in coloring then he is probably ready, but if he just wants a waxy snack, then it is best to wait a few more months and try again. Eventually he will get it and it will become a nice pastime for him and you.
When you decide it is time to see if your toddler is ready to attempt coloring, you will need a few things to get started. Purchase large, chunky crayons so that he can grasp them with his chubby little hands. You will also need a large pad of plain white paper, or a roll of butcher paper. Seat him at the table and tape down a large sheet of the paper, or if you have hard floors spread out the paper and tape it down so it doesn't slide around when he is trying to color. Take out a few crayons and show him what to do. Say "Look Skyler, Mommy is coloring with the blue crayon! Can you try?"
Why it's Important
IT is such a simple thing, yet coloring is great for your little guys development. Holding those chunky crayons and scribbling on paper helps him develop those fine motor skills that will help mature the muscles in his fingers and hands. This will help him down the line when it is time to brush his teeth, use a fork and write. It is also key in developing the understanding that lines and markings can represent concrete objects, which is the foundation of early reading and writing. Additionally it helps your kiddo gain independence and have a creative outlet for emotions and frustration.
Coloring is a great way for kids to start to differentiate colors. Most of the fat crayons come in boxes of eight with the colors: red, green, blue, brown, black yellow, orange and purple. Kids Health states that by the age of three "Your child also should begin to identify colors." At 18 months, he should be able to recognize different colors, and name at least one by 36 months. To encourage his learning, show him. "Mommy is drawing a blue flower, can you draw a red one?" When he is right give praise and reiterate, "Wow that is a beautiful red flower!" However, if he draws a green flower, don't correct him. Instead say in an encouraging tone "That green flower is so pretty!"
Staying Inside the Lines
Coloring inside the lines is not as important as one thinks. Those crazy scribbles that he loves making is linked to literacy, where as coloring inside the lines doesn't help in that aspect. The more scribbling he does the easier reading and writing will be. That doesn't mean ban coloring books, just limit them and encourage your little guys creativity. Pretty soon your kiddo will be drawing recognizable objects and that is a sign of early literacy!
I used the following forums to estimate the time frame on the appropriate age to start coloring.