J.C.
You will know it is time when the baby can move the food from the spoon to the back of his mouth and swallow without gagging. This is developed anytime after 4 months. Start with very thin rice cereal, and if he/she can not swallow without gagging, wait a few days and try again until they can. Once you get him taking rice cereal well, you can start to thicken it, and than move to other foods. Mine both started solids at 4 months and where very ready.