From what I've learned from our pediatrician and experience with my now 1 1/2 year old daughter, it depends on what he is ready for, and always be careful--my daughter choked quite a bit learning to eat thicker foods. If he's only had SOME jar food, I would suggest waiting until he has been eating it regularly for some time. There's no need to rush him to eat chunkier/thicker foods. Once he's had the 1st stage foods for a while and seems to have 'mastered' eating them, then you could start introducing 2nd stage foods. Always be very careful though--both my mother and mother-in-law tried to feed my daughter thicker foods before she was ready and she choked. Luckily she was fine, but it was very scary. She also choked on other occasions just getting used to the new textures, and it made me feel like a bad mom that it happened so often, but I'm sure it's a pretty normal thing for babies figuring it out, they just need you there to help them! Also, the 1st stage foods are single-ingredient so you can make sure your baby doesn't have any food allergies, so it might be a good idea to give him a wide range of 1st stage foods so that when you introduce 2nd stage, you can use 'process of elimination' if he does have an allergic reaction to figure out what it's from.