I agree with Seona, my LO didn't start solids till 6 mo and we didn't do lumps till about 8 months. also my LO didn't take to lumps gradually...it was like, all puree, and then mash with some bits, and then all of a sudden at around 10.5 months he just started eating small pieces of grown up food (like rice, big pieces of pasta, even corn!). I remember we went through a phase of him not really liking the stage 3 baby food (very chunky) but stage 2 was too runny for him. So I wouldn't worry about the lumps. You could try doing finger foods like Seona suggested to see how he likes it - steamed carrots or green beans are good. They just slowly need to get used to having different textures in their mouth, but again, there's no rush.