Intro Apple Juice

Apple juice is for babies at least 6 months old. Cereal can be started earlier but apple juice can really tear up their tummies if given earlier. Since you didn't say how old I don't know what else to say, good luck!

My DD didn't care for cereal much either, I tried using my milk and water and she didn't like it either way... I just mixed about a tablespoon or two of apple juice in with her cereal and water, just enough to add some flavor. She chowed it right down after that! She hasn't had any issues with only eating sweet things.... I figure (health-wise) a little bit of juice isn't any worse than feeding her applesauce. I still don't give her juice to drink though...

I would suggest just plain water. They don't need the sugar in apple juice. I don't pump enough either so water is what I have used for all 3 of my kiddos.

i don't know how old your son is, but if he is old enough for apple juice i would do just what you suggest because my oldest two had skin reactions to apples and apple juice until they were about 3. otherwise just use water. adding breast milk or formula is just to get more nutrients and calories into the baby. but i doubt your baby is eating enough cereal for his health to suffer if you only use water in the cereal.

If you start using apple juice, you will only succeed in teaching your son to only like sweet things. The juice will sweeten and flavor the cereal, even if you use a 1/2 juice and 1/2 water mixture. I would just keep mixing his cereal with formula and he will get used to it. If you must use something else, use plain water, not juice.
In answer to your question however, if your son hasn't had apples yet, then you should introduce the juice for 3-5 days before introducing another new food.

Baby cereal is nasty, have you tried it? I put a tiny bit of applejuice in with my daughters cereal, but mostly used water. I remember also mixing it with unsweetened applesauce.
Even though I did this, my daughter always prefered the veggie baby foods to the fruits. I think a preference for sweets comes if they get too much as they grow older.
How old is your son? Try it with just water and if that doesn't work, try the juice. Do what you think is best, you are the mom.

I would skip the cereal entirely. He doesn't need it and if he's not interested you can just feed fruits or veggies instead. I started my son on bananas, sweet potatoes and avocado when he started solids. He did eat cereal eventually, but mostly oatmeal mixed with plums or applesauce.

NO JUICE until AFTER ONE YEAR! Just use water. The combo of flavors of formula and ereal might be what he doesn't like anyway.