Bob,

Here in Florida some of the commercial folks grow in half barrels and go right from 3 gallon pots to the 30 gallon pots. On most plants you are not supposed to do that but it actually helps the blueberries establish. For one they want always moist and the larger container helps with that and it keeps the roots cooler. Go for it.

ok thanks , one is in a gallon pot the other is in a 3 gallon

With most plants it would hold too much moisture. For most plants you want the soil to dry out mostly before you water again. Because the BB like moist it is a very good way to go about it. In a 30 gallon pot with a good pinebark peat mix you should never have to repot them.

berry_Bob, it will work. You will just be watering more soil than the plant needs. The directions that I followed for starting out with BB called for the following:
* Start all 4 inch to 1 gallon plants in 2 to 5 gallon containers.
* For established 2 to 5 gallon plants, choose a 16 to 20 inch container.

It was easy and worked well for me. Let us know how things go for you.