I dont think you need to worry about the size of the barrel I have my blueberry plants in the yard, just remember to spread about 2 tbs if 10-10-10- furt. around under where the drip line is, as they begin to leaf in the spring ang again in the fall after the leaf fall.

Blueberries are much like potatoes in that they require lots of water for best results, but won't tolerate wet feet, so over-potting is a danger unless your soil drains very well. You can grow small plants in large containers in a fast soil, but you could easily be over-potted (at least until roots colonize the entire container) in a slower soil. Do you see the relationship between plant size/ container size/ soil drainage?

No one can give specific advice w/o knowing your soil. It would also help to know if your containers will be placed on the ground (on soil) or on a deck or cement, etc. If on the ground, you may be able to take advantage of natural wicking & allow the plants to remain in the barrels.

There is no real formula for determining what size container is appropriate for a plant. As you gain growing experience, you'll become more confident in judging appropriate combinations of soil, plant material, and container size. IOW, as time passes you'll move from taking WAG's to taking more SWAG's. (If you absolutely NEED to know what that means, you'll have to mail me.) ;o)

Al

Thanks Al, I was hoping you'd respond. I'm fascinated by the ideas your posts have introduced me to, never having thought much about soil structure before (and being new to container gardning of anything but annuals).

"Do you see the relationship between plant size/ container size/ soil drainage?"

I sure do. If the soil doesn't drain well and the pot is too big there will be large areas towards the bottom of the pot that stay wet and anaerobic, so roots won't colonize them, right?

I have heavy clay soil in my yard, but I've amended a lot of it for garden beds. I took some of that amended soil and added perlite, peat moss and lots of compost. I know you're probably cringing now! I was making the mistake of trying to replicate good in-ground soil thinking it would be good for the containers too.

It's been consistently rainy around here (March near Seattle) and the soil seems to have been moist this whole time. Probably not a good sign right? I want to repot the whole shebang in your soil mix, I just don't know if it would be a mistake to do it in such big containers at this time.

Kristin

I forgot, but I was going to say that the barrels are on my concrete porch, and I raised them up on bricks.

The root balls of both plants are gallon pot size, I would say. Maybe slightly bigger.

Realize that blueberries get pretty decent size; you half barrels should work out just about right. Remember they like acid soil like rhodies do; use the same fertilizer used for rhodies and azaelias. WSU has very good write-up on growing them. I'm over on the Kitsap Penninsula BTW

Here is a link that might be useful: WSU berry page