Here's all you need to know from Oregon State University

http://extension.oregonstate.edu/catalog/pdf/ec/ec1304.pdf

Here is a link that might be useful: Oregon State University info re blueberries

I think you are more concerned than you need to be. Blueberries thrive in western Washington, both in home gardens and in large, commercial fields. They are even used as ornamental plantings by the neighboring city in their large mixed sidewalk planting beds and I can guarantee these do not get any special attention other than weeding and annual pruning! Blueberries are quite tolerant of a range of acidity and they produce just as well in our moderately to slightly acidic soils as they do in those that are more highly acidic. If you can grow rhododendrons - and what western Washington resident can't - then you can grow blueberries. They do like a soil that is pretty organic and fertile, so I'd amend the entire planting area with compost before planting and mulch with more compost after planting. It won't hurt to add peat or sulfur either, if you wish. If you add sulfur, 1-2 lbs per 100 sf is sufficient.

It's rather interesting that the OSU article cautions against the high water table.......there is a commercial blueberry farm not far from me that is planted on the edge of a slough. The water table is quite high - to the point where the ground is squishy in winter, even boggy. This field has been in active production for more than 50 years! (it is on the local historic register). I worked there when I was in high school some 30+ years ago and it was an established, thriving concern long before that.

As an aside regarding the attached link discussing this farm, the 1994 lease issue was resolved with the local parks department by getting the site named to the historic register. I added it for specific note about the location of the farm and the soil conditions it enjoys - moist, mucky but very organic soil. btw, this is a certified organic farm.

Here is a link that might be useful: Overlake Blueberry Farm

Thanks! Those are some great links!

I am located in the extreme northwest of NW WA, & I see the blueberry fields in the Skagit flats every time I drive south. My place is not as moist & mucky as that, but before it was cleared & drained (~100 years ago) it was an alder bog, so the native soil is what I have always dreamed of. Definitely I will add compost, as usual, & a sawdust mulch.

Q: "If you add sulfur, 1-2 lbs per 100 sf is sufficient." Does this relatively small amount need to be tilled in now & allowed to mellow over the summer, or can I plant immediately after tilling in the sulfur? And (you seem to be pretty knowledgeable!) can you suggest a "this summer" green manure crop that won't mind the sulfur?

You can plant after adding the sulfur - just work it into the soil with the compost when you amend the planting area. It takes some time for the reaction to lower the pH to occur but if incorporated into the soil, it won't hurt the plants.

As to the cover crop, is this for a different area? Because you can plant the blueberries as soon as you prepare the soil if you wish. Most cover crops are planted in fall to protect and improve the soil over winter but you could plant something like red clover to summer over the desired area. See what's available now at your local nursery or ag supply store.

It was said "It's rather interesting that the OSU article cautions against the high water table"

Well, although I don't know the reason why the authors added that phrase, I do know that blueberries can die of root rot in overly wet soil.

Blueberries are one of the recomended shrubs for rain gardens in our area. I think that the difference is that where the soil remains constantly wet certain types of blueberrys will have root rot. Writers have referrenced picking in blueberry bogs which may be a wet spot or only a name for an acid area.

It was said: "Blueberries are one of the recommended shrubs for rain gardens in our area"

Rain gardens are designed to drain. That is, they don't remain constantly wet. Thus the bushes get the water they need but don't drown.