If you are forced to use medium to hard water (medium to high calcium content) your choice of potting media becomes important. Dissolved solids is usually listed as ppm, parts per million. Total dissolved solids can be used to estimate total Alkalinity. Do worry about the calcium, expressed most often as Total Alkalinity (as mg calcium carbonate per liter of water). It is the calcium that is the problem, not really the pH. Most municipal water will have some dissolved calcium, the more calcium the bigger the problem for the blueberry. If you are watering only with rain water your mix will be fine. Akadama and Kanuma are not acidic enough to keep blueberries happy if you have alkaline water. The pumice, perlite & lava are great for adding aeration, they will not shift the pH of the soil much on their own. Composted for a while (one year, but less is okay).

The one component in your mix experiments that really does work well for blueberries is bark, fir bark, pine park, any bark will work. In your part of Virginia they should come in a few weeks earlier. 'Bluecrop' is considered a early main season blueberry, in SW Michigan it has first few ripe fruit usually by July 4, and 50% of the berries are ripe by July 10 or July 15. 'Earlyblue' was bred to bloom at the same time as 'Bluecrop' but to ripen a week or two earlier. It is heat that prevents Northern Highbush types from being grown in Florida, Mississippi or Alabama. Both cultivars are known to be pretty hardy and vigorous, they might have no problem at all. But I don't have hands on experience with this. They may also be somewhat sensitive to multiple week long episodes of warm days and warm nights where night time temperatures stay above 72 F.

They do need more than 90 days of night time temperatures below 40 F (4 C). In Virginia, you might have problems with these varieties getting insufficient cold in mild winters. (-29 C) possibly even through -25 F (-32 C). The vegetative buds are even more cold hardy, and will survive cold through -20 F. This means they are quite winter hardy, flower buds form in late summer, and will survive over winter through -18 F (-27.5 C) on the bushes. 'Earlyblue' and 'Bluecrop' are both Northern Highbush Blueberry cultivars, their genetics are pretty much 100% Vaccinium corymbosum. Read, follow the links, if you still have questions, I can answer. This initial post is about 2 Walmart blueberry cultivars that someone bought. Using the magic of copy and paste I will post the links to these.

I found a summary with links to different posts I wrote. Then the results are not 'All Leo, all the time'.Д«ut I have written a lot. You get better search results if you use the Thread Title only search.

Blueberry shift exchange