If I am understanding you correctly your Sunshine's did well in the gritty mix, but the berries withered over the summer? If that is the case, it's not abnormal. Lack of adequate pollination can result in flowers aborting or even fruits starting and not getting far before aborting. Likewise, fruits left on the plant past ripe will rot/wither.

Since your other BBs seemed to perform better in the 5-1-1 than the gritty mix for you I would suggest using the 5-1-1 until you feel you have grasped an understanding of why one thing works the way you want and the other does not.

It is true that in nature BB are adapated to grow with mycorrhizae, but in a container these guys won't readily establish and even if they did it's questionable what value they would add within a container. Symbiotic fungi can protect roots against pathogenic root pests, can grow into soil areas roots can't and can thus provide water and nutrients from areas roots can't grow. I can't think of any case where BB in a container would need this to do well.

If you are having difficulty keeping up with watering with the 5-1-1 mix then a 3-1 bark/turface mix may help a bit, but so would choosing a larger pot which will hold more mix and thus more water without being excessively water retentive.

JaG: Back to that discussion I'm having a little trouble letting go of ;-) I've read your prior posts about the difficulty (futility?) chasing pH around.

You really don't think the starting pH of 6.0 ish for the standard gritty mix wasn't a significant factor for the Brunswick failure to thrive? I've read now in several places that in my (not OP) extreme heat if your BB's pH is too high they will burn and wither much easier than if below 5'ish. One extension site (for Canada or Maine?) that suggested 3.9ph.

Greyslate didn't mention adding vinegar to water or using acid ferts.

JaG: That makes sense on the berries, they did start but then just withered, so I'll go with lack of pollination as the prevailing hypothesis ;) No, I have found the 5-1-1 has been much easier to manage than the 1-1-1 because the 1-1-1 dries out so quickly on the surface - which makes a large impact the smaller the pot (as you point out:) - I'll plan on potting then up. I was considering the 3-1 only because it lasts longer than the 5-1-1, and I thought it might be a balance between tapla's two amazing mixes.

cebury: Hmm, a good point on the Brunswicks ... I know that Sunshine blues are much more tolerant as far as pH. At this point, I don't add vinegar to my city water (I'm not able to collect rainwater) mostly because of the previous posts on the difficulty of chasing pH - I wasn't sure if it was worth it. More thoughts? I do use MirAcid for my fertilizer of choice with all my acid loving plants (DynaGro for the rest) along with a pinch of MgSO4.

As a confounder, I have lingonberries in gritty mix that were thriving - however they were in mostly shade (north side), so not likely as heat stressed as the Brunswicks and Sunshine (full sun, south side). Ah pH ...

Hello,

cebury, and greyslate ,

If you would like further help on this, you can contact me through the "my page" link for more information on how to reach JaG.

JoJo