I think its the cold weather.

Yeah, have you had any cold snaps or nighttime temperatures below about 45 lately? Those will cause the plant to think winter is coming and to start trying to change color and go dormant again.

If it is ph caused, you can acidify your water untill the sulfer kicks in. I use sulfuric acid which you can get at auto part stores. Vinegar works also.

I've often wondered - over in the pool supplies they sell sodium bisulfate to reduce Ph. But how much would you use?

I think the code weather might have been the culprit. It's warming up and they seem to be reversing the reddish trend.

Should I wait till after they're done flowering to fertilize though? Or would it hurt to hit them with some 10-10-10?

Any fertilizer or pH modifier with sodium in it is not something I'd put on my plants. And 10-10-10 isn't a good blueberry fertilizer. They don't need that much P and the N is probably in the wrong form, avoid nitrate N. Ammonium sulfate, 21-0-0, will lower pH and feed the plant. If you want a more complete fertilizer get one specifically for acid loving plants. I've used the slow release Osmocote for acid loving plants with good results.

Just curiosity, fruitnut. I suspect the bisulfate would be pretty strong stuff, from the warning label.

It's probably the cold. High soil pH results in iron chlorosys in blueberries. The leaves turn yellow with green veins. If the leaves aren't chlorotic your pH is fine.

Agree with the others about the temps. I always get a red fringe on early foliage, which always clears up once the roots warm up.

I have 20 plants and most all of them have leaves with red fringes on them right now. I was told by an area grower that the plant can't properly take up nutrients until the soil temps come up and that's why the leaves are red. It is also why it does little good to fertilize too early in the season because the roots aren't actively feeding. Give it some time, your plants will come around.

Last summer I was concerned about several plants of mine with wrinkled leaves and this spring the plants mostly look fine. I'm learning that new plants and plants in the spring take time to adjust.

If I get time later I will take a few pics of my plants so you can see the red on the leaves.

RM