I think it's beardeds you've got, right? The only thing I've heard of to raise ph is adding wood ashes.

What's your garden soil like? Can you buy a different bag of potting mix? And use a mixture of the two?

If growing in a container for any length of time, you want a potting soil, period! Garden soil is too dense/heavy for container usage and drainage is impaired. Fast drainage should be your concern over winter, not pH - like the vast majority of other plants, iris prefer a slightly acidic soil (6.5-6.8), not alkaline conditions but they are not overly fussy in that regard. And potting soil is pretty much neutral WRT pH.

Well here goes, I will use the peatsoil compost, add some rapid raiser, because thats what the iris farm, growers do at their place, and they sell theirs....rapid raiser has low nitrogen and potassium helps with improves blooming??

Wish me luck! and dive right in!

Just remembered, grandpa had a secret plot in 1925 with peatsoil and used to grow the best potatoes in town! So I will stick with the peatsoil

Thanks for you help gals