If you have a shop around, you could amend with some lime.
Baking soda will also do, mix up a couple gallons of water and use baking soda to adjust the pH up. Not drastically, 6.6, 6.7. We don't want to shock the microbial life. The sodium bicarbonate will stick around in the soil and bring the pH back up.
PH is like earthquakes, a .1 difference doesn't seem like a lot, but it is on a bell curve.
Thanks, couple of questions.
Should I do this now (it was fed and watered yesterday) or wait for the next water and should I do with with nutes or plain water?