I've got a blueberry in a pot that was repotted without amending the soil. Now it seems to be growing okay but rather then repotting it again, I'm wondering if I can apply a coffee grounds mulch while it still has a few berries, and i mean only a very few berries compared with the numbers on it when i bought it just on a year ago. Or should I wait?
I haven't tested the soil pH, and I don't use tap water for watering, but fish water from my gold fish. I did put some citrus fertiliser on it once late last year, and we're now in mid summer.