Just because there is a little algae growth on the soil doesn't mean the roots are hurt. How do the plants look? How long do the drippers run each day?

If the mix is well drained, the plants are likely fine.

The Fruitnut

the blueberry (misty) did leaf out, but just a little bit, no new shoots yet, and it's 3 month after planting. the soil is well drained. the drippers run 4 min every two days. the southmoon blueberry with identical care (no algae though) has absolutely thrived.

You said "the drippers run 4 min every two days"

That's not near enough water for anything. And to prove it, do the math.

First, what's the dripper's output? (Let's say 1 gph to keep it simple.)

So, if you run the system for 4 minutes, you get 4/60th of a gallon, which reduced to lowest common denominator is 1/15 gallon.

Next, check to determine how much of the planting mix is moist. To do so, stick a finger, or trowel, in it.

Bottom line: You'll need to dramatically increase the run time.

jean001,

you are right that 4 min is not enough. I actually deep water them every 2-3 days in addition to the drippers. I don't think my blueberry plants are starved of water.