Sawdust will do that. And be careful that it's not treated-wood sawdust.
While cottonseed meal is a good source of nitrogen, it's fairly slowrelease
and very low compared to what the sawdust can soak up. I'm not positive
about this but I know I read it somewhere, that blueberries are plants that
cannot distribute fertilizer to the whole plant if applied only to one side
whether foliar or root feeding. And if you have a good mulch on them,
ammonium nitrate is a good nitrogen source and not too strong (if used
properly -1/4 to 1/2 cup per plant I believe depending on size). Blueberries
are wonderful stuff.
Gary

"Phisherman" wrote in message
...
My blueberry leaves were turning a light green, showing their veins.
The blueberries were fed cottonmeal and given a thick mulch of old
sawdust. I decided to give the plants a (half) dose of Miracid three
weeks ago, and the bushes have responded with a deep green color and
loaded with berries. Wow! The change was amazing. I was a bit leary
of fertilizing the bushes due to damaging the delicate root system
they have, but now I now better. Perhaps the sawdust drew up all the
nitrogen, I don't know.