One of the reasons I stopped using tube feeders was it seemed that moisture
always collected and made the seeds moldy, regardless of how big a "roof" I
had over the feeder. While reading a garden magazine's "tips" section, one
reader wrote in with this idea, which I haven't tried but seemed like a very
good idea to me:

"No more moldy bird seed. Moisture used to collect in my finch feeder,
resulting in moldy seed at the bottom. I solved the problem by putting a
layer of gravel at the base where the moisture collects, almost up to the
level of the first feeding hole. This layer of gravel keeps the seeds away
from teh moisture and prevents them from getting moldy. - Betty Race,
Euclid, OH"

Excerpted from "Fine Gardening", Mar-Apr '99.

- Teresa Michelsen