I would rethink your soil-planting-potting scheme next time you plant. I think a common mistake is making sure that your soil has good draining qualities to it. If you just use straight super soil, or whatever you use (I am in the west, so super soil is the way to go here), mix a little pumice in there to add some structure to the soil. In this way, you will make sure that the entire profile (imagine cutting your pot in half and looking at the soil in the pot from the cut side) is draining well. I know some friends who have the same problem. Also, the more structure you have, i.e. add some vermiculite, pumice, or pearlite to your usuall soil mix, the better the soil will be able to buffer itself, the better the nutrient holding capacity of the soil, and the better the draining. Not only that, but your roots will be happy!! Hope this helps a little bit, and I am no expert, but I am an applied plant ecologist and biologist and taking a class on soils, so I know a lot about plants!

Peace