Kevin, bananas are heavy feeders that like lots of water, warmth and sunlight. If you want to keep them growing slowly but staying healthy, a light feed with a balanced fert every few weeks through the winter, then ramping up as warm weather gets going next spring would be good.
Balanced fertilizer is one with a formula where the three major nutrient numbers are similar or the same. eg. I have some that is 7 - 7 - 7 that I use for my Earth Boxes to grow veggies. I think if you look at the package of your tomato feed, you'll find it has the middle number (phosphorus) higher than the other two. Potassium is the third number, so as long as the fertilizer you use has all three numbers fairly equal, your plant will be getting a good dose of potassium and it's not necessary to add any potash.