Natural cleaning products problem

I've made a dishwashing machine powder from 50/50 borax/bicarb (baking soda).

I'm sad to say that it is doing a very poor job of getting my dishes clean. It seems I almost have to wash them completely beforehand to get them to come out clean in the dishwasher, which is obviously rather silly.

Anything else I can add to the mixture to get it working better? Or will I have to go back to using supermarket "green" powders?