Since I started making my own laundry detergent, I’ve had boxes of borax and washing soda sitting around. When we ran out of dishwasher detergent, I presumed that a homemade version could be made with what I had on hand. It definitely saved our budget, and the dishes have been clean ever since.
(I have also heard that some people are adding citric acid powder, but I haven’t tried it.)
*UPDATE*: When I posted this recipe, I did not make any claims of being “natural;” it was merely an affordable choice during a financially-challenging season. Since then, we have moved, and no longer have a dishwasher, so I am unable to test further options. If you have suggestions for other readers, feel to leave them in the comments!