Certified GKH Gardening Expert
Since two of the three of those crops produce their own nitrogen, it will only be necessary to add a bloom formula with no nitrogen at all. Raw potassium phosphate is fine, although, you will want to add trace minerals as well.
I usually don't recommend any particular brand or items, but in this case I will. Foxfarm makes a nutrient line of bloom boosters. You will only need one of these. It is called BeastieBloomz. This is a super concentrated phosphorous and potassium blend with no nitrogen.
You will want to use this at 1/4 strength that it recommends on the packaging. The results will speak for themselves.
Again, I usually wouldn't recommend this, but in your situation, you must be careful how you feed this arrangement, so I felt that the answer was warranted.