Make sure to evenly space your violets before you plant them in the pots. Proper placement helps prevent the spread of the disease and aids in the early detection of the problem.
There is no definitive measurement for the distance between the indoor violets. However, make sure that each plant should not touch the one adjacent to it.
To further prevent crowding in pots, remove any new growth that you see emerging along the stems. Another alternative is to let them grow a little, then cut them off in preparation for propagation.