Just my opinion, but I'd much prefer checkboxes covering the numbers at maybe half point increments.
Or, we could follow NRCS's classification of soil pH?
Extremely acid..................3.5 – 4.4
Very strongly acid............4.5 – 5.0
Strongly acid....................5.1 – 5.5
Moderately acid...............5.6 – 6.0
Slightly acid......................6.1 – 6.5
Neutral...............................6.6 – 7.3
Slightly alkaline................7.4 – 7.8
Moderately alkaline..........7.9 – 8.4
Strongly alkaline...............8.5 – 9.0
I don't have any idea how widely accepted that classification system is, or if there is a better one somewhere else, but NRCS does probably employ more soil scientists than any other agency on the planet.
