What kind of amendments do you add?
For slow release K? Cotton seed hulls
Fast release K? Wood ash
For the most part....When building soils. The K level in most is about right where I want it, without much direct amending for it......be careful with wood ash, as it's possible it can have things in it you don't want.....Use hard wood ash - I use Oak and Hard Maple.....Use only small amounts - Soil must be composted after being built - No short cut hot soils with layering.
I also use a K sulfate heavy tea for later bloom.
I like higher K levels then many nutrient lines have - some not by much, some more.
I like more K in bloom and K sulfate is the one for supplementing.
Adding K can help express natural coloring traits in plants.
The Ass Hat is correct in that too much K will make your plants have stunted budding. If your plant turns purple before or right at budding and at the budding points - too much/you went to far..In veg that's not hard as you don't want to hit bloom level use at all....just a nice uptick is good.
In bloom, after the stretch.....supplementing K with synthetic use begins when using synthetic nutrients. Last few weeks I've been known to use a 0-4-14 or a 0-6-18.....right at the start of each week...Sometimes a single shot of that 0-4-14 might happen at an earlier time.
I get what I want out of it.....works too. You can see that for yourselves...