Ok. What you need first of all is a soil test. The components of the tank mix change based on calcium/magnesium requirements and soil pH. Otherwise, to answer your question about potassium, anyone used to spreading high urea granules is in for sticker shock when they start pricing potassium. I use potassium nitrate as my K source. 13-0-45. Runs around $50 a bag here. But it will cover 1-2 acres depending on the rate it is applied at. I also add a chelated micronutrient mix sold as FEature 6-0-0 from Loveland Products. This is very important because the nice green color that I get from spraying my fertilizers is not from putting down 1 lb of N. It is from the potassium helping with water management and root growth, along with more than adequate levels of micronutrients.
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