COF Calculator

Sometimes it isn’t practical to get a soil test and build a custom fertilizer recipe using OrganiCalc. This is where a Complete Organic Fertilizer, or COF, can make a big difference.

This calculator makes it easy to build a COF using a variety of different inputs. It keeps track of your cost and calculates it on a per pound basis including extras like the cost of mixing, so you can quickly see which ingredients are driving the cost. Macronutrients which tend to be bulky are separate from the micronutrients so these may be mixed separately if you desire.

1. Enter your COF components and their listed nutrient content. Include the cost per pound and any notes (e.g. the supplier) if that is useful to you. It’s okay to enter amendments with no nutritive value, such as humates; they will be included in the recipe.
2. Enter your target lbs/acre for N, P2O5, K2O, Ca, Mg or S. The calculator will accommodate leaving targets for some of these blank.
3. Enter the area you want to amend, assuming a 6″ deep furrow slice.
4. Enter the estimated weight of each of the COF components and adjust the weights until the mix is balanced and meets the targets. There are hints as to which nutrients need to be increased or decreased to achieve balance.
5. You can adjust the overall amount on the recipe page. There is a place to enter a multiplier.
6. If you want a micronutrient recipe too, open the COF micronutrient calculator tab. Enter your target lbs/acre for micronutrients. If you want a filler such as compost, enter that too.
7. Email yourself a pdf of the completed recipe.