How to Use the Compost Calculator
All materials that you are likely to put into your compost pile have some nitrogen and some carbon in them. For your compost to heat up properly and produce high quality compost it must have the proper ratio of the two. For best results you want to have 25 to 35 units of carbon for every unit of nitrogen in your mix. The Compost Calculator allows you to determine what this ratio is, given your particular mix of materials.
Units: To start, choose your units and click the "Use these Units" button. For the most accurate results, choose pounds or kilograms then weigh all of your ingredients. The calculations are based upon C/N ratios using weights, but there is a great deal of variability in those ratios and the range of acceptable ratios in your completed pile is quite wide. As a result, you can avoid weighing everything, or anything, by using a volume measure. Whether your measure is pounds or wheel-barrow-loads, the calculated C/N ratio will be the same.
Materials: For each of the materials you will be using, enter the quantities you are planning to put into your compost pile. We have included a long list of possible ingredients. If you can't find an exact match, choose something close. For example, dried grass clippings have about the same effect as "Grass (hay, dry)." If you don't want to sort out your fruit waste from your vegetable waste, just use "Kitchen waste."
Calculate: When you have entered the quantities for all of your ingredients, click the "Calculate" button. The calculator will display the carbon/nitrogen ratio and provide you with suggestions if your ratio is outside the recommended range.
Water: Now that you know how much of what it will take, you can build your pile. For your pile to compost properly, it must also have the proper water content all through the composting process. We can't calculate that amount for you, but it's easy for you to check. Just add water until you can tightly squeeze a handfull of the material and a drop of water barely escapes from the material. If you have water dripping out, it's too wet. If the material in your hand won't even stick together - it's too dry. Add water if it's too dry. Add dry ingredients if it's too wet. If you get a strong smell of ammonia after you start composting, the pile is probably too wet. Mix in some sawdust or other dry material to make the smell go away.
Air: The final ingredient for proper composting is air. You must have air throughout your pile for it to compost properly. That means you will need to turn your compost regularly - daily if you can. This provides the air that the micro-organisms need to digest your materials and make your ideal compost. Be sure to check your water content when you turn your pile - adjust accordingly.
Volume: It's not an ingredient, but it's an import part of proper composting. You must have a large enough compost pile to hold the heat generated by the working micro-organisms for several days. This heat of composting can then kill weed seeds, diseases and bugs that might otherwise damage your plants when you use the compost.
Too complicated? The Compost Calculator is for those that want to dig into the details. If you want to keep it simple, just use one part of fresh green material (like fresh grass clippings or kitchen waste) to four parts of dead brown material (like dry leaves). If your pile doesn't heat up in a day or so, add some manure or blood meal.
The Compost Calculator takes the quantity of each material that you provide and calculates the carbon/nitrogen ratio of the resulting combination. Give me more details.