Begin with one named crop, one production system and one period. State whether you buy compost or make it, own or rent the building, and sell at the farm or deliver. Otherwise two cost-per-kilogram figures can describe entirely different businesses. Record the units behind each input: dry straw, wet substrate and delivered compost are not interchangeable quantities.
Separate investment from operating expenses. Building work and equipment create assets; substrate, power, packaging and routine labour support production. Include maintenance, owner labour and shared costs explicitly. For a profitability view, account for asset use and financing with a qualified adviser. For cash planning, record when the actual payments fall due. A capital purchase and its depreciation must not both be deducted as the same period's operating expense.