For those that have been applying lots of fertilizer for clients, how do you track your expenses for tax purposes. I am contemplating just listing fertilizer under supplies on my tax return. Does that make sense? Just buying a whole lot of bags and using what amounts are required for each customer. I don't use GAAP accounting procedures. I use individual spreadsheets for all customers and track expenses on a spread sheet. For jobs such as mulching the mulch goes on the spreadsheet as materials reducing income. The reduced amount goes on tax forms at end of year. Income - materials I do this because i carry no inventory. Fertilizer and chemicals are so different because a purchase can cover many jobs.