Equipment → Materials is your catalogue of consumables, seed, sand, loam, chemicals, etc., with cost and sell prices, supplier and codes.
Usage on jobs and spray records draws down stock automatically, and you get reorder alerts when stock runs low, so you're never caught short on site.
Import from Xero. If Xero is connected, Import from Xero on this page pulls your Xero tracked inventory items in as materials with cost and sell price (and the stock count the first time). Untracked items go to the Services price book instead. Safe to re-run: prices refresh, your live stock count is left alone. Once imported, the materials are ready to pick in the contract and project builders.
Price-book items on a project. The project builder's Materials step has one Add from Materials or price book… dropdown with two groups: Materials & stock and Price book. The price book is where QuickBooks and Sage imports land (and Xero's untracked items), so a product you keep in your accounts package — topsoil, skip hire, a day's digger — can go on the project as a priced charge line without re-typing it. A price-book line has no stock to deduct; a Materials & stock line still draws down stock as normal.