How long until a plant nursery business starts making profit?

It depends heavily on the type. A vegetable seedling nursery can start generating cash within the first few seasons because the production cycle is short, weeks not years, so a well-run one can move toward profit relatively quickly once you have steady farmer buyers. Fruit and grafted sapling nurseries take much longer, often a year or more, before the first saleable plants are ready, so the profit comes later and you need working capital to survive the gap. Ornamental nurseries fall in between. Across all types, the first phase usually goes into building stock, reputation and a buyer base, and many nurseries reinvest early profits into expanding rather than taking income out. The honest point is to budget for a cash flow gap where money goes into plants, medium, pots and labour well before sales arrive, and to not over-borrow expecting quick returns. Start with fast-turnover lines to bring early cash, add slower high-value plants once established. Talk to a couple of running nurseries about their real timelines and keep enough working capital to cover at least the first year.