This paper concerns virtue-based ethical principles that bear upon agricultural uses of technologies, such as GM crops and CRISPR crops. It does three things. First, it argues for a new type of virtue ethics approach to such cases. Typical virtue ethics principles are vague and unspecific. These are sometimes useful, but we show how to supplement them with more specific virtue ethics principles that are useful to people working in specific applied domains, where morally relevant domain-specific conditions recur. We do this while still fulfilling the need for principles and associated practical reasoning to flexibly respect variation between cases. Second, with our more detailed approach we criticize and improve upon a commonly discussed principle about ecosystemic external goods that are crucial for human flourishing. We show this principle is far more conservative than appreciated, as it would prohibit many technology uses that are uncontroversially acceptable. We then replace this principle with two more specific ones. One identifies specific conditions in which ecosystem considerations are against a technology use, the other identifies favorable conditions. Third, we uncover a humility-based principle that operates within an influential “hubris argument” against uses of several biotechnologies in agriculture. These arguments lack a substantive theory of the nature of humility. We clarify such a theory, and then use it to replace the uncovered humility-based principle with our own more specific one that shifts focus from past moral failings, to current epistemic limits when deciding whether to support new technologies.