Whether you are planting a few containers on a balcony or planning a commercial growing operation, the right resources depend heavily on scale. This roundup separates home-gardening material from commercial and larger-scale urban farming resources, since advice aimed at one rarely transfers cleanly to the other.
For home gardeners
At home-garden scale, the most useful resources are usually free or low-cost: your local state university extension office (most U.S. states have one, and most publish region-specific planting calendars and pest guides), your city's parks or sustainability department if it runs a community garden program, and seed-starting guides matched to your USDA hardiness zone rather than a generic national guide.
Check that any guide you use matches USDA's current zone map rather than an older one: USDA's Agricultural Research Service released an updated Plant Hardiness Zone Map on November 15, 2023, its first revision since 2012, built from 13,412 weather stations compared to the roughly 8,000 used previously. According to coverage of the release, about half the country shifted into the next warmer half-zone as a result, so a planting calendar written before 2023 may list a zone that no longer matches your location. The current map is at planthardiness.ars.usda.gov.
For commercial and larger-scale operations
At commercial scale, resources shift toward business planning and regulatory compliance: USDA's Office of Urban Agriculture and Innovative Production for grant programs (see urban farm funding), your city's zoning code for what is actually permitted where you plan to grow, and food-safety certification requirements if you intend to sell produce, which vary by state and by sales channel (farmers market vs. wholesale vs. restaurant supply).
Wholesale buyers in particular often require a food-safety audit before they will list a grower. USDA's Agricultural Marketing Service runs the Harmonized GAP (Good Agricultural Practices) audit program, developed through an industry-led harmonization effort to cover pre- and post-harvest produce handling with a single audit checklist rather than several overlapping ones. A 2018 joint USDA-FDA announcement confirmed that the technical requirements of the FDA's Produce Safety Rule overlap with what the Harmonized GAP audit already checks, so a grower passing that audit is also addressing several FDA requirements at the same time. Audit costs and any available cost-share funding change over time and have historically varied by state, so check USDA AMS's own Harmonized GAP page for current fees before budgeting for one.
Matching resources to your actual scale
A common mistake is researching at the wrong scale - reading commercial farm-business planning guides for a backyard garden, or relying on home-gardening tips for a project that needs real zoning and food-safety compliance. Before diving into resources, it helps to write down, in one sentence, what you are actually planning: a home garden for your own household, a shared community space, or a farm intended to sell produce. That one sentence determines which half of this list actually applies to you.
Where to go next
For a step-by-step planning process rather than a resource list, see how to start an urban farm (commercial/larger scale) or how to start a community garden (shared, resident-run space).