What Gardenable Is
Gardenable is a hub of free planting tools for US home gardeners. Instead of generic advice keyed to a national average, every date it returns is computed against the NOAA frost record for the weather station nearest your ZIP code. The Succession Planting Scheduler builds a staggered sequence of sowings for an unbroken harvest; the Seed Starting Calculator counts back from your last frost to tell you when to start seeds indoors; What to Plant Now cross-references today's date against your local season; and the Frost Date & Hardiness Zone Finder reports the underlying numbers for any ZIP. It's for people who want their planting timed to where they actually live.
The Data Underneath
Frost dates — NOAA 1991–2020 Climate Normals
Frost dates come from NOAA's 1991–2020 Climate Normals, the most recent 30-year climatological baseline. For each weather station, dates are stored as a median (the 50/50 point) plus 10% and 90% probability bands, so the tools can report a typical date, an aggressive early date, and a conservative safe date. Each ZIP is mapped to its nearest station by latitude and longitude, so the frost dates you see reflect your location rather than a state or national figure.
Hardiness zones — USDA 2023 Plant Hardiness Zone Map
USDA hardiness zones are drawn from the 2023 Plant Hardiness Zone Map, which divides the country by average annual extreme minimum temperature. Each ZIP code is looked up against that map to return its zone, in the standard half-zone notation like "8b." Zones govern what survives the winter — useful mainly for perennials — and sit alongside the frost dates that govern when to plant annual vegetables.
Crop database — verified
The crop database draws its timing, spacing, and family data from a combination of sources — university extension publications, Johnny's Selected Seeds planting charts, and USDA references — and every entry records which sources back it. Entries may be drafted with the help of AI, but each one is checked against at least one published source before it is included, and the higher-traffic crops are cross-referenced across several. The source list on each entry is the verification discipline, not decoration.
How the Calculations Work
The dates aren't guesses or a proprietary formula. Each one is computed from two published inputs: your location's frost dates from NOAA's Climate Normals, and a crop's verified timing data — days to maturity, weeks before or after frost to sow. A tomato's transplant date, for example, is simply your last spring frost shifted by the number of weeks the crop's record calls for.
That matters because every date is traceable back to a named source rather than the output of a black box. Gardenable isn't a thin wrapper around someone else's service — the work is in assembling reliable frost data for every ZIP and verifying the crop timing behind it, then doing the arithmetic so you don't have to.
What It Isn't
Gardenable is not a community, a forum, or a shop. There are no accounts to create, no email list to join, and no behavioral tracking beyond standard analytics. It does not sell seeds, supplies, or memberships. It is a set of tools that take a ZIP and a crop and return dates — that is the entire scope.
Built By
Gardenable is built and maintained by a single independent developer — no venture funding, no team, no growth team. It is part of a small portfolio of focused tool sites. Questions, corrections, or suggestions are welcome at [email protected]; corrections to the crop data or frost figures are especially appreciated and are checked against the published sources before any change is made.
Sources and Methodology
- NOAA 1991–2020 Climate Normals — ncei.noaa.gov/products/land-based-station/us-climate-normals
- USDA Plant Hardiness Zone Map (2023) — planthardiness.ars.usda.gov
- Johnny's Selected Seeds planting charts — johnnyseeds.com
- University extension publications — UMN, Cornell, NC State, OSU, UC Davis