SOURCES AND VERIFICATION
How SeedsByZone researches and verifies listings
Our directory is built from seed sellers' own published information. Climate specializations, ordering methods, and zone assignments must have supporting sources.
Our basic rule: verify, don't assume
SeedsByZone organizes regional seed sellers by their published climate specializations and ordering models. We do not assign attributes simply because they seem likely based on a business's location, name, or catalog appearance.
Every published seller record must have an identifiable source and a checked date. Information that cannot be supported by the seller's published material is not presented as a verified fact.
An attribute that is not stated remains unstated. We do not turn missing information into a positive or negative claim.
SOURCE POLICY
Where seller information comes from
Primary sources: sellers themselves
Seller information is rebuilt from the seller's own published website, including its About pages, seed catalogs, product information, and other relevant published descriptions.
These sources are used to verify:
- Seller name and business location.
- Published climate and regional specializations.
- USDA hardiness zones supported by the seller's information.
- Published ordering methods.
- Catalog focus and seed categories.
- Official website and supporting source links.
Secondary discovery sources
Extension and university supplier lists may be used to discover potential seller names.
These lists are discovery sources only. Their descriptions, classifications, and other attributes are not copied into SeedsByZone seller records.
Every field published in a seller record must be rebuilt and supported using the seller's own published information.
Sources we do not treat as verification
A business address, search result snippet, photograph, customer comment, or third-party directory description does not independently establish a seller's climate specialization or ordering model.
We do not infer seller attributes from information that the seller has not published.
RECORD VERIFICATION
What we verify for each seller
1. Seller identity and location
We record the seller's published name and base city and state. A base location identifies the business; it does not establish the climates or zones for which its seeds are intended.
2. Climate specializations
Climate specializations are recorded using the seller's own descriptions. We preserve the meaning and framing of those descriptions rather than rewriting them into unsupported suitability claims.
3. USDA zone focus
A seller is assigned to a USDA zone only when its published material supports that assignment. A seller's base-state location is never sufficient evidence of zone specialization.
4. Ordering model
We record one of the following ordering models when supported by published information:
- Online small-packet: online ordering of small seed packets.
- Catalog mail-order: ordering through a published catalog mail-order process.
- Both: both ordering methods are supported by the seller's published information.
If the published information does not establish an ordering model, it is not upgraded through assumption.
5. Catalog focus flags
Categories such as heirloom, native/wildflower, vegetable, flower, and dryland are recorded only when supported by the seller's own published descriptions.
A category is not assigned simply because a seller offers an individual product that might fit it.
ZONE REFERENCE
USDA hardiness-zone data
The zone lookup uses a locally bundled ZIP to USDA zone reference table, running client-side with no external ZIP lookup API. The table was built on 2026-10-31 from the 2023 USDA Plant Hardiness Zone ZIP listing published by the PRISM Climate Group (39,928 ZIP codes); half zones are grouped to whole zones.
The zone reference is based on the USDA Plant Hardiness Zone Map.
USDA hardiness zones describe average annual extreme minimum winter temperatures. They do not describe every aspect of a location's growing climate.
A ZIP-code lookup is a general reference, not a property-level climate assessment. Local elevation, exposure, soil, summer heat, rainfall, and other conditions can affect growing results.
Most importantly, the ZIP lookup does not assign sellers to zones. Seller-to-zone matching is derived separately from the seller's own published information.
RECORD MAINTENANCE
Checked dates and information updates
Every published seller record includes a checked date identifying when its supporting information was reviewed. The date applies to the information examined at that time; it does not guarantee that the seller's website or catalog has remained unchanged afterward.
Seller websites, catalogs, product offerings, and ordering arrangements can change. Visitors should consult the original source before relying on information for a purchasing decision.
How updates are handled
When updated seller information is identified, the relevant source is reviewed and the affected record can be corrected. Updated information receives an appropriate checked date.
We do not treat an old checked date as evidence that information is still current.
Reporting incorrect information
Visitors and sellers can report outdated or inaccurate information using the form below or through the contact page. Include the seller name, affected information, and a link to the supporting published source.
Corrections are reviewed before directory records are changed. Submitting a correction does not automatically publish an update.
Report a correction
Or report it via the contact page →Limitations of the directory
SeedsByZone is a research directory, not a complete inventory of every seed seller in the United States. A seller's absence does not mean that it lacks regional expertise or relevant products.
Listings reflect information that could be supported by the seller's published materials. Sellers with limited online information may not have enough verifiable information for inclusion.
Climate descriptions and USDA zone references should be treated as research aids rather than guarantees of plant suitability, germination, survival, or yield.
We do not independently test seeds, conduct germination trials, or certify seller claims. Our role is to organize and attribute the information sellers publish.
Questions about our methodology
If you have questions about a source, a seller's classification, or a particular record, contact SeedsByZone with the relevant listing and supporting information.
Contact SeedsByZone