Research standard
How we research
Sprout Authority publishes two kinds of evidence: cited growing guidance and researched product decisions. Structured planting numbers begin with a named source, and every recommendation separates our editorial judgment from retailer data. Article source trails link to the original publishers so readers can inspect the evidence directly.
Growing guidance and plant data
University extension publications are the preferred source for planting timing, spacing, water, soil, and problem guidance. USDA data supplies 2023 hardiness zones by ZIP. NOAA 1991-2020 climate normals supply frost anchors. A source must name the fact it supports, provide a stable URL, and record when it was checked before it enters the structured plant store.
Planting windows are stored as weeks relative to the local frost anchor when the source supports that conversion. Season-based guidance stays season-based. Missing values remain missing. The same structured field renders in plant profiles, tools, and generated zone pages.
The transformed NOAA frost-date dataset publishes the ZIP-to-station assignments used by the tools, along with versioned source files, mapping limits, a checksum, and a downloadable CSV. This keeps the calculation inspectable without presenting a station normal as an address-level forecast.
Editorial source trails
Growing articles inherit relevant citations from the plant records they use. Problem guides cite original extension or institutional guidance for identification and management. Buying guides pair horticultural guidance with official manufacturer documentation for product facts. Each source trail shows the publisher, original title, check date, and the scope it supports. Sources support the factual foundation; the article's organization and recommendations are Sprout Authority's editorial work.
Garden gear and the Sprout Score
Every recommended product carries a Sprout Score from 0 to 10. This is an editorial research score. We cross-check manufacturer specifications, owner reviews across retailers, and relevant horticulture guidance, then score four dimensions.
Fit for purpose
30%How well it does the specific garden job people buy it for, the use-case fit that matters most for this category.
Owner sentiment
25%Aggregated owner feedback from retailer reviews (recency-weighted), garden forums, and horticulture publications.
Build quality
25%Materials, construction, weather and UV resistance, warranty terms, and long-term failure patterns from multi-season owners.
Value
20%Price vs. category peers at equivalent quality, plus "worth it at this price" sentiment.
The composite is computed from those four weighted scores, never typed in by hand, and a build check fails if any stored score drifts from its breakdown. Retailer availability can change after publication, so direct listings are checked separately and unavailable buttons are suppressed. Search fallbacks are labeled as searches.
Updates and corrections
A publication date moves only when the article or its evidence changes. Plant records preserve their source check dates, and material updates refresh the affected record, article date, and public source trail together. Automated audits fail the build when citations disappear, structured scores drift, or purchase routes become dishonest.
We are reader-supported: buying through our links may earn a commission at no extra cost to you. It never changes a score or a ranking.