Root & Photon explains indoor-growing decisions using evidence that matches the claim. A source-based guide is not presented as a hands-on product test, and material limitations remain visible.
Evidence levels
- Source-based explanation: official documentation, standards organizations, university extension material, and other qualified public sources support the page. This is the current evidence level used by our published guide.
- Comparative analysis: products or approaches are compared against a declared buyer question, consistent criteria, current source snapshots, and visible unknowns. A comparison is not a product test.
- Hands-on testing: this label is used only when a page records the equipment, setup, date, method, observations, and limitations of work actually performed.
How we build a page
- Define the buyer question, intended reader, use case, and important exclusions.
- Qualify sources for the exact claim they are being used to support.
- Separate sourced facts, calculations, editorial interpretation, and unresolved questions.
- Use language no stronger than the available evidence and state important limitations.
- Check structure, links, labels, authorship, responsive presentation, and publication metadata before release.
Review and comparison boundaries
No product review is currently live. A future review or comparison must identify the product set and market, distinguish specifications from observations, date volatile details such as price and availability, and avoid universal winner language when the evidence supports only conditional trade-offs.
Corrections and updates
When evidence, specifications, availability, or guidance changes materially, we review the affected claim and update, qualify, or remove it. Meaningful changes receive a visible date. See the Editorial Policy for the broader correction standard.
Current public scope
The current public article is an E2 source-based explainer: PAR, PPF, PPFD, PPE and DLI: What Each Grow-Light Metric Means. It does not claim Root & Photon performed a fixture test or crop trial.
Last reviewed: July 25, 2026