Transition to Horticultural Lighting V4.0

The DLC will begin accepting applications under Horticultural Technical Requirements V4.0 on April 18, 2025. All products must be included in update applications to update products to V4.0 by October 31, 2025, or will be delisted. Products will not be automatically updated.

The deadline to submit applications to qualify products under V3.0 is April 17, 2025.

Timing for Horticultural Technical Requirements V3.0 – V4.0

Updating Products to Hort V4.0

If you will be submitting new products under V4.0 or updating existing products from V3.0 to V4.0, please review the timeline above and information below before preparing your application(s).

• If listed products have not changed since original qualification, update applications will need to be submitted to confirm product performance and market availability. Specific instructions will be available shortly.

• If listed products have changed since original qualification, update applications must also include other test reports or documentation related to the specifics of the product change and impact on demonstrating compliance with the technical requirements.

New Application Forms

New application Excel forms will be required for all Hort V4.0 applications (including update applications). You will be able to download copies of these Excel forms below and on each Qualify a Fixture page prior to April 18, 2025.

Application Fees

Certain application fee items will be increased for Hort V4.0 applications starting on April 18, 2025. This increase allows the DLC to maintain the rigorous level of evaluation and review that goes into each application and supports new QPL features that provide better information for end users. Please see Application Fees page for details.

Applications to update products to V4.0 where the listed products have not changed since original qualification will be charged a $500 Non performance-affecting updates fee (per family).

Applications to update products to V4.0 where the listed products have changed since original qualification will be charged dependent on the type of update(s) being made to the product, as described on the application fees page.

Photosynthetic Photon Efficacy (PPE) Threshold Increase

Hort V4.0 increases the PPE threshold to a minimum of 2.5 μmol × J^-1, which is an 8.7% increase over the Hort V3.0 PPE threshold. This increase will set the DLC efficacy threshold for LED-based horticultural lighting at more than 45% above the most efficacious non-LED option, the 1000W double-ended high pressure sodium luminaire. This increase will cause the least efficacious V3 listed products (~11% of the QPL) to be delisted.  

Removal of lamp categories

In 2021, Hort V2.1 introduced several new product qualification pathways for DC-powered products, liquid cooled products, and several lamp types. Since then, all new categories have seen participation and QPL listings have been actively growing, except for lamps. With the lack of uptake around lamps and no comments received on the draft proposal to maintain lamp eligibility, Hort V4.0 removes the qualification pathway for lamps.

Clarifications to Various Requirements

To improve the clarity of the Horticultural Technical Requirements, a variety of updates have been made throughout the document. For example, clarifications to what the DLC considers “nominally distinct wavelength band” have been included in the LM-80 applicability section, language has been added to clarify testing requirements for spectrally tunable products based on their spectral tunability and to better define what the PPE-tested qualifying state should be, and other clarifications have been made to various requirement details.

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