For decades, fluorescent lighting — particularly T8 and T5 lamps — has been the standard in research growth chambers, tissue culture rooms, and low-intensity plant growth environments. Their availability, low cost, and wide spectrum offerings made them a practical choice for university and commercial research labs.
In August 2023, the European Union began phasing out many fluorescent lamps under the RoHS Directive due to their mercury content. Mercury is a hazardous substance that poses risks to human health and the environment if released during use or disposal. The ban is part of the EU’s broader effort to reduce hazardous materials, improve energy efficiency, and accelerate the transition to mercury-free lighting technologies such as LEDs.
Beyond regulatory pressure, fluorescent lighting presents growing limitations in experimental repeatability, spectral stability, and operating efficiency — all critical factors for modern plant research.
This shift is now accelerating industry-wide interest in LED retrofits.
Limitations of Fluorescent Systems in Research
Despite their long-standing use, fluorescent systems introduce several scientific and operational challenges:
1. Low Electrical Efficiency
Only 20–25% of electrical energy becomes photosynthetically useful light. The remaining ~80% is emitted as heat, making temperature uniformity across growth shelves difficult to control.
2. Inconsistent Light Distribution
Fluorescent tubes emit light in all directions, which in some applications may require reflectors and careful positioning to avoid shadows and hotspots — factors that may affect experimental reproducibility.
3. Spectrum Drift Over Time
Spectral output changes as the tubes age, affecting:
• reproducibility across multi-year studies
• protocol transfer between facilities
• long-term phenotypic consistency
This often requires frequent lamp replacement — an interruption to research environments and budgets.
Furthermore, fluorescent is not a single spectrum necessarily. The variation in fluorescent spectra attainable is wide and the standardization that LED introduces improves the reliability of studies significantly. Not all LEDs are made equal, however. A spectrum of the same name might be different depending on the form factor it came in or year of its manufacture.
4. Fragility and Safety Concerns
Fluorescent tubes are prone to breakage and often contain mercury, requiring controlled disposal and adding handling risk.
A Modern Alternative: Research-Grade LED Retrofitting
LED systems provide a long-term solution that improves trait stability, experimental repeatability, and operational efficiency. A suitable retrofit replaces aging luminaires while ensuring continuity of spectral conditions — a critical requirement for ongoing research.
Valoya’s recommended LED replacement for fluorescent systems is the LLCV-Series, paired with spectra developed specifically for research-grade applications.
Key characteristics:
Parameter
Fluorescent Tubes
LED Retrofit (LLCV-Series)
Efficiency
~20% light / ~80% heat
~40% light / ~60% heat
Dimmability
Rare
Fully dimmable
Spectrum Stability
Decreases with age
Stable over lifetime
Heat Output
High radiant heat
Low radiant heat
Form Factor
Fixed
Modular, mix-and-match
IP Rating
< IP20
IP66 (humid-safe)
Table 1. Comparison of fluorescent tube key features against an LED alternative
In many cases, one LED bar replaces two legacy tubes while delivering more light using substantially less power. For example:
Replacing two 1200 mm fluorescent lamps with one LL120CV results in 35% more photons, 36% lower energy consumption, and more than double the photon efficacy.
Selecting the Appropriate Spectrum
One commonly used fluorescent baseline is the Cool White T8-840 spectrum, offering:
• 22% blue
• 40% green
• 33% red
• 4% far-red
While this spectrum supports general plant development, its red wavelengths do not sufficiently align with chlorophyll absorption peaks, limiting photosynthetic efficiency.
Valoya’s Lumi-CS spectrum was developed to closely mimic the usability of a standard fluorescent environment while increasing biological relevance and spectral precision.
Key improvements with Lumi-CS:
• Optimized red wavelengths matching chlorophyll peaks
• Added far red (~7%) to support flowering and improved biomass
• Higher CRI (94), supporting accurate visual assessment
• Stronger rooting and improved photosynthetic efficiency
Applications include:
• Standardized model plant research
• Tissue culture and micropropagation
• Low-to-moderate PPFD growth environments
For specialised studies (anthocyanin production, pathogen research, speed breeding, vernalization), alternative spectra such as NS12, AP67, or G2 may be more appropriate.
Case Example: Retrofitting at Selecta Klemm
Selecta Klemm (Germany) upgraded fluorescent lighting in tissue culture labs to a Valoya-based LED system to:
• improve spectrum consistency
• eliminate fluorescent lamp maintenance cycles
• reduce operating temperature in enclosed racks
The result was a future-proof lighting environment aligned with modern research demands and compliance regulations.
Summary
Fluorescent lighting systems have served the research sector well, but their limitations — compounded by regulatory phase-outs — now make retrofitting an urgent priority.
A successful transition requires attention to:
• Scientific continuity (replicating or improving baseline spectra)
• Photometric measurement and uniformity
• Integration with existing HVAC and control systems
• Spectral stability and long-term reproducibility
LED retrofitting offers tangible benefits: reduced power consumption, improved spectral performance, lower operating temperature, and significantly improved long-term research accuracy.
Next in the Series
In part two, we explore replacing high pressure sodium (HPS) systems, commonly used in greenhouses and high-intensity growth chambers — and the added complexities of managing radiant heat, spectrum imbalance, and light distribution during retrofit planning.
