top of page

MAXIMIZING GROWTH AND QUALITY WITH FULL-SPECTRUM HORTICULTURE LEDs: ACHIEVING OPTIMAL RESULTS IN VEG AND FLOWERING STAGES FOR INDOOR CULTIVATION

Oct 10, 2024

6 min read

0

0



To enhance the research post on the importance of spectrum and vertical farming in indoor cultivation, let's incorporate more detailed explanations, more precise definitions, supporting data, and visual emphasis on key points. Below is a revised and expanded version of the text:


Abstract:

Indoor cannabis cultivation heavily relies on full-spectrum LED lighting that mimics the sun’s quantum response area of the visible light spectrum (400-700 nm). This range is essential for photosynthesis, and achieving optimal rates of photosynthesis involves manipulating light intensity, carbon dioxide (CO2) levels, and temperature. During cannabis cultivation, both the propagation and flowering stages benefit from full-spectrum light, but each phase has specific light requirements. The propagation stage requires higher blue light, while the flowering phase benefits from more orange and red wavelengths. Additionally, green light plays a significant role in driving photosynthesis, particularly in the lower leaves of plants. Peak Roots offers highly engineered LED lights designed to support the different phases of the cannabis grow cycle. These lights enhance plant health and yield and optimize energy usage. For traditional larger cannabis plants, a Photosynthetic Photon Flux Density (PPFD) of 1,500 µmol m-2 s-1 at 25-30°C is optimal in the final weeks of flowering. In Sea of Green setups, smaller plants flourish under 1,100 µmol m-2 s-1 PPFD at 25-26°C during the last weeks of flowering.


Keywords:

Photosynthesis, Photosynthetically Active Radiation (PAR), Photosynthetic Photon Flux Density (PPFD), Spectrum, Indoor Horticulture, Quantum Response, PAR, Cannabis Sativa L.


Introduction

To cultivate cannabis successfully indoors, it’s crucial to understand the variables that contribute to photosynthesis and, ultimately, plant growth. The main factors driving photosynthesis include light, temperature, and CO2 concentrations. Light-emitting diodes (LEDs) have become a preferred lighting source for indoor horticulture due to their reduced heat output and customizable spectrum. These advantages make LEDs ideal for creating an optimal growing environment for cannabis.


How Photosynthesis Works

Photosynthesis converts light energy into chemical energy within the plant’s chloroplasts. Chloroplasts contain pigments, such as chlorophyll, which absorb light primarily in the blue and red spectrums. The Light-Dependent Reaction occurs in the thylakoid membranes of the chloroplast, where light energy is converted into ATP and NADPH. These molecules fuel the Calvin Cycle, which takes place in the stroma and synthesizes sugars, using CO2 as a reactant.


Understanding the different stages of photosynthesis and how light drives this process is crucial for maximizing cannabis yields. This is especially important in indoor environments where natural sunlight is unavailable, and growers rely on artificial lighting to replicate the sun's spectrum.




Full-Spectrum Light and Quantum Response

The visible light spectrum includes wavelengths between 400-700 nm, known as Photosynthetically Active Radiation (PAR). Plants primarily absorb blue and red wavelengths, which are critical for photosynthesis. However, green light, often overlooked, penetrates deeper into the plant canopy, driving photosynthesis in lower leaves. Full-spectrum lighting covers the entire PAR range and ensures plants receive a balanced light diet throughout their growth cycle.


Peak Roots' full-spectrum LEDs are engineered to replicate this quantum response area, delivering precisely tuned light during both the propagation and flowering phases. These lights include two essential spectra:


  • ICE Spectrum (Vegetation/Propagation): Full Spectrum that is rich in blue light for optimal early-stage growth.

  • GOLD Spectrum (Flowering): Full Spectrum that is rich in orange and red wavelengths for robust flowering.

  • SUNLIGHT Spectrum (Flowering/Veg): Full Spectrum and Red + Far red)





Light Intensity: PPFD and DLI

Two important metrics to consider in indoor cultivation are Photosynthetic Photon Flux Density (PPFD) and Daily Light Integral (DLI):

  • PPFD measures the number of photons that reach a plant per square meter per second (µmol m⁻² s⁻¹).

  • DLI quantifies the total amount of PAR light delivered to plants over 24 hours, measured in moles per day (mol m⁻² d⁻¹).


Ensuring even light distribution across a growing area is critical. Uneven lighting can lead to inconsistent plant growth, wasted energy, and reduced yields. Proper PPFD measurements are essential to balance energy efficiency and plant health.





Cannabis Growth Phases and Light Requirements

Cannabis cultivation has two primary stages: Propagation (Cloning/Veg) and Flowering. Both phases require specific light intensities and spectrums to achieve optimal growth.

Growth Phase

PPFD (µmol m⁻² s⁻¹)

Optimal Temperature

Key Wavelengths

Propagation

30-50 (Cloning)

18-24°C

Blue light (400-500 nm)

Flowering

1,100-1,500

25-30°C

Red/Orange light (600-700 nm)

  • Propagation: During this phase, higher levels of blue light promote root development, strong stems, and dense foliage. Peak Roots recommends maintaining a PPFD of 30-50 µmol m⁻² s⁻¹ for cloning and 265-280 µmol m⁻² s⁻¹ during early vegetation.

  • Flowering: As cannabis transitions into the flowering stage, orange and red wavelengths become more critical for bud development and increased biomass. A PPFD of 1,100-1,500 µmol m⁻² s⁻¹ is ideal depending on the plant size and density.


The Benefits of Full-Spectrum LEDs

Using full-spectrum LEDs provides several advantages over traditional lighting systems:

Benefit

Description