The growth and development of Dragon fruit /pitaya (belonging to the cactus family) have specific requirements for the spectrum, and the requirements for light quality (spectrum) vary at different growth stages. The following are recommendations for spectrum selection for pitaya growth, combined with its physiological characteristics and actual research:
1. Core principles of spectrum requirements
Pitaya /Dragon fruit is a light-loving plant and usually requires sufficient sunlight (full spectrum) under natural light. However, when artificially supplemented with light (such as greenhouse or indoor planting), it is necessary to optimize growth by adjusting the ratio of red and blue light and supplementing the spectrum of specific bands , so grow led light is necessary
2. Spectral requirements at different growth stages
(1) Seedling stage (vegetative growth period)
Requirements: Promote root development, leaf growth and stem strength.
Recommended spectrum:
Blue light (400-500 nm): accounts for about 30%-40%, promotes chlorophyll synthesis and cell differentiation.
Red light (600-700 nm): accounts for about 60%-70%, provides energy to support stem elongation.
Photoperiod: 12-14 hours/day, simulating natural long days.
(2) Flowering and fruiting period
Requirements: Induce flower bud differentiation, promote flowering and fruit enlargement.
Recommended spectrum:
Red light (660 nm): 70%-80%, red light (especially far-red light) promotes the activation of flowering hormones (such as phytochrome).
Blue light (450 nm): 20%-30%, maintains photosynthesis and prevents excessive growth.
Supplement far-red light (700-750 nm): A small amount (about 5%-10%) can increase the flowering rate.
Photoperiod: Appropriately shortened to 10-12 hours/day, simulating natural short days to stimulate flowering (some varieties require long days, which need to be adjusted according to the variety).
3. Auxiliary effects of other spectra
Ultraviolet light (UV-A, 315-400 nm): A small amount of ultraviolet light can enhance the skin color of pitaya (such as the accumulation of red pigments in red-skinned varieties) and stress resistance, but avoid excessive amounts (may burn tissue).
Green light (500-600 nm): Although the utilization rate is low, it can penetrate the canopy to improve the photosynthetic efficiency of the lower leaves. It is recommended to supplement it in small amounts (about 10%).
4. Practical application suggestions
Commercial planting: Use a red and blue LED combination lamp (red light: blue light ≈ 3:1 to 5:1), combined with full-spectrum white light LED supplementary lighting.
Home planting: Directly choose a full-spectrum plant growth lamp (400-700 nm) to simulate natural light.
Light intensity requirements: The light intensity is recommended to be 200-400 μmol/(m²·s) to avoid burns caused by direct strong light.
5. Notes
Photoperiod regulation: Pitaya/Dragon fruit is a short-day or day-neutral plant (different varieties have differences), and the lighting time needs to be adjusted according to the variety.
Temperature coordination: The light quality effect is affected by temperature. It is recommended to be 25-35℃ during the day and 18-25℃ at night.
Lighting period: Lighting for 4-6 hours after sunset can significantly promote growth, especially in winter.
6. Research support
Experiments show that the combination of red and blue light (660 nm + 450 nm) can advance the flowering time of pitaya by 10-15 days and increase the sugar content of the fruit. For example, when red light accounts for 70%, the weight of a single fruit increases by about 20% (Source: Research data from the Chinese Academy of Agricultural Sciences).
The best spectrum solution for pitaya:
Seedling stage: 40% blue light + 60% red light
Flowering and fruiting stage: 70%-80% red light + 20%-30% blue light (with a small amount of far-red light as auxiliary)
Filling light equipment: Choose LED plant growth lights with adjustable spectrum to flexibly adapt to the needs of different stages. you can find dragon fruit grow led light on https://www.benweilight.com/professional-lighting/led-grow-light/dragon-fruit-growth-full-spectrum-led-bulb.html
