The minimum amount of light required to grow plants with grow lights can vary depending on the specific type of plant and its growth stage. Generally, plants use light for photosynthesis, which is crucial for their growth and development. Here are some key
Light Intensity:
This refers to the brightness of the light. It’s usually measured in foot-candles or, more commonly, in micromoles per square meter per second (µmol/m²/s) when referring to grow lights. Most leafy greens require a light intensity of about 200-400 µmol/m²/s, while fruiting plants like tomatoes or peppers might need over 600 µmol/m²/s.
Low Light Intensity: 200 – 400 µmol/m²/ For plants with minimal light requirements, such as many leafy greens, a light intensity ranging from 200 to 400 µmol/m²/s is adequate. This level supports basic photosynthesis processes and is suitable for indoor environments or shaded areas.
Medium Light Intensity: 400 – 600 µmol/m²/sThis category is a transitional phase, often ranging between 400 µmol/m²/s and 600 µmol/m²/s. It’s suitable for plants that require a bit more energy than leafy greens but less than high-light-requiring plants. This intensity supports steady growth and is ideal for a broader range of indoor plants.
High Light Intensity:> 600 µmol/m²/s Fruiting plants, such as tomatoes or peppers, thrive under high light intensity, typically requiring over 600 µmol/m²/s. This level ensures optimal growth, fruit development, and overall plant health, particularly for plants that are naturally exposed to direct sunlight for most of the day.
Daily Light Integral (DLI):6– 13 hours/per day
This is a measure of the total amount of light delivered in a day. It’s measured in moles of light per square meter per day (mol/m²/day). Different plants have different DLI requirements. Low light plants (like some ferns) can survive with a DLI of 5-10 mol/m²/day. Most vegetables and flowering plants need at least 20-30 mol/m²/day.
Light Quality:
Light quality refers to the color or wavelength of light. Plants generally use blue and red light most efficiently. Blue light promotes vegetative leaf growth, while red light contributes to flowering and fruiting.
Photo-period:
Photo-period is the duration of light exposure in a 24-hour period. Some plants require long days to flower, while others require short days. However, for most leafy greens and herbs, a photo-period of 16-18 hours is sufficient.
Plant Growth Stage:
Seedlings require less intense light. As plants grow and enter the vegetative and flowering stages, their light needs typically increase.
It’s important to select a grow light that can meet the specific light requirements of your plants at each stage of their growth. It’s also beneficial to use a light meter to measure the actual light intensity at plant level, as it can be influenced by the distance of the light source, the type of light, and any obstructions or reflections.
These principles are based on research and guidelines from various sources including:
Leave a Reply