If you’re asking what color light would be the best for growing plants in a polytunnel, the answer is blue and red. However, it’s worth emphasising that plants will grow well with most colours of lights, and the amount of each colour will be the deciding factor. Blue and red are the best colour light for growing in the polytunnel because they are close to plants’ spectra.
Additionally, plants can also use some green and yellow. The gardener in the UK needs to ensure the proper colour of grow light in the polytunnel beside the other conditions like temperatures. After all, the control you have on the polytunnel conditions is its primary advantage, regardless of location and weather.
How To Choose What Color Light Would Be The Best For Growing Plants In A Polytunnel
When choosing a colour of grow light, it’s a common mistake to choose green, yellow, and orange because we’re assuming they are similar to the spectrum given by the sun. After all, we’re mimicking the conditions that plants require for growth, right? However, studies show that the photosynthetic activity of plants is in the blue and red frequencies.
For growing plants in the polytunnel, it will be best to use red and blue lights because they take in maximum chlorophyll as a response in these colours. However, you must understand that there are different types of lights and colours that you can use in the polytunnel. While blue and red are the best colours for growing plants, a full spectrum LED grow light will be ideal for the polytunnel.
Fluorescent lights vs LED lights
If you use a fluorescent bulb that emits blue lights, this will help to get bushy plants. Fluorescent bulbs are also excellent when seeding because they don’t give off too much heat. It’s worth noting that when choosing a fluorescent lamp, you may choose between cool white and warm white, where the former has more blue.
On the contrary, the more energy-efficient and long-lasting LED lights use wavelengths. The use of wavelengths makes it easier for you to choose the actual colour spectrum instead of fluorescent bulbs. Keeping this in mind, the following information will discuss each colour and its effects on plants.
Before you use blue light, the emphasis is necessary on mixing it with other spectra of lamps. This colour affects the leaf thickness and colour, energy acceptance, and chlorophyll content, but some plant species can experience stunts in growth from this colour. A minimum intensity of blue light is enough to help with growth and maturity rate and minimise plants’ water loss.
Another influential colour of light for growing plants in a polytunnel is red. This spectrum is best to combine with blue if you genuinely want to achieve well-developed plants. The best combination with blue light is because this wavelength plays a role ingerminatingf seeds, flowering, and expansion of leaves and stems.
Among the spectrum of colours, the UK gardeners usually ignore the green light because it has the least efficiency. But according to Michigan State University, it is still valuable for photosynthesis and plant structure. A green light is also helpful for the polytunnel with thick top canopies so that the lower canopy leaves still receive light.
What Is DLI?
When looking for the colour of grow lights, you might encounter the term DLI. This term gives you an idea of how much light will be available to the plant for photosynthesis. Therefore, more DLI means more photosynthesis, which equals better growth.
In polytunnels, adding grow lights to increase the DLI will help produce quality plants. The rate of growth will depend on the productivity of the plants. However, you must also know the proper distance between the plants and your light.
Remember that you might use fluorescent, LED, or high-intensity discharge lights depending on your polytunnel operation. If you’re using LED lights, maintain a distance of up to 30 inches above your plants. On the contrary, fluorescent lights can have 6 inches above the plants, while high-intensity discharge lights can be 8 feet above the plants.
Is Light Intensity Important For Growing Plants In A Polytunnel?
After learning the colour spectra, the next step is to realise the importance of light intensity in the polytunnel. In general, the higher the intensity, the higher the rate of photosynthesis will be as well. As discussed previously, the addition of grow lights is vital because polytunnel glazing decreases the light available for photosynthesis.
Maintaining optimum conditions in the polytunnel can be challenging. Besides the proper temperatures, do you know what color light would be the best for growing plants in a greenhouse? The direct answer would be a combination of blue and red lights because these colours are the most significant for plant growth.
Studies have shown that these colours are close to the spectra that plants use. But while these are the best colours, a full range LED grow light will be the most beneficial for your plants. Each colour has a role in the plant’s health, so learn the amount your plants will need for each colour instead.