7 misunderstandings about plant growth lights

- Mar 29, 2019-

7 misunderstandings about plant growth lights

Myth 1: Lumen = photosynthesis

Lumens is a suitable method to measure the number of indoor gardening myths at all times of light produced by plant growth lamps. Measuring light flow for photosynthesis is just plain stupidity. Let us be clear: Lumens (Scientific Symbol: LM) is a measure of how much light human perception is. It does not measure the light that drives photosynthesis in any way. period. Simply put, lumens measure the total amount of visible light from a particular source of light.

The evolution of the same light in plants and humans comes from the sun. But humans and plants use this light very differently. Humans use "in the visible range" between 400 nm and 700 nm, but our eyes are focused on 500-600 nm, and the spectrum is mostly green and yellow. Plants have a completely different reaction light, paying attention to their absorption around 400nm-500nm (blue) and 600nm-700nm (red). They also absorb some of the UV and IR bands in the visible spectrum as well as non-visible light.

Measuring the light output of lumen growth is an artifact of the lighting industry itself. Since the manufacturers of light bulbs are mainly focused on lighting for humans, they will publish lumens of light specifications. Some countries require bulbs to be rated for lumen output. Indoor gardeners have used this method to measure the brightness of their growing lamps, as it is generally available from the lamp manufacturer (at least until the indicator light comes to the site).

When it comes to courtyard lighting, it's time to stop thinking about it and start thinking about Light Quantum Flux Density (PPFD), which describes the density of photons reaching a particular area. The unit of PPFD is "micromolar (micromolar) per metre per second", which is a more useful measurement for plants in light than lumens. You need a quantum flux meter to measure the energy of photosynthetically active light that actually reaches your plant. When testing LED plant growth lights, be sure to pick a quantum flux meter designed for LEDs or your measurements will be turned off. Unfortunately, these devices are very expensive.

Myth 2: Summer and winter, all seasons

A respected garden writer recently wrote one of the most popular indoor gardening magazines: "In [the high-pressure sodium light is very red, and imitated the autumn sun to induce flowering." HID lamp sales staff and water shop owners also claimed that MH lamps are the best vegetative growth because they are "blue" like spring sunshine, while high pressure sodium lamps are the best flowers because they are like "red" falling lights.

This is the second most widely held horticultural misunderstanding: between the seasons of dramatic changes in the color of sunlight, this color shift induces flowering. Ask yourself: At noon, do you look at the blue in the spring or the autumn day?

The "color" of light is determined according to the ratio of Kelvin (K) to blue with a higher value and a lower red portion. This world looks very strange, if the temperature of the sun's light is anything, even close to the difference between the MH and HPS lights 2000-2500K from the season of seasons. Don't misunderstand: There is a seasonal shift in the color of daylight, due to the depth of the sun's light that passes through the atmosphere before reaching the Earth. However, this shift is small, 300-500K depending on where you live, which is a difference that is hard to detect human eyes.