Kies de juiste kweeklamp voor jouw kamerplant Deel 2 - Het LED Warenhuis

Choose the right grow light for your houseplant Part 2

Choose the right grow light for your houseplant Part 2

Part 1 of this article you can here find.

What is meant by the beam angle of an LED grow light?

You can best compare the beam angle of an LED Grow Light with the spray head of a garden hose. The way in which the spray head sprays the water droplets around is very similar to how an LED grow lamp distributes the light. When you open the spray head, the jet will become more powerful, but at the same time thinner. The surface that you can spray in 1 go is a lot smaller than when you close the spray head and the water comes out in tiny drops. Then a kind of mist is created that can spray a much larger surface, but it takes longer before the surface is completely wet.

With an LED Grow Light, we call that spread the beam angle. With LED Grow Lights you will usually find the beam angle in the specifications under the heading “beam angle” or “beam angle”. The most important thing you should know about this is that the amount of light particles that come out of a lamp is not influenced by the beam angle, but it does determine the amount of light particles that fall on a square meter.

The distance of your LED grow light above the plant

The light from your LED Grow Light spreads in a cone shape. When you hang the lamp higher, you will illuminate a larger surface. The amount of light particles that the lamp emits does not change, of course, but the amount of light particles per square meter will decrease.

With most LED grow lights, the specifications state how many light particles (within the PAR area) are emitted per square meter.


This is the most important term if you want to determine the power of an LED Grow Light. The wattage of the lamp and the distance between the lamp and the plant determine how many photons fall on the plant within the PAR area. The number of photons with a wavelength of 400 to 700 nanometers that fall on a square meter per second is called the “PPFD” value. This term stands for the “photosynthetic photon flux density”. This is expressed in the number of micromoles per square meter per second or µmol/m2/s.

Light color

More than 10 years ago there have been many experiments on the effect of a single light color on plant growth. This has shown that plants grow best under blue and/or red light. We now know that all other colors within 400 and 700 nanometers seem to contribute to the health of a plant. It is therefore important to choose light that has multiple colors of light instead of just red and blue. Since about a year there are more and more LED grow lights for sale with white light combined with red LEDs. This forms an extremely broad spectrum in which all colors within the PAR area are emitted in the correct ratio. Another big advantage of white light is that you can clearly see the natural colors of your plants and detect any problems with your plant at an early stage. This is a good choice if you are looking for a full spectrum LED grow light.

Apollo Falcon Spectrum
The spectrum of the Apollo Falcon, this is a WHITE Full Spectrum LED Grow Light.

The installation of your LED grow light

We have already talked about the distance between the LED grow light and the plant. The closer the lamp is to the plant, the more light the plant receives. It is also possible that the plant gets too much light and starts to “burn”. You can see this by discolorations in the leaf, when you notice this it is best to hang the lamp higher.

You can choose a larger, strong lamp or several smaller LED grow lights with which you can overlap the light. This choice mainly has to do with your growing situation, space and budget. With large plants, it is sometimes necessary to use several lamps, since you cannot fully illuminate the plant with 1 lamp. The idea is that you can provide the entire crown of the plant with light. When you hang several lamps close to each other, the light will overlap, in the places where the light overlaps you can add the ppfd values ​​of both lamps together.

Using an LED Grow Light

The amount of PAR light that falls on a plant in 24 hours is called the daylight integral, or DLI. This is measured in mol/m2/day. A mole is 1 million times larger than a micromole.

When a PPFD value is first multiplied by 3,600 and then divided by 1,000,000, you get the amount of light in moles that falls on the plant per hour. Suppose that 250 µmol/m2/s falls on the plant, then (250 * 3,600) / 1,000,000 = 0.9 mol/m2/per hour. If the LED grow light is on for 6 hours a day, the plant will receive 5.4 mol/m2/day.

Each plant has its own light needs, but in general seedlings need the least amount of light, around 10 mol/m2/day. Leafy vegetables slightly more, namely 17 mol/m2/day.

If you want to grow fruit/herbs/vegetables (no leaves) you need more than 25 mol/m2/day, then you should think of a lamp that can radiate about 700 to 800 µmol/m2/s.

Part 1 of this article you can here find

Our top-5 LED Grow Lights for 2020 you can here find.