Horticultural bulbs for green plants

To choose the ideal LED grow light, I advise you to first consider the specific light needs of your plants, their growth stage (vegetative or flowering), as well as the area to be illuminated. I also look at the power and light spectrum of the lamp. I explain these criteria in more detail in our buying guide.

In practice, the necessary LED power depends directly on the growing area and the light intensity required by your plants. For a small area, such as a windowsill or a 60x60 cm shelf, a 50 to 100W lamp may suffice. For larger areas, I generally go up to 150W or more, depending on the canopy and the requirements of the species. It is important to check the manufacturer's specifications for PAR (Photosynthetically Active Radiation) and PPFD (Photosynthetic Photon Flux Density) for an accurate assessment.

The ideal distance between your LED grow light and your plants is crucial and varies according to the power of the lamp and the needs of your plants. Generally, I recommend starting at a distance of about 30 to 60 cm for most medium-power LED lamps. If you observe signs of burning or bleaching of the leaves, the lamp is too close; if the plants are stretching (etiolating), it is too far. It's a balance to be found through observation.

The number of hours of daily lighting, or photoperiod, is a key factor. For most green plants in the vegetative growth phase, I recommend a cycle of 14 to 18 hours of light per day, followed by a period of complete darkness for rest. For flowering or fruiting plants, this cycle can be adjusted to 12 hours of light and 12 hours of darkness, depending on the species. The important thing is to respect the plant's natural rhythm.

The choice of light spectrum is essential. For vegetative growth, I favor a spectrum with a dominance of blue light, which promotes dense and robust foliage. For flowering and fruiting, a spectrum rich in red light is more appropriate, as it stimulates the production of flowers and fruits. Many modern lamps offer a full spectrum that covers all stages, which I find very practical for amateur growers.

To know if your LED lamp is suitable, I invite you to carefully observe your plants. Signs of good adaptation include vigorous growth, vibrant green leaves, and the absence of overly long stems or yellowing leaves. If your plants appear to be etiolating, or on the contrary, show signs of light stress (burnt, discolored leaves), it is an indicator that the lamp is not optimal, whether in terms of power, spectrum, or distance. I always check the specific needs of each species.

For optimal installation, I start by securing the lamp using robust hangers, making sure it is stable and level. Then, I adjust the initial height according to the manufacturer's recommendations and the needs of my plants, as I mentioned earlier. I don't forget to use a timer to automate the lighting cycles and ensure a constant photoperiod, which is crucial for the health of your plants. Good placement ensures uniform light coverage over the entire canopy.