Illuminated incubators (Phytotron)

The 9 key questions to ask yourself when choosing the lighting for your samples;

What type of tests?

Do you need to replicate outdoor conditions? (a daylight spectrum is surely suitable)

Or rather promote (accelerate) a process? for example with “plant growth” spectrum with mixture of monochromatic red and blue LEDs.

Or even carry out standardized tests?

Very specialized room, or general?

If your room is allocated to only one type of plants, then we can advise you on the spectrum best suited to your needs.

On the other hand, if you need to test on a wide variety of species, then a “warm white” type spectrum will be preferable.

What type of lamps?

The question almost no longer arises to the extent that neon tubes are increasingly difficult to find as manufacturers replace them with LEDs which allow similar results to be obtained with a considerable expenditure of energy. lesser.

What intensity of lighting?

The intensity is ideally expressed in micromoles/m2/s useful for your plants. Or in Lux at a specified distance from the room. But the expression in PPFD is much more precise: see why further down in the “FAQ and Links” tab).

What spectrum?

The choice of spectrum is absolutely essential to maximize the development of your samples. Below you find several examples of choices of LED strips (and therefore spectrum) recommended by their manufacturers depending on the application

What uniformity?

This is the trick question. Ideally, any scientific approach should be based on the most homogeneous and reproducible tools possible. But having perfect uniformity has a high cost, in terms of investment because we have to add sources, then in use.

Very tight tolerances must therefore be reserved for very precise research.

Photoperiodicity?

Do you need to simulate a day/night alternation (or other)? Seasons? Do a multi-year search?

Should we fear certain pests?

The environment in which your plants will grow may contain pest larvae which can develop under the influence of temperature and light. Will these pests carry disease? Or will they slow down your process?

In this case, using a little UV may be beneficial. To be tested, because too much UV can also hinder the development of your plants.

Taking advantage of the Emerson Effect to boost growth?

The Emerson effect is the increase in the rate of photosynthesis after exposure of samples to light wavelengths of 670 nm (red light) and 700 nm (infra red).

When exposed to light of both wavelengths simultaneously, the rate of photosynthesis is much greater than the sum of the effects of red light and far-red light.

By adding our “laser diodes” it is possible to boost growth by 15 to 20%

Some useful links on light: in order to understand the different measurements.

Light intensity and distance: a simple video to understand the effect of source distance on the illumination received by your samples

The light recipe (according to Philips Lighting): Intensity, Spectrum, Uniformity, Duration are the 4 characteristics to determine for optimal illumination of your samples

PAR,PPF,PPFD,PFD: a video in English to explain the different ways of measuring the radiation useful for photosynthesis which arrives on your samples:

BY: Photosynthetically Active Radiation. Unit: W/m2. Only Watts generated in the wavelength band between 400 and 700 nm are counted.

PPF: Photosynthetic Photon Flux

PPFD: Photosynthetic Photon Flux Density. Unit: micromoles/m2/s. Only photons between 400 and 700 nanometers are counted

PFD: Photon Flux Density. Unit: micromoles/m2/s. Photons between 300 and 800 nanometers are counted, because it has been found that certain wavelengths in UV and IR promote photosynthesis.

PPFD–Lux conversion. Very useful page. Be careful, the spectrum has a lot of influence on the result obtained

LEDs and plants: in this article the Belgian VEGELED research team demonstrates after 2 years of research that LEDs can also be used in a positive way in horticulture. You will also find a correspondence between the different light sources (LEDs, Neon Tubes, Compact Fluorescent Lamps, HPI (Metal Halide Lamps), HPS (Sodium Lamps). It has been shown that the quantity of photons useful for photosynthesis (mainly in blue and red) is 770% greater per thousand lux with a mixture of monochrome LEDs.

Candela, Lux, Lumen: a page that summarizes this, with additional ideas on the order of magnitude of illuminance

Vertical Farming: Philips is actively working on this growing sector

Why are LEDs more efficient than HPS lamps? The response by Philips in pictures

The Emerson effect: the Emerson effect is the increase in the rate of photosynthesis after exposure of samples to light wavelengths of 670 nm (red light) and 700 nm (infra red).

When exposed to light of both wavelengths simultaneously, the rate of photosynthesis is much greater than the sum of the effects of red light and far-red light.

Valoya-Le Blog: this blog is a mine of information on light. By one of the most advanced LED manufacturers

Light spectra by Valoya: all important parameters and their influence on plant growth

The Technical Illumination Guide by Valoya: a particularly well-done “for dummies” guide to professional lighting.

The plant growth guide by Valoya: with this document you will have a much better understanding of the influence of light on plant growth

Some useful links on plant growth

Germination – Database by species: a wealth of information which brings together in an ABC, the germination conditions of known seeds.

ISTA Germination Tests: An academic dissertation that describes the various ISTA tests for determining seed quality. Test on paper or sand. Growth intensity, accelerated aging, “Hiltner”, “cold test” tests.

ISTA (International Seed Testing Association): Seed Quality Assurance.

ISTA rules 2021: introduction

ISTA rules 2021: certificates

ISTA rules 2021: sampling

ISTA rules 2021: seed health test

Grow lights for plants: a particularly detailed New Zealand blog article on the best lights for different types of plants.