Table of contents:
- Plant lighting
- Incandescent lamps
- General purpose fluorescent lamps
- Fluorescent lamps for special purposes
- Compact fluorescent lamps
- Discharge lamps
- Mercury lamps
- High pressure sodium lamps
- Metal halide lamps
Video: Additional Lighting Of Indoor Plants. Artificial Lighting Systems. Special Lamps For Plants. Specifications. A Photo
- Part 1: Why light plants. Mysterious lumens and suites
- Part 2: Plant Lamps
- Part 3: Choosing a Lighting System
This article will look at the types of lamps used to illuminate plants.
Such lamps are of two types - incandescent lamps, in which there is a spiral, and gas-discharge lamps, where light is generated by an electric discharge in a mixture of gases. Incandescent lamps can be directly plugged into the outlet, gas-discharge lamps require special ballasts, also called ballast. These lamps must not be plugged into an outlet, although some of them resemble incandescent lamps with their caps. Only new compact fluorescent lamps with integrated ballast can be screwed into the socket.
These lamps, in addition to the usual incandescent lamps that are screwed into the chandelier on the ceiling, include some other lamps:
Halogen lamps, which contain a mixture of gases inside the bulb to increase the brightness and lamp life. Do not confuse these lamps with HID lamps, often referred to as metal halide lamps. The new lamps use a mixture of krypton and xenon gases. Due to this, the brightness of the glow of the spiral is even higher.
Neodymium lamps, the bulbs of which are made of glass with an admixture of neodymium (Chromalux Neodym, Eurostar Neodymium). This glass absorbs the yellow-green part of the spectrum and the illuminated objects appear brighter visually. In reality, the lamp does not give more light than a regular lamp.
Incandescent lamps should not be used to illuminate plants. They are not suitable for two reasons - there are no blue colors in the spectrum (in the first part it is written about this) and they have low light output (17-25 Lm / W). All incandescent lamps are very hot, so they should not be placed close to plants, otherwise the plants will get burned. And placing these lamps at a distance of more than one meter from the plant gives practically nothing. Therefore, in indoor floriculture, such lamps are used exclusively for heating air in greenhouses and greenhouses. Another application of an incandescent lamp is in conjunction with a fluorescent lamp, in the spectrum of which there is little red light. For example, the combination of a cold light bulb and an incandescent light bulb has a fairly good spectrum. However, it is better to use a sodium lamp instead of an incandescent lamp.
Recently, special lamps for plant illumination have appeared on the market, for example the OSRAM Concentra Spot Natura with a built-in reflector. These lamps differ from the usual ones in price (about 80-100 rubles in Moscow for a 75-100 W lamp). But the principle of operation, and, consequently, the efficiency of these lamps is the same as that of conventional incandescent lamps.
General purpose fluorescent lamps
Lamps of this type are known to everyone - standard light sources in rooms. Fluorescent lamps are more suited for plant illumination than incandescent lamps. Among the advantages are high light output (50-70 lm / W), low thermal radiation and long service life. The disadvantage of such lamps is that the spectrum is not entirely effective for illuminating plants. However, if there is enough light, then the spectrum is not that important. These lamps require
lamps with special control gear (ballast, ballast). This equipment is of two types - electromagnetic (EMPRA - a choke with a starter) and electronic (ECG, electronic ballast). The second is much better: the lamps do not flicker when switched on and working, the lamp life and the amount of light emitted by the lamp increase. Some electronic ballasts allow you to adjust the brightness of the lamps, for example, from an external light sensor. There is only one problem, if the simplest choke costs about 200 rubles in Moscow, then the prices for electronic ballasts start at 900 rubles, and regulated electronic ballasts cost more than 2,000 rubles without a regulating device, which costs another $ 70 to $ 90 (one such device can serve many lamps).
The power of the lamp depends on its length. Longer bulbs give more light. If possible, longer and more powerful lamps should be used, since they have a higher light output. In other words, 2 x 36W lamps are better than 4 x 18W lamps.
Lamps should be located no higher than half a meter from plants. The optimal use of fluorescent lamps is shelves with plants of approximately the same height. Lamps are mounted at a distance of up to 15 cm for light-loving plants, and at a distance of 15-50 cm for plants that prefer partial shade. In this case, the lighting is mounted along the entire length of the shelf or rack.
Fluorescent lamps for special purposes
These lamps differ from general-purpose lamps only by the coating on the glass envelope. Due to this, the spectrum of these lamps is close to the spectrum that plants require. In Moscow you can find lamps from such manufacturers as OSRAM-Sylvania, Philips, GE, etc. Russian-made lamps with a spectrum optimized for plant illumination do not yet exist.
Prices for specialty lamps are at least double that of general purpose lamps, but sometimes it pays off. As an example - the personal experience of one of the authors (A. Litovkin): When the first winter crept up to my plants, I noticed that they began, if not to wither, then obviously stopped in development. It was decided to illuminate them - a lamp was installed on two lamps of 1200 mm. At first, domestically produced lamps with cold white light were installed in it. The plants perked up noticeably, but they were in no hurry to get under way. Then, after about a month, the general purpose lamps were replaced by OSRAM Fluora. And after that, the plants, as they say, “flooded”.
If you are installing a lamp instead of an old one, then it makes sense to use a specialized lamp for plants, since at the same power such a lamp gives more "useful" light for plants. But when installing a new system, it is better to put more powerful conventional lamps (best of all, high-power compact fluorescent lamps), since they give more light, which is more important for plants than spectrum.
Compact fluorescent lamps
These lamps are available with or without built-in ballast. In Moscow, there are lamps from leading world manufacturers and lamps of domestic production (MELZ), which are almost as good as foreign analogues in terms of characteristics, and are significantly cheaper at a price.
Lamps with built-in ballast differ from extended general-purpose fluorescent lamps only in their smaller dimensions and ease of use - they can be screwed into a regular holder. Unfortunately, such lamps are produced to replace incandescent lamps for indoor lighting, and their spectrum is similar to that of incandescent lamps, which is not optimal for plants.
These lamps are best used to illuminate several, compactly standing plants. To obtain a normal luminous flux, the power of the lamps must be at least 20 W (analogous to 100 W for an incandescent lamp), and the distance to plants must be no more than 30-40 centimeters.
Currently, there are high power compact fluorescent lamps on sale - from 36 to 55 watts. These lamps are characterized by an increased light output (20% -30%) compared to conventional fluorescent lamps, a long service life, excellent color rendering (CRI> 90) and a wide spectrum, which contains the red and blue colors necessary for plants. Compactness allows efficient use of lamps together with a reflector, which is important. These lamps are the best choice for plant illumination, with a low power of the lighting system (up to 200 W of total power). The disadvantage is the high cost and the need to use electronic ballast for high power lamps.
Discharge lamps are by far the brightest light source. They are compact in size. High luminous efficiency allows one lamp to illuminate plants occupying a large area. Special ballasts must be used with these lamps. It should be noted that it makes sense to use such lamps if you need a lot of light - with a total power of less than 200-300 W, the best solution is to use compact fluorescent lamps.
Three types of lamps are used to illuminate plants: mercury, sodium and metal halide, sometimes called metal halide.
Historically the oldest type of all gas discharge lamps. There are uncoated lamps that have a low color rendering index (under the light of these lamps everything looks dead blue) and newer lamps with a coating that improves spectral characteristics. The light output of these lamps is low. Some companies produce plant lamps using mercury lamps, for example OSRAM Floraset. If you are designing a new lighting system, it is best to refrain from mercury lamps.
High pressure sodium lamps
High pressure sodium lamps are one of the most efficient light sources in terms of light output. The spectrum of these lamps affects mainly the pigments of plants in the red zone of the spectrum, which are responsible for root formation and flowering.
From what is offered for sale, the most preferable lamps are Reflax LLC "Svetotekhnika" series DnaT (see photo). These lamps are made with a built-in reflector, allow operation in lamps without protective glass (unlike other sodium lamps), and have a very significant resource (12-20 thousand hours).
Sodium lamps give a large amount of light, so a high-power ceiling lamp (250 W and above) can illuminate a large area at once, which is the best solution for illuminating winter gardens and large collections. True, in such cases it is recommended to alternate them with mercury or metal halide lamps to balance the radiation spectrum.
Metal halide lamps
The most advanced lamps for plant illumination are high power, long service life, optimal radiation spectrum. Unfortunately, these lamps, especially those with an improved emission spectrum, are more expensive than other lamps. There are new lamps with a ceramic burner manufactured by Philips (CDM), OSRAM (HCI) with an increased color rendering index (CRI = 80-95). The domestic industry produces lamps of the DRI series. The area of application is the same as for high pressure sodium lamps.
Although the base of a metal halide lamp (right) is similar to that of an incandescent lamp (left), it requires a special socket.
Instead of an afterword - what is useful and for what purpose.
If you need to whip up something cheaply, use incandescent bulbs or a compact fluorescent lamp with built-in ballast, which can be screwed into a regular holder.
Several closely spaced plants can be illuminated in several ways. A dozen small plants of approximately the same height (up to half a meter) are best illuminated with compact fluorescent lamps. For tall single plants, we recommend floodlights with discharge lamps up to 100 watts.
If plants of approximately the same height are placed on shelves or on a windowsill, then use extended fluorescent lamps or, even better, high-power compact lamps. Be sure to use reflectors with fluorescent lamps - they will significantly increase the useful luminous flux.
If you have a large conservatory, then install ceiling lights with high power discharge lamps (250 W or higher).
Most of the lamps described can be purchased at electrical stores.
In conclusion, the table shows the comparative characteristics of lamps and systems for plant lighting.
Special thanks to the toptropicals.com team for permission to publish the article on our resource.