| Hydroponics, greenhouses, indoor gardening, growing | | | | possible to achieve using MH-lamps or fluorescent |
| aquatic plants, food production and plants propagation | | | | lamps, which resemble full sunlight. Foliage plants may |
| – all of these fields use grow lights. Mostly, it is | | | | grow best in the shade, thus, incandescent lamps |
| done on an industrial level, although, non-professional, | | | | may be enough for them. |
| domestic gardeners are also in a habit of using grow | | | | The growers must not forget to allow the plants to |
| lights. | | | | “rest” ensuring dark periods (similar to the |
| Increasing light efficiency is often of vital importance | | | | night in the natural environment). Some plants need |
| for the growers, as the farther the grow light is | | | | many hours of light and short dark periods, while |
| from the plants, the more of it is lost. Many | | | | others flourish when both periods are equal. |
| methods, techniques, and tricks are employed | | | | To sum it up, it is necessary to mention about one |
| nowadays by the growers to achieve this goal: it is | | | | more important for the indoor gardening notion: it is |
| possible to use light reflectors, to whitewash the | | | | light density – the amount of light falling on a |
| walls or cover them with reflective materials, to | | | | surface, which is measured in lux. One lux is equal to |
| group plants close together, or to move lamps closer | | | | one lumen of light falling on a square meter. To make |
| to them. For example, incandescent lamps may be | | | | understanding easier, a brightly illuminated office will |
| placed as close as 24 inches to the plants, while | | | | have approximately 400 lux, while light density of a |
| other types of light (those that produce less heat) | | | | standard candle on one square foot will reach about |
| may be about 4 inches close to the plants. | | | | 10,76 lux. |
| As for the reflective materials, white and black plastic | | | | Horticulture Grow lights comparison |
| sheeting is the most common option. The black side | | | | An interesting note about PAR watts and lumens for |
| is turned towards the walls and the white one faces | | | | MH and HPS lamps is that the correlation between |
| the plants and works to reflect the light. Using a | | | | the two is over 97%. Meaning that for HPS and MH |
| white paint gardeners choose those with the highest | | | | lights (remember the very restricted sample used |
| content of titanium dioxide to increase its reflexive | | | | here) on average there is less than 3% variance |
| abilities. Other types of sheeting include Foylon | | | | when estimating PAR watts from lumens. But |
| (foil-laminated fabric), Mylar, or Astrofoil (heat and | | | | remember that is an average and some lamps the |
| light reflective sheeting). | | | | difference may be much more. |
| Light requirements of plants | | | | |
| It is the real science of adjusting light to the | | | | An interesting note about PAR watts and lumens for |
| requirements of peculiar plants. Indeed, various herbs | | | | MH and HPS lamps is that the correlation between |
| need different amount of lighting, and that used in | | | | the two is over 97%. Meaning that for HPS and MH |
| the indoor gardening should mimic that of the natural | | | | lights (remember the very restricted sample used |
| surrounding. Furthermore, along with the kind of the | | | | here) on average there is less than 3% variance |
| plant grown one should take into account its growth | | | | when estimating PAR watts from lumens. But |
| stage and even size. Thus, having provided optimal | | | | remember that is an average and some lamps the |
| light, a gardener may expect the best yields. | | | | difference may be much more. |
| Let us say, the richest crops of vegetables is | | | | |