The success of your garden is directly related to the quality of light provided to the plants. If you are using natural daylight for your hydroponic garden, then you have the best possible light source available. Unfortunately, the amount of daylight available varies during the year and it is not possible to successfully grow certain plants year-round without supplementing daylight. If you are using artificial light provided by sources such as metal halide or high pressure sodium (HPS), you need to remember a few things:
- Bulb intensity decreases over time; as much as 30% over a year. 30% less lumens = 30% less yield
- Not all bulbs provide the optimal spectrum of light. Either get a full spectrum bulb or use two, one for the growth stage and one for the flowering stage.
- Plants also need sleep; ensure they get some darkness (at least four hours).
- Ensure you have the right sized bulb for your garden size.
LEDs are emerging as a new form of light source in the hydroponics world. They offer the promise of decreased energy usage as well as better sizing possibilities. This is somewhat new to the scene and not recommended at this point.
For further information, see our article on grow lights.