Why do plants need light?
Light is essential to plant survival. If you remember back to school biology lessons you may remember that plants need light to photosynthesise. This is where plants use the energy of light, Carbon dioxide (CO2) and water (H2O) to produce sugar. Plants then use this sugar to build other chemicals such as proteins and for growth.
Sunlight is made up of a whole range of colours of light or spectrum. Plants use different parts of the spectrum for different purposes.
Blue light is used by the plant for vegetative growth (leafy growth) generally keeping the plant nice compact and bushy.
Red light is essential to plants for fruiting and flowering, the plants becoming elongated possibly in the hope of being pollinated.
When using artificial plant lighting it is possible to prevent your flowering plants from getting too stretched (etiolated) by ensuring they still receive adequate blue light.
It is a general misconception that plant lighting is hydroponic lighting however it is not essential to use artificial lighting with your hydroponic system or visa versa as long as the plants you want to grow are getting adequate light. Some people want to grow where there is not enough natural light or grow in a place where there is no natural light for example a basement and therefore need a plant grow light.
What types of plant lighting are available to me?
Commonly used plant grow lights are usually either fluorescent lighting or HID (High Intensity Discharge) lighting.
Fluorescent tubes provide light without the problem of excessive heat output, which means that you the grower can have the light tube close to the top of the plant thereby maximising light without scorching or burning.
You may use fluorescent tubes to provide light for mother plants, cuttings and seedlings, avoiding the heat problems associated with HID lamps. Fluorescents may also be hung in among plants to ensure that lower parts of the plant receive adequate light.
Highly recommended fluorescent lamps are the Ecolight® compact fluorescent (CFL) range which are available in Red spectrum 2700k, Blue spectrum 6400k and Purple spectrum 25000k.
HID (High Intensity Discharge):
These lights comprise metal halide (MH) lamps, high pressure sodium (HPS) and and the now relatively obsolete Mercury vapour lamps.
Both HPS and MH give off vast quantities of light and a fair amount of heat, therefore it is essential that the lamps are kept a safe distance above the tops of the plants. A good indication of a lamp being to close is that if it burns the back of your hand at the plant tops it will burn your plants.
Some elegant solutions are available that allow you to get the lamps closer to your plants without harming them such as the Super-spreader ®, reflectors with air extraction and light movers. Generally the closer the lights are to your plants the quicker your plants will grow.
HPS are rich in the red-orange-yellow part of the spectrum and are used for flowering and fruiting and they have a warm orangey yellow glow to the naked eye. Examples of HPS lamps are Philips Son-T+ and Osram NAV-T super.
MH lamps are extremely rich in the blue part of the spectrum and are generally used in the vegetative part of the plant life cycle. They look a cool white sometimes with a bluish tinge to the naked eye. Examples of MH lamps are Philips HPI-T and Osram HQI-T
However there are lamps available that offer a combination of the blue and red spectrum, these lamps have the advantage of being suitable for both the vegetative growth phase and the flowering growth phase. Examples of these are the Philips Son-T-Agro, the Osram Plantastar and the Grolux from Sylvania, these come very highly recommended by the hydroponicwarehouse.
What size lamp do I require?
It is essential to take into account the type of plant that you are growing and the size of the growing area when deciding how much light you need to provide.
For example a tomato plant requires very high light levels, so when using HPS as much as 40 watts per square foot is required. So using this information when growing tomatoes indoors the most commonly used wattage lamps will illuminate the following size areas
250w = approx 3' x 2'
400w = approx 3' x 3'
600w = approx 5' x 3'
Work out how much light your grow-room will require by calculating the area of the floor in square foot and then multiply it by 40 to get the total number of watts required. It is then a simple matter of purchasing the correct number of lights at the hydroponicwarehouse .
More experienced growers know that over a period of time the amount of light that a bulb emits drops, thereby causing plant yields to suffer. As a rule of thumb lamps should be replaced after 9 months to a year of use.
What comprises a Lighting system?
A HID lighting system is comprised of the following components:
A reflector (shade) to reflect the light down onto the plants.
A Ballast (starter box) to ignite and illuminate the lamp.
A lamp to produce the light.
There are many different lighting systems on the market today, giving you the discerning grower a fantastic choice.
So please buy the best quality system that your budget can afford, you may save £10-20 on the system price but if it has an inefficient reflector, ballast and low quality lamp the saving will be more than outweighed by a decrease in final yield of your crop and most importantly your disappointment.
When investing in a light system, ask does the ballast: meet CE regulations? have frequency matched components? operate silently? come with a full warranty?
The hydroponicswarehouse only present top quality systems for your satisfaction, having efficient reflectors, frequency matched ballasts that are cool running,silent and with top quality BRANDED lamps.