An Introduction To Hydroponics Gardening For Beginners (Part 3)
By John R. Haughton
1 - Part
2 - Part 3 - Part
4 - Part
THE BASICS OF HYDROPONICS.
An Introduction To Indoor Plant Grow Lights.
There are basically three types of grow lights used in horticulture.
High Intensity Discharge Lights. (HID)
These come in two types, the Metal Halide Grow Light(MH) and the
High Pressure Sodium Grow Light (HPS)
Metal halide bulbs are designed for plants during their growing cycle.
That is, for non-fruiting or non-blooming plants. Metal halide
lighting is therefore the best HID choice for the plantís growing
High Pressure Sodium Lights.
The HPS grow light is used primarily for plants that are in their
blooming or fruiting phase. Modern high pressure sodium lighting can,
however, be bought, which is enhanced for blue spectrum (for
vegetative growth) and for red spectrum (for flowering growth). This
means that they can be used throughout the entire growing process for
most types of plant.
Dual light Systems.
For optimal performance, switchable systems (400 watt and 1000 watt)
and dual light systems (250 watt MH + 250 watt HPS giving 500 watt
output, 400 watt MH + 400 watt HPS giving 800 watt output and 400 watt
MH + 600 watt HPS giving 1000 watt output) are available. This type of
grow light system gives the best all round lighting choice.
Mercury Vapor Lamps.
Phosphorous coated to promote both blue and red spectrums these lamps
are suitable for both the growing and blooming stages of plant growth.
They give off more blue light that red and are a cheap way to get
started, however the lamp wants replacing every nine months as it can
become volatile. Mercury vapour lights cost more to run and maintain
compared to HPS, MH or fluorescents.
Fluorescent Grow Lights.
These lights emit less light than high intensity discharge lights and
although they can be used throughout the plant cycle their lack of
brightness will produce small yields. The light produced tends to be
softer and less damaging to tender young plants. For this reason, the
fluorescent grow light is popular for seedlings and cuttings, an
excellent way to establish young plants.
All of the above types of lights use some kind of a ballast system.
The one most people are familiar with is the fluorescent light. This
has, a small, built in, ballast. It allows the fluorescent tube to
build up enough energy to strike, and excite the molecules within the
tube, causing light to be given off.
Metal Halide and HPS grow lights are usually run from remote
ballasts. These are external boxes containing the electronics to
pre-heat and run the lamp. The ballast is connected to the lamp holder
and to the mains power supply. Each ballast used is rated for the lamp
wattage and so it is necessary to have different ballasts available
for each of the different values of lamp to be used. HID bulbs should
be replaced after 12 to 18 months of use. Although HID lamps will
continue to light beyond 18 months of use, they will have lost up to
30 percent or more of their lumen output while consuming the same
amount of electricity.
Mercury Vapor Lights.
Most of these lamps, up to a value of 500 watts, require no additional
ballast. You just screw them into the lamp holder supplied with your
Here is a word of warning about lighting.
There are an awful lot of companies out there selling lights for the
hydroponics enthusiast. As in all walks of life, there are good and
bad suppliers and manufacturers of lighting equipment. Always look for
equipment made by a reputable company and backed by an official
testing scheme. (For example the C E mark in Europe means that the
article is up to European standards of safety and quality).
Cheap, nasty, home made, dangerous lights have dogged the
hydroponics market for some years. There are these kinds of light and
there are well built, professional grade, horticultural lights on
today's market. The first are often death traps, being cobbled
together from the cheapest, obsolete, end of the line components that
are usually mismatched and wrongly configured.
To think that these poorly built, badly wired, mis-configured
lights are being fitted in damp, humid and sometimes even wet, grow
rooms is a very scary thought indeed. The installation of these poor
quality, dangerous, lights in your home, where your family lives and
plays, is always a very grave risk. All this in the name of a bargain!
So donít risk your own life or the lives of those who live
with you. Buy from a reputable source! Lighting is possibly the most
important decision for indoor horticulture, cheap normally represents
a health risk. For the sake of saving a relatively small amount of
money, is it really worth it?
You have been warned!
Copyright (C) 2004, 2005 J R Haughton. --- All Rights Reserved ---
A partner in a thriving retail hydroponics supply business, Rickie
Haughton is the owner of http://hydroponics-gardening-information.com/
which aims to cater for all levels of expertise in the field of
hydroponics gardening. The website is packed with good content about
all aspects off hydroponics gardening and offers a free newsletter to