Q. Which is a better lamp to grow with MH or HPS; I'm on a
limited budget and can only afford one?
A. If you need a lamp for only vegetative growth, go with a metal halide. If you need a lamp for both vegetative growth and blooming, and can only afford one lamp, go with a high pressure sodium.
Q. How long does the average 1000 watt HPS lamp last?
A. On average they burn for 12000 hours but most gardeners
replace once a year more maximum efficiency from the lamp.
Q. Which type of lighting is used in the vegetative stage and the bloom stage.
A. For the vegetative stage look for lighting with a blue spectrum, usually a kelvin temperature of 6500K. For the bloom stage look for lighting with a red spectrum, usually a kelvin temperature of 2000K.
Q. Can I run a 1000 watt MH bulb wired up to a socket and
just plug it in my wall plug?
A. No, you have to use a 1000 watt
MH ballast to power this lamp. The power coming out of your wall must be
transformed to usable voltage by the lamp. This is the job of the ballast.
Q. What should my light cycle be for growing indoors?
A. Since plants all have a different requirement of light
that will depend on what type of plants you intend to grow. The best thing to
do would be research the plant you wish to grow and find out its light
requirements. Most gardeners use an 18 hours of light, 6 hours in the dark
cycle for the vegetative stage and a 12 hours of light, 12 hours of the dark
cycle for the blooming stage.
Q. What is a Lumen?
A. A lumen is a measurement of light. In simpler terms one
lumen is equal to the amount of light that 1 candle will emit on 1 square foot,
1 foot away from the flame. 1 lumen = 1 foot candle
Q. What is Lux mean?
A. Lux is the metric unit equal to the amount of light
falling on one square meter 1 lumen = 10 lux A lux is only 1 / 10 th of a lumen.
Q. What is the average lumen per watt ratio of an HPS and
A. HPS - 140,000 lumens per watt MH - 100,000 lumens per
watt Fluorescent - 83,000 lumens per watt Mercury Vapor - 63,000 lumens per
watt Incandescent - 17,500 lumens per watt.
Q. When the lights are off what's going on with my plants?
Obviously they don't just sleep so what do they do?
A. In the dark cycle the plant shifts its focus from leaf
production to root production. The leaves transfer extra stored energy down to
the branches and roots. The plants dark cycle is very important. 24 hour light
cycles are not the way to go despite radical theories and tests.
Q. How high should my lights be from the tops of my plants?
A. The lamp should be 18 - 24 inches away from the tops. Use
an oscillating fan to circulate air on the tops of your plants. This will help
with the removal of heat produced by your lamp and also deliver fresh air
across the undersides of your leaves which are where the plant breathes in
through tiny microscopic pores called Stomata.
Q. What is the Kelvin rating on a bulb mean?
A. Kelvin is the unit of measurement expressing color
temperature. Each lamp has an aggregate Kelvin temperature that indicates the
bulbs spectral output. For indoor gardening a bulb with a Kelvin rating between
3000-6000 will be sufficient.
Q. Can I use a green light in my grow room in the dark
cycle? I've heard that green light won't wake up my plants?
A. Yes, you can use a green light in your grow room. Plants
do not respond to the green range of the spectrum.
Q. What is a more efficient reflector to use if my lamp is
universal, horizontal or vertical?
A. Definitely horizontal. Horizontal reflectors can reflect
up to 40 % more light back down to the growing area. The light form a bulb is emitted
form the arc tube located in the center of the lamp. If it is burning in the
horizontal position, half of this light is being directed at the plants while
the other half is being reflected back down form the reflector giving a
complete distribution of the light. If the lamp is burning in the vertical
position all of the light goes out the sides and had to be reflected back down
minimizing the intensity being directed at the growing area.
Q. What is a light mover? Are they beneficial to a grow
A. A light mover is a mechanized device used to slowly move
the grow lamps around to achieve maximum efficiency from your lamps. They come
in the form of a 6 foot track which moves the lamp back and forth slowly,
approximately every 10 minutes each way. Sun circles are designed to rotate the
lamps in a slow circular motion above the growing area. These are both very
beneficial to an indoor garden because you can bring the lamps closer to the
plants without burning and the light can get at all angles of the plant saving
the grower from constantly rotating the plants. Light mover are usually very
efficient to operate and can really help with an increase in yield without the
increase in lamps.
Q. My ballast seems to operating at a high temperature, but
how can I know if it's too hot?
A. The best way to tell if your ballast is running too hot
is to take a wooden kitchen match and touch it to the ballast box. If it ignites
the match then it is operating too hot.
Q. Does the heat coming off of my ballasts make a big
difference in my grow room?
A. Yes, if heat is already a problem in your garden then I
would suggest moving your ballasts outside the grow room. Especially if there
is more than 1. They can really increase the overall room temperature.
Q. What is the most efficient lamp to operate?
A. The 600 watt HPS is the most efficient High Intensity
Discharge lamp to operate to date. It has the highest lumen per watt ratio of
any of the HID lamps on the market.
Q. What is the best position to have my ballasts in?
A. If the ballast is mounted in a protective housing
(ballast box) then it should be kept up off the ground. Milk crates or cement
blocks are excellent for this. Place a piece of heat resistant rubber under the
box to reduce any vibrations the box may give off. They can sometimes really hum
and that can get irritating. I suggest having all ballasts mounted in proper
casings. Un- protected ballasts are usually trouble waiting to happen.
Q. I have tomato seedlings under a fluorescent light and was
wondering what my light cycle should be?
A. The light cycle should be at 18 hours of light and 12
hours of darkness. This will be best for optimal growth and will help keep the
seedlings stocky and short rather than elongated and weak. The plant needs to
sleep. This is where it goes from leaf production in the day to root production
Q. How important is it to have the lights at the right
height from the plants?
A. Having your lights too far can decrease your yield
significantly. Light intensity virtually doubles every 6 inches closer the
light is to the plant
Q. How important are reflectors?
A. Reflectors increase available light by more than 30%. The
proper hood over the lamp and reflective materials on the wall can double the
growing area. Growers who use the most efficient reflectors can harvest up to
twice as much as those who hang the lamp with no reflector.
Q. What is an air-cooled reflector?
A. There are several air cooled reflectors on the market
today. Some use a reflective hood with protective glass face and fans to move
the heat the bulb produces through the hood and out the ducting system. Most
people vent the heat through a carbon filter before discharging the air out of