HPS and MH different lamps

Author: Scott  


Dear Scott, I am starting out in growing orchards, and some small vegetable plants like lettuce, tomatoes,beens. I have approx 6.5m2 to work with inside my shed 2.5m X 2.5 roughly can you tell me what the difference is between the following 600w pressure sodium bulbs? philips Son-T Plus General electric Luca grow 600w powerplant HPS 600w also I have been told that the 600w Metal halide superveg 600w will provide more leaf and lateral growth? is this correct? is there any way I can find out what PAR or lumens these lights put out? and what height above the plants should I have the lamp? Regards, P


1. Sunlight is much more suitable than Lighting as its free and brighter, however lighting gives you seasonal control, away from pests.

2. A 600W will cover 1.5m x 1.5m maximum. Lights will not generally penetrate more than 60cm of foliage, so wise use of tying down plants, use of trellis or netting will benefit you.

3. Son T has not got enough blue, burns hotter and less bright. Its not much different to a street light.

4. GE Lucagrow is my preferred lamp, best overall grow and flower spectrum, lower heat output, very bright

5. Metal Halides are a white/blue light spectrum, and generally not necessary, but will provide more leafy growth and encourage more branching. Not as efficient in light output as a HPS lamp.

6. Son T approx 70,000 lumens – much of it in wrong spectrum

7. GE Lucagro 89,000 lumens approx – some of it in wrong spectrum.

8. PAR lighting is a term first coined by Venture lighting USA, and I understand, is heavily weighted towards what THEY think is the best spectrum, based on what levels of sodium, Xenon, etc that they want to put in the tube. Venture makes Agromaster, Sunmaster, and other OEM lamps for store chains. They are cheaper than many for us to buy and the last time I had one running in my store it exploded. I still find bits of glass occasionally. I believe the concept of PAR to be good. Not sure about whether PAR is accurate or not.

9. Heat is the issue. If you consider the reason the lamp is not close to the lamp is due to the heat, you should have the lamp as close to the plants as possible without burning them. Since plants grow well in the same climate you and I feel comfortable, put you hand under the lamp, find the point that would be uncomfortable to you, and keep plants out of that area. If your room is cool, well ventilated, very breezy, humid/dry, bulbs horizontal not vertical, all have an effect. If you keep a fan on the lamp, you can bring the lamp closer, and get say 10-20% more light on the plant. This is the major way a plant gets energy, so more light will directly affect the growth rate of a plant.

10. Try reading the growing guides at http://hydrocentre.com.au/growing-info/ and a lot of questions may be answered.

Have a good day
Scott Andrew
Nerang Hydroponic Centre
4/50 Spencer Road Nerang QLD 4211 Australia
Phone (07) 5527 4155 (Phone is always recommended for urgent problems or dilemmas as email can take several back and forth’s to achieve a solution)
scott@hydrocentre.com.au (Recommended for non-urgent items)
email checked morning and afternoon minimumon week days only


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