Start with 250W MH finish off with 400W HPS .

tk86high

Member
So I did some research on the lighting system , and by what I understand I should start with a 250W MH for the first few weeks until the plant is nice and strong then switch over to a 400w HPS light to allow better flowering and budding.

Is this information I found correct please if somebody with such knowledge about this could advise me would be great.
Thanks

"Metal Halide - MH

Metal halide bulbs produce an abundance of light in the blue spectrum. This color of light promotes plant growth and is excellent for green leafy growth and keeping plants compact. It is the best type of light to be used as a primary light source (if no or little natural sunlight is available). The average lifespan is about 10,000 cumulative hours. The bulb will light up beyond this time but due to the gradual decline of light, it is not worth your while to wait for the bulb to finally burn out. If you compare their lumen (brightness) per unit of energy consumed, metal halides produce up to 125 lumens per watt compared to 39 lumens per watt with fluorescent lights and 18 lumens per watt for standard incandescent bulbs.

High Pressure Sodium - HPS


High pressure sodium bulbs emit an orange-red glow. This band of light triggers hormones in plants to increase flowering/budding in plants. They are the best lights available for secondary or supplemental lighting (used in conjunction with natural sunlight). This is ideal for greenhouse growing applications.

Not only is this a great flowering light, it has two features that make it a more economical choice. Their average lifespan is twice that of metal halides, but after 18,000 hours of use, they will start to draw more electricity than their rated watts while gradually producing less light. HPS bulbs are very efficient. They produce up to 140 lumens per watt. Their disadvantage is they are deficient in the blue spectrum. If a gardener were to start a young plant under a HPS bulb, she/he would see impressive vertical growth. In fact, probably too impressive. Most plants would grow up thin and lanky and in no time you will have to prune your plant back before it grows into the light fixture. The exception to this is using a HPS light in a greenhouse. Sunlight is high in the blue spectrum which would offset any stretching caused by HPS bulbs."
 

KT420

Active Member
roughly, yes, but there is more to it that just HPS/MH, you also need to look at color spectrum. MH seems to come in widely varying temperatures. Plantmax recommends these MH temps for their respective uses

7,000K Step 1 Starting / Vegative Growth - Approx. 23% Cycle
3,000K Step 2 Flowering Growth / Bloom - Approx. 60% Cycle
10,000K Step 3 Blooming / Finishing - Approx. 13% Cycle

I think replacing the 3,000K MH in that list with a 2300K or 2700K HPS during bloom would be the ideal setup, but if you didn't want to have to have 2 MH bulbs, just run a 10,000K MH to veg and finish and a 2,300K HPS to bloom. I've only used CFLs and T5s to root and veg before placing under HPS to finish vegging, bloom and finish but I'm thinking about getting a 10,000K MH to veg and finish under.
 

bigrake

Well-Known Member
I need help please I have 400 Watt set up haven't set it up yet I'm a newbie I live in a town home and have sprinklers will and can heat set them off??????
 

tk86high

Member
I need help please I have 400 Watt set up haven't set it up yet I'm a newbie I live in a town home and have sprinklers will and can heat set them off??????
The max temp ur setup/growbox should be is around 92F anything usually over this will kill the plants , and sprinklers do not kick on until the temp is well over 200F .
If u are living in a town home u better have a good carbon filter in ur grow setup as it will get pretty smelly in there. Easier way to get caught is the smell.
 
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