Are 2100K hps lights the right spectrum for marijuana??

RichiRich

RichiRich

Active Member
marijuananation said:
Are 400 watt 2100K hps lights the right spectrum for marijuana??

+++REP

THESE LIGHTS BELOW:
https://www.acklandsgrainger.com/AGIPortalWeb/WebSource/Search/doRemove.do?item=GELLU1000ECO&JSESSIONID=Wh3dL2PfySJwXVl3LKGppJjr1TvwZfMbyp1pYmx3GS9kCR2XQ0kg!-3193635!1266077535819
Click to expand...

Just use google next time, mate. It's much more simple than creating a thread and waiting for people to post.

Anyway, this is what I can make of it. As you can see 2100k is in good range for plant growth... 400w is not bad either, so I'd say go for it. However, wait for some more opinions just to be sure...

-Rich

 
Hobbes

Hobbes

Well-Known Member
.

Hey Marijuananation!

"Are 400 watt 2100K hps lights the right spectrum for marijuana??"

For flowering in an area not larger than 8 square feet. (400W / 50W/'sq) = 8'sq. Watts will give you light output and intensity which tells you how large of a garden you can grow and how deep into the canopy the light will penetrate.

A 2100K light could also be used for seedlings, first week. Will cause stretching.
Hortilux Super HPS can be used for both flower and veg but still requires experience to reduced stretch.

The very simplest way to think about lighting:

Veg: MH or florescent for veg. Kelvin temp of light 4000K (blueish) or higher, I use a 14,500K compact florescent (middle bulb in drawing below) for early veg and a 150W 2100K HPS (bulb drawing on left below) 2 weeks before flower.

Flower: 2100K HPS (redish). You can use a lot of other things but start simple.

.



.

bongsmilie
 
Jhanzi

Jhanzi

Active Member
Cannabis is like a lot of other plants in that it grows robustly during the summer, then devotes itself to reproduction as fall sets in - the great life/death/rebirth cycle:). During its vegetative phase, cannabis appears green (and grows, well....like a weed) because the predominant pigments (chlorophyll a and b) are geared more towards absorbing higher-energy (shorter wavelength or higher "temperature") blue and violet light, which is abundantly present in the white light from the summer sun. The light that is reflected is only the portion of white light that isn't absorbed by the plant (the same concept applies to anything with color - we only see the wavelength(s) of light reflected into our eyes). This is the first step of photosynthesis - capturing the sun's energy through light-responsive pigments. As the plant reaches the end of its life (generally during the fall), chlorophyll degrades and the remaining pigments become predominant and more visible (hence the yellow/red/orange leaves on trees in the fall). These pigments absorb lower-wavelength (more "reddish") light. This is why most growers will use "bluer" metal halide lamps during veg then switch to "redder" sodium lamps or similar for flowering. This doesn't mean that an entire crop can't be successful with just one type of lamp - heck, my small hobbyist setup runs off one HPS lamp and does fairly well. Just make sure your lamps are the proper wattage for the area you're using (otherwise the growth directly under the canopy will remain too shaded).
 

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