Light Cycle Question

[Dark Ninja Mark]

Okay, so I am now understanding that MH light is good for vegative growth. It puts off a blue spectrum that supports strong root growth. And HPS is good for flowering growth, due to orange and red spectrum that imitates the natural sun.

So, my question is. When does the vegative stage begin? My understanding is the vegative stage begins when there are multiple sites of 4 leaves? Sorry if that sounds dumb, any info regarding this would be great.

And when would it be effective to start using MH lights?

Thanks guys!

 

[santie99]

The vegitative state is basically the state the plant is in when you are using an 18/6 or 24/0 lighting cycle. Or anytime you are not in a flowering light cycle of 12/12.

Are you using florecents now? Unless your room is dry and warm, i'd say switch to the MH right away.

 

[Rosy Cheeks]

There's no exact boundary between seedling/clone stage and vegetative state, these are just definitions we've created in order to make plant physiology a more exact science, but let's say that a plant enters the vegetative state when it has a root system capable of nourishing the plant and making it grow, while photosynthesis kicks in and makes the plant green. When a young seed plant has one or more nodes with three fingered leaves I do concider it a plant in the vegetative state. Cool white fluorescent light normally falls within the 5000-4000 Kelvin light spectrum range and is great for young plants, that particularly appreciate this light. The output - normally between 30w-60w/5000-10 000 initial lumens - is just enough and not overkill. The disadvantage with fluoros is that light intensity degrades rapidly with distance, but they can be kept very close to the plant without burning it. Metal Halides put out a light in the 6500-5000 Kelvin range (where some fluos go too) and is perfect for vegetating plants, since this light spectrum builds compact, robust plants with very short internode lenght. If using horisontal directed light, an MH grown plant will be better aligned under the light and profit from better overall bud site light coverage. The Metal Halide is a High Intensity Discharge light though, with a higher infrared light output than fluoros, meaning that they get hot. I personally don't see any point in vegging with less than 250w of light (a lot of microgrowers choke on their coffee now, I know), which means a minimum of 20 000 lumens, and most serious growers will use 400w bulbs (around 30 000 lumens), which will put serious heat stress on a very young plant, where the upper epidermis (the waxy surface) and leaf structure isn't yet resistant enough. Your best option is to use fluoros or horticulture CFL:s until you concider the plant big and strong enough, then switch to MH that you start from a safe distance, then close in gradually. High Pressure Sodium light falls within the 3000-2000 Kelvin light range. This kind of light makes your plants grow faster and is better suited for fruit and flower development than cold light, but it also increases etiolation (stretch) in plant growth.

 

[Guest]

Wow RosyCheeks As always some very good info and a good post and it is super to see you here. peace and stay free dequilo

 

[Guest]

To me the veg stage is from the time they break the surface until I change the light to 12/12

 

[Opt1983]

I consider the Veggie state to be approx. 2 1/2 - 3 weeks after they break the surface. It's then usually that the plant really starts to take off and require nutrients. -Opt

 

[LavenderCowboy]

I consider the vegetation phase when the plant begins putting on veggetation...That's when it breaks the soil surface or even before....The seedleaves have formed in the seed as the seed breaks open....

IMO, if a grower was to choose one light to grow under, they should choose an HPS for all phases of growth except seedling...Seedlings should be under flouro's as Rosy Cheeks says....LC