Best bulb for veg? and flowering?

As I understand it, the MH causes the plant to be bushy and have close nodes, while the HPS causes the buds to be bigger. The science behind that, I am not sure about, but peeps have been growing for like 30 years that way. Pretty sure the ideal is to have both.

 

Basically a Mh light and a Hps light together are heaven for a plant if you have both i would use both. But if you only have one or the other the hps is the best because you can use it all the way through the grow with amazing results. But yes mh is the best for veg.

 

Indoors, 2000 lumens per sq. ft. is about as low as you want to go indoors. If you get under this mark, plant growth will definately not go as fast as possible, and internode/stem length will increase. Also, light distance to plants will be much more critical. Daily adjustments to the lamps will be necessary, meaning you get no vacations. 2500 lumens psf should be a good target, and 3000 is optimal if your going to inject or enrich CO2 levels.



High Pressure Sodium - or HPS lamps emit a pink or amber light. They are used generally for lighting parking lots and other areas where the color of the light is not all that important. HPS lights are much more efficient than MH ones, producing more light and less energy consumed. They are often used alone with no detrimental effect on the plants, and will promote faster plant growth than MH lamps during both vegetative growth and flowering. Combinations of bulbs are _NOT_ required, as the HPS lamp does produce all of the light spectrums necessary for healthy growth. There is a relatively new type of HPS lamp that has become available. It is called the...

Son Agro lamp

Basically the designers of this special lamp took a 400w HPS lamp, and added another 30W element to it, However, this new element puts out blue light, to help fill in the parts of the spectrum that a standard HPS light is missing.




Metal Halide - Metal halide (MH) lamps can be used for vegging and flowering (but primarily vegging), but there are two problems that they have when compared with high-pressure sodium (HPS) lamps. The first is that they don't emit as much total light. HPS lamps emit more than 20% more light, so MH lamps are not as intense when covering the same area. Second, they do not emit as much orange and red light as HPS lamps. These spectrums seem to promote flowering.

However, MH lamps do have several advantages over HPS. First, they are less expensive to purchase. Second, the light does not have a really weird telltale spectrum. It looks white, not pink or amber/orange.

Third, the lamps emit more UVB light than HPS lamps, although still in very small amounts. The amount of UVB light plants receive is directly related to the quality of the harvested buds. The more UVB, the higher the quality.

Buds grown under MH light will not be as big as buds grown using HPS lighting. However their quality will be as good or better.






What is a Kelvin scale?
One way light is measured is on a Kelvin scale. A Kelvin scale expresses the exact color the bulb emits. Bulbs in the range of 2700 to 6500 on a Kelvin scale is ideal for growing marijuana.

 

Since you have both you should veg with the MH and then switch to the HPS for flowering. No need to waste the MH bulb and your plants will love it