Metal Halide switch

[acheron11000]

i currently have 2 white widow seedlings under 3 13 watt cfl bulbs. today my 400 watt metal halide/hps ballast and hood kit came. and i was just curious what kind of difference i will see in the growth. (will it make the plants grow faster, bigger leaves etc.)
i have a good ventilation system in place as well as an air cooled hood with wings. im growing in very good soil and will be using nutrients from fox farms quite soon. i plan on supercropping and other techniques. ive tested the soil's nitrogen phosphorus and ph as well as the water. ph is at 6.7-6.9 which is good for soil.
any other tips or suggestions would be greatly welcomed thanks guys!

 

[Rodrigo]

What you need to know is that the plants use different light spectrums and temperatures (light T°, not actual T°) for veg and for flower.

So for veg it doesn't really matter which light you use. A cool light with a T° of about 6700K is the common recommendation and it's proven that this is the best temp for veg. I have a mixture of cool and warm lights and I'm very very happy with the results, my plants grow very bushy (which is good because there are more bud sites). I don't remember the spectrum but I think is on the red side of things.
In my opinion the cost of running a HPS/MH for veg is not worth it and T5 and CFLs are enough.

For flower the light you use actually does matter. It's been proven that HPS is the best for flower because it delivers the most to the plant. Some people like to mix HPS and MH to get a broader spectrum. Although I don't know if it makes any noticeable difference. HPS is a warm light with a T° of about 2700K (I Think) which is the best temp for flower. The spectrum I think is towards the blue side.

Good luck!

 

[oldhippie64]

it's going to hard to say how much faster/more it will grow since we don't know all the conditions or how well it was doing before the switch. I think Rodrigo has his colors reversed but the K and lighting plan is correct, 6500k is a bluish white and 2700k is rediish white.