Lighting Could bulb efficiency effect internode spacing in veg?

[mclovin478910]

Hey guys so going into week 3 of my grow and got some concern with my old bulb. I know i need to replace my 3 grow old 600w HPS bulb but is it causing my tight node on my babies?

My last grow i was a 2 grow old 400w HPS and thought i had ruled lamp height out as I purchased a new one and didnt see a jump. so figured it was 2 unique phenos.

Well with my current grow underway im seeing simliar results with my old 600w bulb (purchased this setup for a steal).The lamp has been between 23-35in from the tops. attached is current grow pics at day 16 with some testers from S_A_H.

in my sig their should be a link to my last grow "another fun run" where my plants didnt finish taller than 20in.

I was under the impression tight node spacing (ruling out genetics) was a result of more intense light not an inefficient old bulb.

Thanks in advance for any input its all greatly appreciated. might give me a push to replace my old bulb sooner than later, plan is to switch right before or after the switch to 12/12.

 

[Muddy]

I don't think your node spacing looks bad. They appear in the pics to be about 1/2" apart, which is what I would expect in a 3 week old plant. That will probably end up around 1" as they grow more, which is what I always shoot for. If that's too tight for you, I'd just raise the light up a little higher.

Most MH/HPS bulbs have a rated life of 20,000 hours. From charts I've seen, they maintain nearly full output for 75 - 80% of their useful life, or about 15k hours. Running at 20 hours a day for 3 months, they should be good for 8 grows. Running photos at 12/12, they should last for at least 12 grows, including some time at 18 hours for veg.