Bud Density - Light, Strain or Both?

So I've read a few threads on this subject now and I'm still not clear. I'm hoping that someone can add some clarification.

Right now I'm flowering 9 White Widow plants under 2x 600w HPS lights. I keep the lights about as close as I can to the top of the canopy without causing serious heat issues or stress to the plants.

I've read that light is the key to bud density. I'd really like to grow some rock hard nugs and while my WW isn't loose and airy it's definitely not rock hard.

I know I've purchased some nice rock hard nugs in the past. Namely some Romulan I bought about 6 months ago.

I'm curious is some of this has to do more with the strain. I'm wondering if maybe my strain of WW just isn't going to produce really hard nugs.

Would anyone care to weigh in and maybe share some experiences? Thanks in advance.

A good grow is the SUM of ALL PARTS

this bud is in the 7th week of flowering under one 65 watt CFL

knowing how to dial in the variables is what makes dense buds

read my NooB Advice thread, I will teach you how

in my experience sativas are usually (not always) more fluffy, whereas the indicas are roch hard...
again, exceptions both ways

lights are also key,
well, light penetration

In other words, both light and strain play a variable.

adding co2 made my buds rock and molasses at the end

This is kind of the same information I've been reading.

I am not currently using CO2 but that is definitely in the plans. However, I'm thinking while light plays a roll then my primary colas that get the majority of the light would be rock hard regardless of light penetration deeper in the plant. This just isn't the case at least for me.

I've been using molasses in the last phase of flowering, but I haven't noticed much of a difference in density as much as taste.

Riddleme thanks for the link I will have to check it out.

use a homemade co2 with yeast and sugar

There are a few factors that go into bud density.

First and foremost, like you mentioned, genetics are going to be the main factor. A strain only has the potential in its genetics to get a certain density. In general (as someone else mentioned) Sativas will be loose and airy while most indicas will be more dense. Light and HEAT also play a MAJOR ROLE in density. If you have a ton of light but your room is too hot you WILL have lanky loose airy stringy buds. I would say heat plays a larger role than light when you start getting up to high temperatures. Keeping your lights too close WILL have a detrimental affect on bud density so keep a CLOSE eye on the temps.

I have had the same problem! and the answers aren't clear.

Is It the Nutrients?
In my search for them I have bought many a nutrient. I have found gravity to be pretty successful at tightening nugs. But really there is no one product that can do it.

Is it the method?
I use to do organic soil- see my first journal (havent done one since, sorry) I now do DWC hydro with Advanced Nutrients. My nugs ARE much bigger and of much higher quality, but their tightness, while it has improved- is still not that desired tightness.

Is it the light

Having seen things like riddleme with my own experience in a CFL test cabinet I have learned that it is not just light that makes nugs harder- you can grow very tight nugs with low light given proper care and a perfect controlled environment. Having said that I believe it may be a short cut and will now be doubling my flowering room from one 400watt to 2 400watt hps aircooled. We'll see...

I think most likely it is the strain.
Having grown dense nugs before of a certain Indica variety, and never having grown dense nugs of landrace or pure sativas. However Greenhouse Seeds Super Silver Haze was quite dense as was my White Widdow and my Trainwreck. Greenhouse seeds are great for showing you what you get on their website. I've grown their landrace sativas Nevilles Haze and Hawaiian snow- buds will be fluffy no matter what. And nevilles haze will shed every leaf by its 14-15 week flowering.

I would suggest you check out Trainwreck, it has the most unique calax formation- this is why, especially recently its a breeders new favorite cross. It is incredibly tight. Incredibly smelly.

Like I said my White Widdow was good... But I think it was also either a short pheno or just should have been vegged longer than the 3.5-4 i gave it. It stayed squat and yeilded pretty impressive. Tasted lemony skunk sweet.