Hey new grower I didn't post my last grow bec...

Its mostly down to genetics and some environmentals. Eg light density and CO2 levels. But mostly its all down to genetics. Not all seeds/strains are winners, most are average, some below, and the rare bits are really above it all, its why some of the best stuff is clone only as its not always the same in seeds. Seeds are sisters and brothers, and look at family's not all brother and sister looks the same or achieve the same results in life. Same as seeds.

The Temperature with which you grow through flowering can alter the density of buds.

I would reduce to : light , heat in flower, genetics, but its for healthy good grow ! Any missgrows could lead to it too . If you done everything right - only those 3 reasons are your options. If you grew in temps higher than 27 Celsius - a lot of bud will be airy. If you harvest early - you can loose density ... Ph wrong - bad nuts uptake - airy bud Weak light - airy bud ... And so on ;)))) In other words - there could be many or main 3 ;)))

It's fitting to use the term "shed some light" because it was most likely not enough light that contributed to the lack of density. Without a diary to reference it's hard to pinpoint the exact cause but I would list the factors in order of likelihood: 1. Low light 2. High humidity in flower 3. High temps in flower 4. Genetics