Using feed that contains more P & K will not starve the plants of nitrogen because your fert should still have a bit of N in the solution..Because it still needs nitrogen and I wouldn't ever recommend starving your plant of anything until it's 2-3 weeks prior to the harvest..every single nutrient is essential to the growth of the plant but more bloom ferts will cause it to use less nitrogen for leaf and growth overall and focus more on blooming and producing their flowers. I suggest you get some kind of bamboo stick or something similar and tie it around the pot and tie your branches to that to hold it up, I had a similar problem with my heavy buds. Doesn't matter about the density, (or how compact they are) they are just weighing more than what the stem can hold. Also you guys should have been feeding them the right blooming nutes LONG before 7 weeks of growth, if it's a Sativa you might have a maximum of 6 more weeks of growth...maybe. If it's a hybrid it might be sooner but usually Sativas do take longer to grow, mines is a hybrid and it's going to take around that long as most Sativas do. Some take even longer. And as for branch thickening there might be some solution but IMO most Sativas I have seen just have lanky branches and usually do need support but it doesn't really matter to me, if you give it the support it needs, skinny branches or not it can give you fat fuckin' nuggets! :thumbsup: