Any idea's whats going on here???

So I'm absolute newbie first grow this year decided to grow outside as sufficient funds were not available to grow indoors, the plant itself is about 16 weeks old around 5 weeks into flowering, it is in organic soil and hadn't had any nutrients up until about 3 weeks ago, growth has increased dramaticly but i have noticed a brown/black/yellowy patch appear on the stem and also some discolouration in some of the lower buds. oh ive also been at war with the spider mites for about 5 or so weeks i have no idea when this thing is likely to finish flowering feels like its been going on forever :/ thoughts and ideas people?

when they look like this your plant is ready to harvest. Here your self some neem oil and spray that bitch it'll kill spider mites/ whatever then go to radio shack and get a pocket micro scope. Hope this helps Happy growing

Um that might be some fungi type shit you'll have to wait for someone with some experience to see this. I would go to plant problems on the forum and look around until someone can say for sure What's going on I didn't look at all the pics before I responded. Getting the neem and micro scope is a must have anyway. So I would get them if you can. Happy growing