nitrogen deficiency

when should/does nitrogen deficiency begin to show up during flowering? in other words, if my leaves being yellowing early should i be concerned or should i let it just run its course?

im not giving you enough info because i dont have enough info, these are hypotheticals so please dont flip out, just curious. if you have something useful to say about this subject, or can point me in another direction id appreciate it.

a lot of people say to let it run its course. then again you can find some very serious conversations about making sure the plants and its soil have all of the 15 (i think its 15 or 16) major nutrients. i guess if we are talking hypothetically, then you should do all the proper preparations and then you should not have to worry much about it. What I mean by this is having good soil (not necessarily expensive, but good quality) and you give the plant what it needs, and that means if it only needs water, only give it water. you dont want to give a plant nutes just to make it grow. some soils have nutes in them, or compost which does not really have nutes mixed in, but is itself nutrient enriched through the composting process. But sometimes your plants do need nutes, and you may get N defiencies during flower. some people will switch from something like a 10-30-20 to a 3-4-4. basically change up the ratio where the plant is getting more P & K than N, but more N than before, and less overall. I hope all this makes sense, got a little buzz, but I did proofread, and it made sense to me!!

But basically, read on this site and some of the other good growing sites. there are a lot of smart and nice people that hand out information all the time. simpsonandsampson420 has a great thread just for folks like you with questions, check it out here.
https://www.rollitup.org/newbie-central/212352-all-new-growers-questions-tons.html

ahh thank you for the quick and informative reply. your thoughts are the same as mine. i want to build the perfect soil to make things as simple as possible. im relatively familiar with soil compositions having grown this and that most of my life, however seeing as this is new territory for me i figured i would try and gather some good info. what i am trying to avoid is having to monkey around with any nutes at all, and simply letting my plant thrive on the soil it is in. what worries me is running out of the necessary nutes too early (ie showing a nitro deficiency early on in flower), and then being forced into a corner about using nutes or not. so this question still remains: what is too early for a nitrogen deficiency in flower, and should it/does it need to be avoided. now i may sound like the laziest son of a bitch ever but realistically i just like things clean and simple, and to run as they are desired. any of these little bumps that i can avoid now will be greatly appreciated down the road, so any help and insight mean a bunch to me.

edit: and i have to admit i havent read that link yet, but im heading there now...!

Alot of guys make the mistake of switching to bloom fert too early, and then their plants burn up all their nitrogen before they get through with the 'preflower stretch'. Wait until 2 weeks into 12/12 before you switch to bloom ferts, and that'll help alot. I just had that problem, used veg fert for two feedings, and they got alot of their green color back. How early is "early"? As long as it's not much beyond the 4th week, I'd go with at least one feeding of veg fert. As long as it's not a super-strong fert like Miraclegro, it won't hurt a thing.

Oh yeah....I don't like to see any yellowing until after the 5th week, at earliest. I believe that if they are starved too early, it'll take away from flower production, so I plan to keep my green into the 6th week, 7th week if possible. Some keep theirs green til the very end, and swear by it. Makes sense when you think about it, because in nature the soil doesn't magically run out of N during the last couple weeks of bloom, and still manages to grow some massive plants producing pounds of killer weed. If a plant is deprived, it isn't running at 100%, if you ask me.

need to use a high N food till after the stretch (3 weeks into flower) then switch to a food with a 1-3-2 ratio for flower. the soil pros use jacks classic 10-30-20. if your plants start to look like they need some N then switch back to the high N food till the leaves look good and healthy. even if youre 5 or 6 weeks into flower. the plants flower as a response to darkness, not because of what you feed it. keeping the leaves green and healthy is your #1 priority.