I ordered the Northern Brewer American Wheat extract kit, which calls for 2 weeks primary ferment, and 2 weeks bottle conditioning (4 weeks total).
I added my own 1 lb. of honey at flame out as an addition.

NB Honey Weissen is the exact same kit only it calls for 1 lb. of honey at flame out. It asks for 2 weeks primary, 2 weeks secondary, then 2 weeks bottle condition (6 weeks total).

Both kits use the same yeast, but different hops.

Since I added the 1 lb of clover honey, should I let it primary ferment longer than 2 weeks, or go ahead and bottle as normal at the 2 week mark? I didn't plan on secondary for this style in the first place. Is secondary necessary?

Your advice is appreciated!
Thanks!

From what I've read and heard, secondary fermentors are used mainly for fruit beers or for lagering. Most beers don't need it and do just as well if left in the first fermenter for that amount of time, 3-4 weeks instead of 2 in primary and 2 in secondary. If you're making watermelon wheat or orange wheat, then a secondary conditioning tank where the fruit flavor addition is added would make perfect sense.

On other forums I've read about honey weizen beers being left in primary for 3-4 weeks and turned out perfect.

From my limited understanding (only a few brews under my belt) I would think an extra week in the primary (total of 3) would likely do it. I've found that 2 weeks in the bottle has been far too little for my attempts so far, but they have not been wheat beers like yours. If it were me, I'd be thinking 3 in the primary, bottle, and then test @ 2 weeks, @ 3 weeks, etc, and see how the extra time in the bottle effects things.

Curious as to your results, as once my Sierra PA clone is out of the fermenting bucket, I have extract (DME and LME) for a wheat beer ready to go. Just need to get some good hefe yeast and to do my first starter for this one.

How long you need in primary is a product of several factors:
- temperature
- active pitch cell count
- shape of ferementor
- oxygen present in environment.
- and there is probably more

As an newer brewer it is understandable to go by the instructions. However, what you are really looking for out of the primary is terminal gravity (Lowest gravity beer will achieve). To find this out there are several things you can look at. First, look at your airlock, are there still bubbles flowing through it, if yes then obviously it needs to continue in the ferement (so let it ride 3 to 5 more days). Second, this is where your hydrometer or refractometer comes in. Take a sample and check it with your hydrometer or refractometer. This will tell you how much residual sugar is left in solution and whether you should transfer or not. Now residual sugar is specific to the type of beer that you are brewing. However, most of the kits will tell you the final (terminal) gravity of the beer to check for. If not there is a lot of software out there that will give you a decent approximation of what the final gravity should be. There are forumla's out there to do it by hand, but it is so much simpler to let a computer do it for you.

Oh, and a secondary won't be necessary, as all honey will add for the most part is alcohol to the beer. It will contribute a light flavor on lighter, more subtle beer styles. If you want a honey flavor, consider using honey malt in the future it is much easier to achieve that flavor with a honey malt.