Will 84F stunt growth ?

as above, the temp in my tent at the hottest time of the day gets to 84F is this too hot?

It is a little hot and from my experience you will get a little less if your airflow isn't directed properly in and out of your tent. I know that I may look like a noob to this site but my advice will surprise you if it is taken seriously. This ventilation config will change your life, even though it does not make much sense on paper. Keep a little "dead air" space above your light fixtures. About 6" will do, if not , then as much as possible. Have the air intake (incoming fresh air) situated between your lights at the opposite side of your exhaust ( of course) keeping the bottom of your circular intake opening level with the bottom of your light reflectors. Try to separate the exhaust ports into 3 round openings. 1 directly opposite your incoming fresh air, the other two directly inline with your lights ( if you have 2 rows of lights), or if you have one row of lights simply locate these other two exhaust ports to the left and right of your single row of fixtures. Try to keep your exhaust ports higher than the level line of the bottoms of the reflectors.
By concentrated the air movement up top, the hot air which naturally migrates to the top of the room , is moved with great velocity toward the exhaust. This prevents the hot spot ( which forms and expands around your bulb sort of like a balloon, but not exactly) from expanding unequally downward toward your canopy ( it expands unequally down very much so with regular horizontal reflectors) and redirects it up above your light fixtures. If you can implement this technique, please do so by all means necessary. The only challenge in it is to balance the exhaust flow as equally as possible between all three ports. This can be done by cutting out foam circular rings of varying inner/outer diameter by trial and error.A piece of 3/4" -4'x8' foam board should be more than enough to play with.

no it wont....i try and keep my tent under 86

It wnt hurt them it's fine my room I try to keep at 40 percent humidity and 80 degrees plants love it.....just make Shure they have water I've had my room at 96 degrees and wasn't a problem

That's not to bad for veg as long as you have proper air exchange and a good isolating fan but if it's in flower you might want to try to get it at 80 or under depending on strain. Some sativa's handle warm weather better than indica's. Plants breathe just like everything else so make sure they have intake a exhaust to change out air.

heat that high can give you fluffy buds but smoke will be nice still just not quality or denseness if you keep under 80 but i hear with co2 80-85 is optimal cause they work better in that zone with the boost