Please guys.. I could really use some advice...

Hey guys,
I'm doing my very first grow and I have two 600w hps in ffof soil. I have 21 poison Og kush plants that have been vegging for 30 days. They are 2 1/2 feel already. They are in 1 gallon mediums. I started flowering 3 days ago. My question is do I absolutely have to transplant to a larger medium? I was told by half the people I asked I do and half of them said I don't. But no matter what I need to know soon. Also it's a little warm in there... Around 88 degrees sometimes 90 . I'm working on cooling it down it's just the fan cost 200 dollars. Other that that I have 2 fans in there just regular ones.. Humidity is 30%.I don't know much about this strain because it's new so if anyone can help me with that I'd appreciate it. Flowering time, average yield amount , things like that. I'll post pics very soon. Thanks in advance.

Medium typically refers to the type of material your plants roots will grow in - soil, hydroton, rockwool, etc.

I would tend to think you may need to transplant as my buddy uses an ebb&flow system in which he has a plant sometimes two in each 3 gallon pot - I think 3 gal. He does not veg them that big though and does a some lst...

Dont know much about og kush. I would look it up on google, there are lots of websites out there that have strain libraries that contain specific info - flower time, indica/sativa, where it originated, etc.

Temps are def higher than you want them.