Two plants in one container?

[GaGrown]

So, can I plant two plants in one container? I've already done it because I didn't have an extra pot...and it's not turning out so well. The two girls aren't looking nearly as good as their sister, and after about a month in, they don't seem to be growing very fast. HOWEVER, I looked at the bottom of the jar (where the drainage hole is) and there are white roots everywhere. Thats good, no? Help would be much appreciated.

Attachment 282221

Also, there are little gnats (look like fruit flies) hanging around my plant...is this bad?

Those are fungus gnats.. It's not normally the way to go,but.... Your container size is gonna double if not triple,due to the root mass..

Ga.